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Ding L, Niu L, Shi W, Zhou X, Qian Y. Influence of corneal diameter on the accuracy of corneal tomography in patients with forme fruste keratoconus or thin corneas. Clin Exp Optom 2024; 107:788-794. [PMID: 38227767 DOI: 10.1080/08164622.2023.2300297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/22/2023] [Indexed: 01/18/2024] Open
Abstract
CLINICAL RELEVANCE The detection of subclinical ectasia is important in preoperative screening for laser-refractive surgery. Previous studies have confirmed the impact of corneal diameter on the diagnostic accuracy of several ectasia indices in tomographically normal eyes. BACKGROUND This study aimed to investigate the influence of corneal diameter on the diagnostic accuracy of Pentacam tomographic indices in eyes with forme fruste keratoconus (FFKC) and thin corneas. METHODS One hundred and one eyes of 101 patients with FFKC (FFKC group), 104 eyes of 104 patients with a corneal thickness <490 μm (thin cornea group), and 200 eyes of 200 normal subjects (normal group) were analysed in the study. Pentacam ectasia indices were compared between the groups. RESULTS The results of multiple linear regression analysis showed that the standardised coefficients for corneal diameter and overall deviation of normality (BAD-D) were -0.386, -0.552, and -0.552 for the FFKC, thin cornea, and normal groups, respectively (p < 0.001). Comparing for the classifications (normal versus abnormal) of the individual indices demonstrated that for corneal diameters ≤11.9 mm, the rates of abnormal cases were significantly higher in the FFKC group than in the normal group for seven indices and in the thin cornea group than normal group for nine indices. For corneal diameters >11.9 mm, the rates of abnormal cases were higher in the FFKC than normal group for three indices and higher in the thin cornea group than normal group for seven indices. CONCLUSION Belin/Ambrosio Enhanced Ectasia display indices may underestimate the risk of ectasia in patients with large corneas, especially those with FFKC.
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Affiliation(s)
- Lan Ding
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University and NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
| | - Lingling Niu
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University and NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
| | - Wanru Shi
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University and NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
| | - Xingtao Zhou
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University and NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
| | - Yishan Qian
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University and NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
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Zhao SH, Berkowitz C, Ralay Ranaivo H, Laurenti K, Bohnsack BL, Basti S, Rossen JL. Evaluation of parameters for early detection of pediatric keratoconus. BMC Ophthalmol 2024; 24:463. [PMID: 39434060 PMCID: PMC11494742 DOI: 10.1186/s12886-024-03714-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2024] [Accepted: 10/03/2024] [Indexed: 10/23/2024] Open
Abstract
BACKGROUND Keratoconus in children is often more severe and rapidly progressive compared to adults. While Scheimpflug imaging (Pentacam) improves screening, there are no established pediatric guidelines. Due to challenges in diagnosis, we aimed to correlate clinical factors with abnormal imaging results to aid in the development of screening protocols. METHODS A single-center retrospective cohort analysis of patients 3-18 years screened for keratoconus with ophthalmic examination and initial Scheimpflug imaging between 2021 to 2023. Scheimpflug indices including final D, ART max, and calculated CAIRO 8, which is a corneal metric combining pachymetry, ART max, and elevation, were compared to published pediatric ranges for normal and keratoconus corneas. RESULTS Seventy-eight patients (11.8 ± 3.9 years) were screened with the majority referred due to high and/or progressive astigmatism (74 patients, 94%). Forty-nine patients (63%) were male and 48 (62%) self-reported Hispanic ethnicity. Average astigmatism was 4.9 ± 1.8 D and 86% had with-the-rule astigmatism. Fourteen patients (18%) had corneal findings on slit lamp. Average LogMAR CDVA was 0.243 ± 0.274 D. By Pentacam, 55 (70%) patients had ≥ 1 indeterminate or keratoconus value. Patients stratified as keratoconus by all parameters were older (15 vs. 11 years, p = 0.015-0.02), had worse visual acuity (p < 0.0001), and were more likely to have oblique astigmatism (0.0002-< 0.0001) and corneal abnormalities on examination (p < 0.00001) compared to eyes with normal or indeterminate indices. CONCLUSIONS Older age, lower visual acuity, oblique astigmatism, and corneal findings were more commonly found in patients with abnormal screening Pentacam. Most patients clinically suspicious for keratoconus had ≥ 1 indeterminate/abnormal indices. Future studies will follow these patients to identify clinical risk factors for progression.
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Affiliation(s)
- Sharon H Zhao
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
| | | | | | - Kelly Laurenti
- Division of Ophthalmology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Brenda L Bohnsack
- Division of Ophthalmology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Surendra Basti
- Department of Ophthalmology, Northwestern University, Chicago, IL, USA
| | - Jennifer L Rossen
- Division of Ophthalmology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
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Huo Y, Xie R, Chen X, Li S, Zou H, Liu Y, Wang Y. Comparison of a Scheimpflug imaging with other screening indices in diagnosing keratoconus and keratoconus suspect. Sci Rep 2024; 14:23187. [PMID: 39369097 PMCID: PMC11455890 DOI: 10.1038/s41598-024-74497-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Accepted: 09/26/2024] [Indexed: 10/07/2024] Open
Abstract
Keratoconus (KC) is an irreversible blinding eye disease; therefore, early screening of KC suspects (KCS) is crucial for protecting patients' quality of life. Scheimpflug imaging is a commonly used screening device in clinical practice. We aimed to evaluate the diagnostic ability of a Scheimpflug imaging device (Scansys) for KC and KCS and compared it with other Scheimpflug-based devices (Pentacam and Corvis ST). This prospective case-control study included 107 normal eyes, 72 KCS, and 57 KC. Scansys screening index Keratoconus probability (KCP) showed excellent performance in diagnosing KC at a cutoff value of 16.4 (area under the receiver operating characteristic [AUROC] = 1.000), with 100% sensitivity and 98.11% specificity. KCP had a better KCS diagnostic ability at a cutoff value of 8.9 (AUROC = 0.813) than Corvis biomechanical index (CBI, AUROC = 0.764), reaching 67.61% sensitivity and 85.85% specificity. Pentacam screening index Belin/Ambrósio enhanced ectasia display deviation (BAD-D) showed the best performance with 92.96% sensitivity and 89.62% specificity at a cutoff value of 1.525 (AUROC = 0.970) in diagnosing KCS. Scansys provides accurate KCP parameters in diagnosing KC; however, the efficiency of diagnosing KCS should be further optimized.
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Affiliation(s)
- Yan Huo
- School of Medicine, Nankai University, Tianjin, China
| | - Ruisi Xie
- School of Medicine, Nankai University, Tianjin, China
| | - Xuan Chen
- School of Medicine, Nankai University, Tianjin, China
| | | | - Haohan Zou
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Nankai University Affiliated Eye Hospital, Tianjin, China
- Nankai Eye Institute, Nankai University, No. 4, Gansu Road, Heping District, Tianjin, 300020, China
| | - Yutong Liu
- School of Medicine, Nankai University, Tianjin, China
| | - Yan Wang
- School of Medicine, Nankai University, Tianjin, China.
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Nankai University Affiliated Eye Hospital, Tianjin, China.
- Nankai Eye Institute, Nankai University, No. 4, Gansu Road, Heping District, Tianjin, 300020, China.
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Ganesh M, Arora R, Titiyal JS. Combined corneal biomechanical and tomographical indices in subclinical and forme fruste keratoconus. Indian J Ophthalmol 2024; 72:1337-1345. [PMID: 38990626 DOI: 10.4103/ijo.ijo_766_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Accepted: 05/17/2024] [Indexed: 07/12/2024] Open
Abstract
PURPOSE Evaluation of combined corneal tomographic and biomechanical parameters in subclinical/forme fruste keratoconus (ScKC/FFKC). DESIGN Cross-sectional observational case-control study. METHODS INCLUSION CRITERIA Thirty-one eyes with ScKC (fellow eye of KC with any one sign: keratometry >47 diopters, cylinder >1.5 D, central corneal thickness <500 µm, with/without abnormal topography) or FFKC (fellow eye of KC with normal topography and slit lamp examination) >13 years (cases) and 44 eyes of age-matched 22 healthy subjects (controls). EXCLUSION CRITERIA Clinically diagnosed KC, presence of corneal scars, and prior ocular surgery eyes. STUDY PARAMETERS Sixteen Pentacam, 15 Corvis ST, and five Sirius parameters were analyzed using paired sample t -test, and a subsample found to be significantly different was used in receiver operating characteristic curve analysis. The Youden index was calculated, and Pearson's correlation analysis was done. RESULTS Five Pentacam, three Corvis ST, and two Sirius parameters had an area under curve (AUC) >0.75. Tomographic and biomechanical index (TBI) (cutoff 0.59, 95% specificity, 77% sensitivity), Belin Ambrosio enhanced ecstasia display (cutoff 1.8, 81% specificity, 80% sensitivity), and symmetry index of posterior corneal curvature (cutoff 0.16, 97% specificity, 67% sensitivity) best identified early KC. TBI strongly correlated with maximum Pentacam parameters in both cases and controls. Corvis biomechanical index strongly correlated only in cases, and SP-A1-SD weakly correlated in cases. CONCLUSION Upon combined analysis, the average sensitivity and specificity, respectively, of top three parameters (according to AUC) from Pentacam and Corvis ST were 74.1% and 95.4% for posterior elevation and TBI. TRIAL REGISTRATION The trial was registered in Clinical Trial Registry of India on January 28, 2022. The Trial Registration Number is REF/2022/01/050638.
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Affiliation(s)
- Meghna Ganesh
- Guru Nanak Eye Centre, Maharaja Ranjeet Singh Marg, LNJP Colony, New Delhi, Delhi, India
| | - Ritu Arora
- Guru Nanak Eye Centre, Maharaja Ranjeet Singh Marg, LNJP Colony, New Delhi, Delhi, India
| | - Jeewan S Titiyal
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS Campus Temple, Sri Aurobindo Marg, Ansari Nagar East, New Delhi, Delhi, India
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Lartey S, Appiagyei E. Diagnosis of forme fruste keratoconus with scheimpflug photography in Ghanaian patients. BMC Ophthalmol 2024; 24:285. [PMID: 39009964 PMCID: PMC11251121 DOI: 10.1186/s12886-024-03563-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 07/08/2024] [Indexed: 07/17/2024] Open
Abstract
AIM This study aimed to differentiate moderate to high myopic astigmatism from forme fruste keratoconus using Pentacam parameters and develop a predictive model for early keratoconus detection. METHODS We retrospectively analysed 196 eyes from 105 patients and compared Pentacam variables between myopic astigmatism (156 eyes) and forme fruste keratoconus (40 eyes) groups. Receiver operating characteristic curve analysis was used to determine the optimal cut-off values, and a logistic regression model was used to refine the diagnostic accuracy. RESULTS Statistically significant differences were observed in most Pentacam variables between the groups (p < 0.05). Parameters such as the Index of Surface Variance (ISV), Keratoconus Index (KI), Belin/Ambrosio Deviation Display (BAD_D) and Back Elevation of the Thinnest Corneal Locale (B.Ele.Th) demonstrated promising discriminatory abilities, with BAD_D exhibiting the highest Area under the Curve. The logistic regression model achieved high sensitivity (92.5%), specificity (96.8%), accuracy (95.9%), and positive predictive value (88.1%). CONCLUSION The simultaneous evaluation of BAD_D, ISV, B.Ele.Th, and KI aids in identifying forme fruste keratoconus cases. Optimal cut-off points demonstrate acceptable sensitivity and specificity, emphasizing their clinical utility pending further refinement and validation across diverse demographics.
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Affiliation(s)
- Seth Lartey
- Eye Ear Nose and Throat Department, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- Eye Department, Komfo Anokye Teaching Hospital, Kumasi, Ghana
| | - Emmanuel Appiagyei
- Eye Department, Komfo Anokye Teaching Hospital, Kumasi, Ghana.
- Department of Optometry and Visual Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
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Yücekul B, Förster A, Dick HB, Taneri S. Detecting Keratoconus in Adolescents with Anterior Segment Optical Coherence Tomography. J Ophthalmol 2024; 2024:6655217. [PMID: 38881564 PMCID: PMC11178420 DOI: 10.1155/2024/6655217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 04/26/2024] [Accepted: 05/25/2024] [Indexed: 06/18/2024] Open
Abstract
Purpose Assessing the applicability of an algorithm developed for keratoconus detection in adolescents. This algorithm relies on optical coherence tomography (OCT) and incorporates features related to corneal pachymetric and epithelial thickness alterations. Methods We retrospectively reviewed charts of patients under the age of 18 and divided them into four groups according to the Belin-Ambrosio display (Pentacam): normal, manifest, and subclinical keratoconus, as well as very asymmetric eye with normal topography and tomography (VAE-NTT). Corneal and epithelial thickness maps (Cirrus 5000 HD-OCT, Carl Zeiss Meditec, Germany) were evaluated by a human grader. In the first step, if at least one of four parameters (pachymetry minimum (pachy min), pachy minimum-median (min-med), pachy superonasal-inferotemporal (SN-IT), or epithelial (epi SN-IT)) exceeded its cut-off value, the eye was considered as suspect. In the second step, the combined presence of coincident thinning of total cornea and epithelium as well as concentric epithelial thinning lead to the diagnosis of keratoconus. Receiver operating characteristic (ROC) curves were generated to determine area under the curve (AUC), sensitivity, and specificity for the parameters. Results The study involved 19 pediatric patients diagnosed with keratoconus, comprising 29 manifest keratoconic eyes, 3 eyes with subclinical keratoconus, and 5 VAE-NTT eyes. In addition, 22 eyes from 11 normal adolescents were included in the analysis. The AUC values of parameters in step 1 were 0.889 for pachy min, 0.997 for pachy min-med, 0.893 for pachy SN-IT, and 0.998 for epi SN-IT. When both steps were performed, this algorithm captured all manifest and subclinical pediatric keratoconic eyes. When all eyes of the keratoconus patients were combined, step 1 had 97.3% sensitivity and step 2 had 100% specificity. Conclusion Using this OCT-based approach in adolescents yielded a high level of agreement with the current gold standard, tomography. Using them together, potentially also with other examinations may improve the diagnostic accuracy of KC in the pediatric population. Integration of this approach into the software of the device to facilitate automated evaluations is desired.
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Affiliation(s)
- Burcu Yücekul
- Haseki Training and Research Hospital, Department of Ophthalmology, Istanbul, Türkiye
| | - Anika Förster
- Zentrum für Refraktive Chirurgie, Augenzentrum am St. Franziskus Hospital, Münster, Germany
| | | | - Suphi Taneri
- Zentrum für Refraktive Chirurgie, Augenzentrum am St. Franziskus Hospital, Münster, Germany
- Ruhr University Bochum, Eye Clinic, Bochum, Germany
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Buhl L, Feldhaus L, Kassumeh S. [How to: keratoconus assessment using Scheimpflug tomography]. DIE OPHTHALMOLOGIE 2024; 121:239-244. [PMID: 38386091 DOI: 10.1007/s00347-024-02002-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/01/2024] [Indexed: 02/23/2024]
Affiliation(s)
- Lara Buhl
- Augenklinik und Poliklinik, LMU Klinikum, LMU München, Mathildenstr. 8, 80336, München, Deutschland.
| | - Lukas Feldhaus
- Augenklinik und Poliklinik, LMU Klinikum, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Stefan Kassumeh
- Augenklinik und Poliklinik, LMU Klinikum, LMU München, Mathildenstr. 8, 80336, München, Deutschland
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8
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Dong R, Liu Y, Zhang Y, Chen Y. Enhanced morphological assessment based on interocular asymmetry analysis for keratoconus detection. Graefes Arch Clin Exp Ophthalmol 2024; 262:913-926. [PMID: 37792068 DOI: 10.1007/s00417-023-06250-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/09/2023] [Accepted: 09/19/2023] [Indexed: 10/05/2023] Open
Abstract
PURPOSE To clarify the interocular asymmetry of corneal morphological descriptors and evaluate its discriminant ability of keratoconus (KC). METHODS This retrospective study recruited 344 normal participants and 290 KC patients, randomized to training and validation datasets. Interocular correlation and agreement were evaluated on 44 corneal morphological descriptors derived from Schiempflug tomography. Logistic regression models were constructed using binocular data and of which diagnostic performance was evaluated using the area under receiver operating characteristics curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI). RESULTS Interocular agreement of corneal descriptors is better in the normal than in KC except for dimensions of cornea and anterior chamber. The interocular asymmetry increases along with the severity of KC. Interocular asymmetry in maximum anterior keratometry, mean anterior keratometry and higher-order aberrations of anterior surface show high AUC above 0.950. Binocular logistic regression index reaches an AUC of 0.963 with high specificity (95.2%) and brings gain to monocular parameters in distinguishing the normal eyes from KC (NRI = 0.080 (0.042 ~ 0.118), P < 0.001) and IDI = 0.071 (0.049 ~ 0.092), P < 0.001). Interocular asymmetry benefits even more in subclinical keratoconus (SKC) detection reflected by NRI (0.4784 (0.2703-0.6865), P < 0.001) and IDI (0.2680 (0.1495-0.3866), P < 0.001) measures. CONCLUSION Interocular asymmetry is a well-characterized feature of KC and related to the severity. It is feasible to apply the interocular asymmetry in diagnosis of KC and SKC as a replenishment of monocular parameters and in progression tracking.
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Affiliation(s)
- Ruilan Dong
- Department of Ophthalmology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
- Peking University Institute of Laser Medicine, Beijing, China
| | - Yan Liu
- Department of Ophthalmology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
- Peking University Institute of Laser Medicine, Beijing, China
| | - Yu Zhang
- Department of Ophthalmology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
- Peking University Institute of Laser Medicine, Beijing, China
| | - Yueguo Chen
- Department of Ophthalmology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China.
- Peking University Institute of Laser Medicine, Beijing, China.
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Al Somali A, Najmi H, Alsawadi H, Alsawadi H, AlMalki A, Alhamoud M, Alhatlan H, Alwohaibi N. Analysis of Scheimpflug Tomography Parameters for Detecting Subclinical Keratoconus in the Fellow Eyes of Patients with Unilateral Keratoconus in the Eastern Province of Saudi Arabia. Clin Ophthalmol 2024; 18:277-287. [PMID: 38312308 PMCID: PMC10838514 DOI: 10.2147/opth.s443027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/09/2024] [Indexed: 02/06/2024] Open
Abstract
Purpose We compared the characteristics of subtle morphological changes in subclinical keratoconus (KC) and normal corneas using Scheimpflug tomography (Pentacam®) and assessed the efficacy of these parameters for distinguishing KC or subclinical KC from normal eyes. Patients and Methods In this multicenter comparative study at Dhahran Eye Specialist Hospital and Al Kahhal Medical Complex in the Eastern Province of Saudi Arabia, we analyzed the Scheimpflug tomography charts of patients with topographically normal eyes and those with unilateral KC. Patients were divided into the normal (NL: patients considered for refractive surgery and with normal topographic/tomographic features, 129 eyes), KC (30 patients with manifest KC in one eye based on biomicroscopy and topographical findings), and forme fruste KC (FFKC: fellow eyes of patients in the KC group that met the NL group criteria) groups. Corneal morphological parameters were analyzed using the area under the receiver operating characteristic (ROC) curves (AUCs). Results For distinguishing NL and KC groups, all measured corneal morphological parameters, except for flat keratometry, maximum Ambrósio relational thickness index, and minimum sagittal curvature, had AUCs >0.75. The surface variance index yielded the largest AUC (0.999). For distinguishing NL and FFKC groups, all corneal morphological parameters had AUCs <0.8. Total higher-order aberrations (RMS HOA) yielded the highest AUC, followed by Belin/Ambrỏsio Enhanced Ectasia total deviation (BAD-D), back elevation at the thinnest location, average pachymetric progression index (PPIave), and deviation of Ambrỏsio relational thickness (Da) (AUC 0.74-0.78). Conclusion The diagnostic performance of all tested topographic and tomographic parameters measured using Scheimpflug tomography for discriminating subclinical KC was fair at best, with the top parameters being RMS HOA, BAD-D, back elevation at the thinnest location, PPIave, and Da. Distinguishing between subclinical KC and healthy eyes remains challenging. Multimodal imaging techniques may be required for optimal early detection of subtle morphological changes.
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Affiliation(s)
| | - Hatim Najmi
- Department of Ophthalmology, Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia
| | - Hend Alsawadi
- Department of Ophthalmology, Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia
| | - Hassan Alsawadi
- Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Assaf AlMalki
- Department of Ophthalmology, Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia
| | - Mustafa Alhamoud
- Department of Ophthalmology, Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia
| | - Hatlan Alhatlan
- Department of Ophthalmology, King Fahad Hospital, Hofuf, Saudi Arabia
| | - Nada Alwohaibi
- Cornea, External Diseases, and Refractive Surgery Fellow, Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia
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Kuo AN, Cortina MS, Greiner MA, Li JY, Miller DD, Shtein RM, Veldman PB, Yin J, Kim SJ, Shen JF. Advanced Corneal Imaging in Keratoconus: A Report by the American Academy of Ophthalmology. Ophthalmology 2024; 131:107-121. [PMID: 37855776 DOI: 10.1016/j.ophtha.2023.07.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/31/2023] [Accepted: 07/31/2023] [Indexed: 10/20/2023] Open
Abstract
PURPOSE To review the published literature on the diagnostic capabilities of the newest generation of corneal imaging devices for the identification of keratoconus. METHODS Corneal imaging devices studied included tomographic platforms (Scheimpflug photography, OCT) and functional biomechanical devices (imaging an air impulse on the cornea). A literature search in the PubMed database for English language studies was last conducted in February 2023. The search yielded 469 citations, which were reviewed in abstract form. Of these, 147 were relevant to the assessment objectives and underwent full-text review. Forty-five articles met the criteria for inclusion and were assigned a level of evidence rating by the panel methodologist. Twenty-six articles were rated level II, and 19 articles were rated level III. There were no level I evidence studies of corneal imaging for the diagnosis of keratoconus found in the literature. To provide a common cross-study outcome measure, diagnostic sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were extracted. (A perfect diagnostic test that identifies all cases properly has an AUC of 1.0.) RESULTS: For the detection of keratoconus, sensitivities for all devices and parameters (e.g., anterior or posterior corneal curvature, corneal thickness) ranged from 65% to 100%. The majority of studies and parameters had sensitivities greater than 90%. The AUCs ranged from 0.82 to 1.00, with the majority greater than 0.90. Combined indices that integrated multiple parameters had an AUC in the mid-0.90 range. Keratoconus suspect detection performance was lower with AUCs ranging from 0.66 to 0.99, but most devices and parameters had sensitivities less than 90%. CONCLUSIONS Modern corneal imaging devices provide improved characterization of the cornea and are accurate in detecting keratoconus with high AUCs ranging from 0.82 to 1.00. The detection of keratoconus suspects is less accurate with AUCs ranging from 0.66 to 0.99. Parameters based on single anatomic locations had a wide range of AUCs. Studies with combined indices using more data and parameters consistently reported high AUCs. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Anthony N Kuo
- Duke Eye Center, Duke University Medical Center, Durham, North Carolina
| | - Maria S Cortina
- Department of Ophthalmology and Visual Science, University of Illinois College of Medicine, Chicago, Illinois
| | - Mark A Greiner
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine and Institute for Vision Research, University of Iowa, Iowa City, Iowa
| | - Jennifer Y Li
- University of California, Davis Eye Center, University of California, Davis, California
| | - Darby D Miller
- Department of Ophthalmology, Mayo Clinic, Jacksonville, Florida
| | - Roni M Shtein
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Peter B Veldman
- Department of Ophthalmology and Visual Sciences, The University of Chicago, Chicago, Illinois
| | - Jia Yin
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Stephen J Kim
- Department of Ophthalmology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Joanne F Shen
- Department of Ophthalmology, Mayo Clinic, Scottsdale, Arizona.
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Yavangi M, Rabiee S, Sanavi Farimani M, Khansary S, Farhadian M, Ranjbar A, Mahmoudi M, Karimi M, Barati S, Barati Mosleh A, Mohammadpour N. The effects of green tea tablets and metformin on ovulation and menstrual cycle regularity in women with polycystic ovary syndrome. J Med Life 2024; 17:109-115. [PMID: 38737668 PMCID: PMC11080502 DOI: 10.25122/jml-2022-0066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 12/28/2023] [Indexed: 05/14/2024] Open
Abstract
Polycystic ovary syndrome is the most common cause of oligo-ovulation and anovulation among women of reproductive age, contributing to infertility. This study aimed to compare the effects of green tea tablets and metformin on ovulation, menstrual cycle regularity, and antioxidant biomarkers in women with polycystic ovary syndrome (PCOS). In this clinical trial study, 94 women with PCOS were randomly assigned to three groups: green tea (n = 33), metformin (n = 29), and control (n = 32). Menstrual status and oxidative stress parameters, including total antioxidant capacity, thiol, and lipid peroxidation, were compared before and 3 months after the intervention among all three groups. Data analysis was conducted using SPSS software version 22 and employing the analysis of variance and paired t-tests. Following the intervention, the mean menstrual cycle duration in the green tea, metformin, and control groups was 32.22 ± 12.78, 48.72 ± 37.06, and 48.53 ± 31.04 days, respectively (P = 0.040). There was no statistically significant difference between the three groups in terms of biochemical, hormonal, and antioxidant indices before and after the intervention (P > 0.05). The intake of green tea tablets was associated with better outcomes in regulating the menstrual cycle in women with PCOS.
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Affiliation(s)
- Mahnaz Yavangi
- Department of Gynecology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Soghra Rabiee
- Department of Gynecology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Marzieh Sanavi Farimani
- Department of Gynecology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Shahede Khansary
- Department of Gynecology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Maryam Farhadian
- Department of Biostatistics, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Akram Ranjbar
- Department of Biostatistics, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Minoo Mahmoudi
- Department of Biostatistics, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Masoud Karimi
- Department of Biostatistics, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Somayeh Barati
- Department of Biostatistics, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Amir Barati Mosleh
- Department of Biostatistics, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Noushin Mohammadpour
- Department of Biostatistics, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran
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Owusu S, Zaabaar E, Kwarteng MA, Ankamah S, Abowine JBV, Kyei S. Scheimpflug-Derived Keratometric, Pachymetric and Pachymetric Progression Indices in the Diagnosis of Keratoconus: A Systematic Review and Meta-Analysis. Clin Ophthalmol 2023; 17:3941-3964. [PMID: 38143558 PMCID: PMC10749111 DOI: 10.2147/opth.s436492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/07/2023] [Indexed: 12/26/2023] Open
Abstract
Scheimpflug Pentacam Tomography is becoming crucial in the diagnosis and monitoring of keratoconus, as well as in pre- and post-corneal refractive care, but there are still some inconsistencies surrounding its evidence base diagnostic outcome. Therefore, this study aimed at employing meta-analysis to systematically evaluate the keratometric, pachymetric, and pachymetric progression indices used in the diagnosis of Keratoconus. The review protocol was registered with PROSPERO (Identifier: CRD4202310058) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, MEDLINE, Web of Science, and EMBASE were used for data search, followed by a quality appraisal of the included studies using the revised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2). Meta-analysis was conducted using the meta (6.5.0) and metafor (4.2.0) packages in R version 4.3.0, as well as Stata. A total of 32 studies were included in the analysis. All keratometry (K) readings (flattest meridian, K1; steepest meridian, K2, maximum, Kmax) were significantly steeper in keratoconic compared to normal eyes: [MD (95% CI)], K1 [2.67 (1.81; 3.52)], K1-back [-0.71 (-1.03; -0.39)], K1-front [4.06 (2.48; 5.63)], K2 [4.32 (2.89; 5.75)], K2-back [-1.25 (-1.68; -0.82)], K2-front [4.82 (1.88; 7.76)], Kmax [7.57 (4.80; 10.34)], and Kmean [2.80 (1.13; 4.47)]. Additionally, corneal thickness at the center, CCT [-61.19 (-73.79; -48.60)] and apex, pachy-apex [-41.86 (-72.64; -11.08)] were significantly thinner in keratoconic eyes compared to normal eyes. The pooled estimates for pachymetric progression index (PPI): PPImin [0.66 (0.43; 0.90)], PPImax [1.26 (0.87; 1.64)], PPIavg [0.90 (0.68; 1.12)], and Ambrosio relational thickness (ART): ARTmax [-242.77 (-288.86; -196.69)], and ARTavg [-251.08 (-308.76; -195.39)] revealed significantly more rapid pachymetric progression in keratoconic eyes than in normal eyes. The Pentacam Scheimpflug-derived keratometric, pachymetric, and pachymetric progression indices are good predictors in discriminating KC from normal eyes.
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Affiliation(s)
- Sandra Owusu
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
| | - Ebenezer Zaabaar
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Michael Agyemang Kwarteng
- Department of Optometry, Bindura University of Science Education, Bindura, Zimbabwe
- Discipline of Optometry, University of Kwazulu-Natal, Durban, South Africa
| | - Samuel Ankamah
- University of Ghana Library System, University of Ghana, Accra, Ghana
| | | | - Samuel Kyei
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
- Biomedical and Clinical Research Center, University of Cape Coast, Cape Coast, Ghana
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Li J, Zhang BN, Jhanji V, Wang X, Li D, Du X. Parental Corneal Tomographic and Biomechanical Characteristics of Patients With Keratoconus. Am J Ophthalmol 2023; 256:146-155. [PMID: 37567431 DOI: 10.1016/j.ajo.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/19/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023]
Abstract
PURPOSE To investigate the hereditability of corneal tomographic and biomechanical parameters in keratoconus (KC). DESIGN Prospective cohort study. METHODS This study was conducted at Qingdao Eye Hospital of Shandong First Medical University in Qingdao, China. Forty-four patients with KC and their biological parents (n = 88) were recruited as the study group. The control group consisted of 84 healthy adults with matched age and gender. Both eyes of each participant underwent clinical examinations, and 1 eye was selected for statistical analysis. Exclusion criteria were as follows: individuals with glaucoma, ocular surgery, systemic diseases known to affect the eyes, or poor cooperation during examination. Subjects were asked to discontinue soft contact lens (CL) wear for 2 weeks and rigid gas permeable CL wear for 4 weeks before ocular examination. All participants underwent a comprehensive assessment including Pentacam Scheimpflug tomography, Corvis ST, visual acuity, refraction examination, axial length, and slitlamp examination for both eyes. Individuals presenting with KC manifestations in at least 1 eye were classified as having KC. A total of 9 Pentacam indices including keratometry in the flat/steep meridian (K1/K2), maximal keratometry (Kmax), thinnest point pachymetry (TP), and maximum/average Ambrósio relational thickness (ARTmax/ARTave), anterior and posterior surfaces elevation of the cornea (Ef/Eb) and total deviation value (Final D), and 21 biomechanical indices were collected. Associations of these factors with KC were evaluated using multiple comparison and binary logistics regression analyses. RESULTS Two parents (2.27%) from 2 different families were diagnosed with KC. Parents of patients with KC had thinner corneas with altered corneal biomechanical parameters compared with healthy controls (P < .05). The combined tomographic and biomechanical index demonstrated the highest discriminatory power (area under the receiver operating characteristic curve 0.785) and strong specificity (84.5%). Parental corneal tomographic and biomechanical index, Corvis biomechanical index, and TP were identified as the major influential factors for KC in their offspring by logistic regression analysis, with a 73.3% accuracy in identifying offspring with KC. CONCLUSIONS Parental corneal tomographic and biomechanical properties of patients with KC suggest a possible predisposition to KC. A combination of tomography and corneal biomechanics can be helpful in predicting the incidence rate of KC in the offspring of patients with subclinical KC.
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Affiliation(s)
- Jie Li
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China
| | - Bi Ning Zhang
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China
| | - Vishal Jhanji
- Department of Ophthalmology (V.J.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Xiaochuan Wang
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China
| | - Dewei Li
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China
| | - Xianli Du
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China.
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Abdul Fattah M, Mireskandari K, Fung SSM, Woo JH, Ali A. Children with high astigmatism: tomographic and refractive characteristics and the ability of current indices to rule out keratoconus. J AAPOS 2023; 27:328.e1-328.e7. [PMID: 39195354 DOI: 10.1016/j.jaapos.2023.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 09/19/2023] [Indexed: 08/29/2024]
Abstract
PURPOSE To assess corneal tomographic, topographic, and refractive changes in children with high astigmatism and their ability to exclude keratoconus. METHODS In this longitudinal observational study, the medical records of children with high regular cylindrical refraction of ≥3.50 D referred to the Hospital for Sick Children, Toronto, to exclude keratoconus between January 2009 and June 2020 were reviewed retrospectively. Corneal tomography records (Scheimpflug imaging) were reviewed for subjects with total astigmatism of ≥ +3.50 D by retinoscopy. Children with abnormal anterior segment examination and/or other risk factors for corneal disease or ectasia and those with unreliable corneal tomography were excluded. Baseline demographic, longitudinal tomographic, topographic, and refractive data were analyzed. RESULTS A total of 67 eyes of 37 children (mean age, 9.1 ± 3.5 years) were included. Mean cylindrical refraction at presentation was 5.10 ± 1.30 D. Mean follow-up was 2.3 ± 1.8 years. Twenty-nine eyes had Kmax ≥47.20 D at baseline, with no change at last follow-up. Ksteep, Kmax, and thinnest pachymetry were 46.44 ± 2.33 D, 47.06 ± 2.57 D, and 525.86 ± 35.45 μm, respectively, at baseline compared with 46.40 ± 2.28 D, 46.98 ± 2.40 D, and 527.61 ± 37.67 μm at last follow-up (P > 0.05). All eyes were predicted as not having keratoconus using inferior-superior dioptric asymmetry ratio (I-S ratio), and the keratometry, inferior-superior, and astigmatism index (KISA%), which also incorporates skew percentage. The other tomographic indices predicted keratoconus or subclinical keratoconus in at least 22.4% of eyes. All parameters did not significantly change during follow-up. CONCLUSIONS In the absence of other risk factors for keratoconus, children with high regular astigmatism demonstrated clinical and tomographic stability over time. Based on our results, we recommend that I-S ratio and KISA% be primarily used when monitoring normal children with high astigmatism to rule out keratoconus-related changes.
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Affiliation(s)
- Maamoun Abdul Fattah
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Kamiar Mireskandari
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Simon S M Fung
- Department of Ophthalmology, University of California Los Angeles, Los Angeles, California
| | - Jyh Haur Woo
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada; Singapore National Eye Centre, Singapore
| | - Asim Ali
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.
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15
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Saad A, Debellemanière G, Zeboulon P, Rizk M, Rouger H, Mazharian A, Grise-Dulac A, Panthier C, Gatinel D. Discrimination between keratoconus, forme fruste keratoconus, and normal eyes using a novel OCT-based tomographer. J Cataract Refract Surg 2023; 49:1092-1097. [PMID: 37532249 DOI: 10.1097/j.jcrs.0000000000001275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/25/2023] [Indexed: 08/04/2023]
Abstract
PURPOSE To combine objective machine-derived corneal parameters obtained with new swept-source optical coherence tomography (SS-OCT) tomographer (Anterion) to differentiate between normal (N), keratoconus (KC) and forme fruste KC (FFKC). SETTING Laser Center, Hôpital Fondation Adolphe de Rothschild, Paris, France. DESIGN Retrospective study. METHODS 281 eyes of 281 patients were included and divided into 3 groups: N (n = 156), FFKC (n = 43), and KC (n = 82). Eyes were included in each group based on objective evaluation using Nidek Corneal Navigator, and subjective evaluation by authors. The SS-OCT system provided anterior and posterior corneal surface and pachymetry derived variables. The training set was composed of 143 eyes (95 N, 43 FFKC). Discriminant analysis was used to determine the group of an observation based on a set of variables. The obtained formula was tested in the validation set composed of 61 N and 82 KC. RESULTS Among curvature parameters, the FFKC had significantly higher irregularity index at 3 mm and 5 mm, higher inferior-superior index, higher SteepK-OppositeK index and inferiorly decentered posterior steepest keratometry. Among thickness parameters: central pachymetry, thinnest pachymetry, percentage of thickness increase from center to periphery, and inferior decentration of the thinnest point were statistically different between groups. Combination of multiple variables into a discriminant function (F1) included 5 parameters and reached an area under the receiver operating characteristic curve (AUROC) of 0.95 (sensitivity = 75%, specificity = 98.5%) for detection of FFKC. F1 differentiates N from KC with AUROC = 0.99 (sensitivity = 99%, specificity = 99%). CONCLUSIONS Combining anterior and posterior curvatures variables along with pachymetric data obtained from SS-OCT allowed automated detection of early KC and KC with very good accuracy (87% and 99.5% respectively).
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Affiliation(s)
- Alain Saad
- From the Department of Ophthalmology, Rothschild Foundation Hospital, Paris, France (Saad, Debellemanière, Zeboulon, Rizk, Rouger, Mazharian, Grise-Dulac, Panthier, Gatinel); CEROV-Center of Expertise and Research in Visual Optics, Paris, France (Saad, Debellemanière, Zeboulon, Rizk, Rouger, Mazharian, Grise-Dulac, Panthier, Gatinel)
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16
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Dong R, Liu Y, Zhang Y, Chen Y. The application of corneal biomechanical interocular asymmetry for the diagnosis of keratoconus and subclinical keratoconus. Front Bioeng Biotechnol 2023; 11:1266940. [PMID: 37869711 PMCID: PMC10587551 DOI: 10.3389/fbioe.2023.1266940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 09/20/2023] [Indexed: 10/24/2023] Open
Abstract
Purpose: To evaluate the interocular consistency of biomechanical properties in normal, keratoconus (KC) and subclinical keratoconus (SKC) populations and explore the application of interocular asymmetry values in KC and SKC diagnoses. Methods: This was a retrospective chart-review study of 331 ametropic subjects (control group) and 207 KC patients (KC group, including 94 SKC patients). Interocular consistency was evaluated using the intraclass correlation coefficient (ICC). Interocular asymmetry was compared between the control and KC groups and its correlation with disease severity was analyzed. Three logistic models were constructed using biomechanical monocular parameters and interocular asymmetry values. The diagnostic ability of interocular asymmetry values and the newly established models were evaluated using receiver operating characteristic curves and calibration curves. Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were also estimated. Results: The interocular consistency significantly decreased and the interocular asymmetry values increased in KC patients compared with those in control individuals. In addition, the interocular asymmetry values increased with respect to the severity of KC. The binocular assisted biomechanical index (BaBI) had an area under the curve (AUC) of 0.998 (97.8% sensitivity, 99.2% specificity; cutoff 0.401), which was statistically higher than that of the Corvis biomechanical index [CBI; AUC = 0.935, p < 0.001 (DeLong's test), 85.6% sensitivity]. The optimized cutoff of 0.163 provided an AUC of 0.996 for SKC with 97.8% sensitivity, which was higher than that of CBI [AUC = 0.925, p < 0.001 (DeLong's test), 82.8% sensitivity]. Conclusion: Biomechanical interocular asymmetry values can reduce the false-negative rate and improve the performance in KC and SKC diagnoses.
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Affiliation(s)
- Ruilan Dong
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
- Peking University Institute of Laser Medicine, Beijing, China
| | - Yan Liu
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
- Peking University Institute of Laser Medicine, Beijing, China
| | - Yu Zhang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
- Peking University Institute of Laser Medicine, Beijing, China
| | - Yueguo Chen
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
- Peking University Institute of Laser Medicine, Beijing, China
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Tran TM, Mittal A, Naik V, Chhadva P, Wade M, Garg S. Prevalence of subclinical keratoconus and impact on adults undergoing routine, uncomplicated age-related cataract extraction. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1269439. [PMID: 38983071 PMCID: PMC11182208 DOI: 10.3389/fopht.2023.1269439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 08/30/2023] [Indexed: 07/11/2024]
Abstract
Aim To determine the prevalence of subclinical keratoconus (SKCN) among individuals undergoing routine, uncomplicated age-related cataract surgery and its impact on visual and refractive outcomes. Patient and Methods At a major academic ophthalmology department in the United States, we reviewed records of patients aged 50 years and older who underwent surgery from January 2011 to June 2022. We excluded patients who had poor-quality or unreliable tomographic data, previous corneal surgery, keratorefractive procedures, and significant vision-limiting ocular pathology. We defined SKCN if an eye had a Belin-Ambrósio enhanced ectasia index (BAD-D) ≥1.7, which was based on the results of a meta-analysis of large studies. In addition to the BAD-D cutoff, the eye had to deviate significantly on at least one of seven additional parameters: 1) posterior elevation at thinnest point, 2) index of vertical asymmetry, 3) index of surface variation, 4) total front higher order aberrations, 5) front vertical coma, 6) front secondary vertical coma, 7) back vertical coma. An individual had SKCN if at least one eye met the tomography-based classification and did not have manifest KCN in either eye. Visual and refractive outcomes data were acquired from patients of one experienced cataract surgeon with cases done from July 2021 to June 2022. Statistical significance was set at p < 0.05. Results Among 5592 eyes from 3828 individuals, the prevalence of SKCN was 24.7% (95% CI, 23.4 - 26.1, 945 individuals), and the prevalence of KCN was 1.9% (95% CI, 1.6 - 2.4, 87 individuals). The prevalence of SKCN did not increase with age and was more prevalent among females and non-white races. Median post-operative month one distance-corrected visual acuity (DCVA) and proportion of eyes with improvement in DCVA were similar between normal and SKCN eyes. The proportion of eyes reaching ±0.5 and ±1.0 diopter within the refractive target were similar between normal and SKCN eyes. Conclusion SKCN is highly prevalent and should be detected but is unlikely to have a significant deleterious effect on outcomes in routine, uncomplicated cataract surgery.
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Affiliation(s)
- Tu M Tran
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, United States
| | - Aman Mittal
- Dean McGee Eye Institute, University of Oklahoma, Oklahoma, OK, United States
| | - Vihar Naik
- School of Medicine, University of California, Irvine, Irvine, CA, United States
| | - Priyanka Chhadva
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Matthew Wade
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Sumit Garg
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
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Niazi S, Jiménez-García M, Findl O, Gatzioufas Z, Doroodgar F, Shahriari MH, Javadi MA. Keratoconus Diagnosis: From Fundamentals to Artificial Intelligence: A Systematic Narrative Review. Diagnostics (Basel) 2023; 13:2715. [PMID: 37627975 PMCID: PMC10453081 DOI: 10.3390/diagnostics13162715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
The remarkable recent advances in managing keratoconus, the most common corneal ectasia, encouraged researchers to conduct further studies on the disease. Despite the abundance of information about keratoconus, debates persist regarding the detection of mild cases. Early detection plays a crucial role in facilitating less invasive treatments. This review encompasses corneal data ranging from the basic sciences to the application of artificial intelligence in keratoconus patients. Diagnostic systems utilize automated decision trees, support vector machines, and various types of neural networks, incorporating input from various corneal imaging equipment. Although the integration of artificial intelligence techniques into corneal imaging devices may take time, their popularity in clinical practice is increasing. Most of the studies reviewed herein demonstrate a high discriminatory power between normal and keratoconus cases, with a relatively lower discriminatory power for subclinical keratoconus.
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Affiliation(s)
- Sana Niazi
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran P.O. Box 1336616351, Iran;
| | - Marta Jiménez-García
- Department of Ophthalmology, Antwerp University Hospital (UZA), 2650 Edegem, Belgium
- Department of Medicine and Health Sciences, University of Antwerp, 2000 Antwerp, Belgium
| | - Oliver Findl
- Department of Ophthalmology, Vienna Institute for Research in Ocular Surgery (VIROS), Hanusch Hospital, 1140 Vienna, Austria
| | - Zisis Gatzioufas
- Department of Ophthalmology, University Hospital Basel, 4031 Basel, Switzerland;
| | - Farideh Doroodgar
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran P.O. Box 1336616351, Iran;
- Negah Aref Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran P.O. Box 1544914599, Iran
| | - Mohammad Hasan Shahriari
- Department of Health Information Technology and Management, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran P.O. Box 1971653313, Iran
| | - Mohammad Ali Javadi
- Ophthalmic Research Center, Labbafinezhad Hospital, Shahid Beheshti University of Medical Sciences, Tehran P.O. Box 19395-4741, Iran
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Miura M, Leon P, Nahum Y, Böhm MS, Mimouni M, Belin MW, Johns L, Ciolino JB. Recurrent Keratoconus: Corneal Transplants for Keratoconus Develop Tomographic Ectatic Changes. Cornea 2023; 42:708-713. [PMID: 36730373 DOI: 10.1097/ico.0000000000003149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/04/2022] [Indexed: 02/04/2023]
Abstract
PURPOSE The purpose of this study was to evaluate postoperative Scheimpflug imaging changes during the first 5 years after penetrating keratoplasty (PK) in patients with keratoconus (KC). METHODS This retrospective, interventional case series includes 31 eyes of 31 patients who underwent their first PK with a history of KC. Postoperative Scheimpflug imaging was performed 3 months after the removal of the last suture (baseline) and then repeated 3 and 5 years after the PK. Demographic data, donor and host trephination diameter, and Scheimpflug imaging (Pentacam HR, Oculus, Germany) parameters indicative of ectasia were analyzed to evaluate postoperative graft changes that occur after PK. RESULTS The maximal keratometry (Kmax) progressed significantly between baseline (53.5 ± 6.1 D) and postoperative year 3 and year 5 [56.5 ± 6.1 diopter (D) and 58.8 ± 7.9 D, P < 0.001]. Significant changes were also observed for the anterior best fit sphere and posterior best fit sphere ( P < 0.001 for 3 and 5 years compared with baseline). Kmax increased by at least 2 Ds for 74.2% of patients and up to 7 Ds or more for 25.8% of the patients. A significant inverse correlation was observed for host trephine size and progression of Kmax (r = -0.52, P = 0.01), which indicated that larger host trephination size was associated with a smaller increase in postoperative Kmax. CONCLUSIONS Tomographic graft changes indicative of ectasia were observed within 3 to 5 years after PK in patients with KC. These changes were observed more frequently and sooner after corneal transplants than previously reported.
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Affiliation(s)
- Maria Miura
- Schepens Eye Research Institution, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
- Department of Ophthalmology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Pia Leon
- Schepens Eye Research Institution, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
| | - Yoav Nahum
- Department of Ophthalmology, Rabin Medical Center, Petach Tikva, Israel
- Sackler faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Myriam S Böhm
- Schepens Eye Research Institution, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
- Department of Ophthalmology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Michael Mimouni
- Sackler faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel; and
| | - Michael W Belin
- Ophthalmology & Vision Science, University of Arizona, Marana, AZ
| | - Lynette Johns
- Schepens Eye Research Institution, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
| | - Joseph B Ciolino
- Schepens Eye Research Institution, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
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Abstract
PURPOSE To enumerate the various diagnostic modalities used for keratoconus and their evolution over the past century. METHODS A comprehensive literature search including articles on diagnosis on keratoconus were searched on PUBMED and summarized in this review. RESULTS Initially diagnosed in later stages of the disease process through clinical signs and retinoscopy, the initial introduction of corneal topography devices like Placido disc, photokeratoscopy, keratometry and computer-assisted videokeratography helped in the earlier detection of keratoconus. The evolution of corneal tomography, initially with slit scanning devices and later with Scheimpflug imaging, has vastly improved the accuracy and detection of clinical and sub-clinical disease. Analyzing the alteration in corneal biomechanics further contributed to the earlier detection of keratoconus even before the tomographic changes became evident. Anterior segment optical coherence tomography has proven to be a helpful adjuvant in diagnosing keratoconus, especially with epithelial thickness mapping. Confocal microscopy has helped us understand the alterations at a cellular level in keratoconic corneas. CONCLUSION Thus, the collective contribution of the various investigative modalities have greatly enhanced earlier and accurate detection of keratoconus, thus reducing the disease morbidity.
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Affiliation(s)
- Akhil Bevara
- Department of Cornea and Anterior segment, Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Pravin K Vaddavalli
- Department of Cornea and Anterior segment, Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
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21
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Niu L, Ding L, Qian Y, Zhou X. Comparison of Two Scheimpflug Systems in the Measurements of Eyes with Corneal Diameter Smaller than 11.1 mm. Ophthalmol Ther 2023; 12:125-138. [PMID: 36244046 PMCID: PMC9834470 DOI: 10.1007/s40123-022-00591-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/04/2022] [Indexed: 01/16/2023] Open
Abstract
INTRODUCTION This article aimed to evaluate the measurements of ectasia parameters by two Scheimpflug-based tomography devices, Pentacam and Sirius, for eyes with different corneal diameters (CDs). METHODS This cross-sectional research included subjects from the Fudan University EENT Hospital Refractive Center Database that were followed once a year for at least 3 years with unremarkable slit-lamp examination and normal topography. Pentacam and Sirius examinations were performed on these subjects and the ectasia indices were compared between different CD groups. RESULTS The right eyes of 153 subjects were included (CD ≤ 11.1 mm, n = 50; 11.2-12 mm, n = 52; > 12.0 mm, n = 51). For the ectasia parameters from Pentacam, CD had the greatest influence on the deviation of normality of back elevation (Db, R2 = 0.371, β = - 1.119, P < 0.001), overall deviation of normality (BAD-D, R2 = 0.305, β = - 0.589, P < 0.001), and minimum pachymetric progression index (PPImin, R2 = 0.282, β = - 0.131, P < 0.001). For parameters derived from Sirius, CD had the greatest influence on Baiocchi-Calossi-Versaci index of the back surface (BCVb, R2 = 0.138, β = - 0.179, P < 0.001), keratoconus vertex of the back surface (KVb, R2 = 0.099, β = - 2.273, P < 0.001), and BCV (R2 = 0.071, β = - 0.078, P = 0.001). CD had little influence on surface asymmetry index of the front (SIf) and back surface (SIb), keratoconus vertex of the front surface (KVf), Baiocchi-Calossi-Versaci index of the front surface (BCVf), and Sirius classifier (P > 0.05). CONCLUSIONS For Pentacam, CD mainly influenced indices related to back elevation (BE) and pachymetry progression, whereas for Sirius, CD mainly influenced indices related to BE and corneal aberration.
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Affiliation(s)
- Lingling Niu
- Department of Ophthalmology, Eye and ENT Hospital, NHC Key Laboratory of Myopia, Fudan University, Shanghai, People’s Republic of China
| | - Lan Ding
- Department of Ophthalmology, Eye and ENT Hospital, NHC Key Laboratory of Myopia, Fudan University, Shanghai, People’s Republic of China
| | - Yishan Qian
- Department of Ophthalmology, Eye and ENT Hospital, NHC Key Laboratory of Myopia, Fudan University, Shanghai, People’s Republic of China
| | - Xingtao Zhou
- Department of Ophthalmology, Eye and ENT Hospital, NHC Key Laboratory of Myopia, Fudan University, Shanghai, People’s Republic of China
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Huo Y, Chen X, Cao H, Li J, Hou J, Wang Y. Biomechanical properties analysis of forme fruste keratoconus and subclinical keratoconus. Graefes Arch Clin Exp Ophthalmol 2022; 261:1311-1320. [PMID: 36441226 DOI: 10.1007/s00417-022-05916-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/22/2022] [Accepted: 11/16/2022] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To analyze the biomechanical properties of the eye in patients with unilateral keratoconus with normal (forme fruste keratoconus [FFKC]) or abnormal topography (subclinical keratoconus [SKC]). METHODS This study included 153 eyes of 153 participants, including 95 eyes of patients with unilateral keratoconus, and 58 eyes of 58 healthy controls. Contralateral eyes with unilateral keratoconus were divided into two groups according to clinical manifestations and global consensus: FFKC (n = 30) and SKC (n = 65). The biomechanical characteristics were analyzed using non-parametric tests; further analysis thereof was performed after adjusting for confounding factors (i.e., intraocular pressure, age, and corneal thickness). Receiver operating characteristic curve (ROC) was used to analyze the ability of the biomechanical parameters to distinguish FFKC from SKC. RESULTS Statistically significant differences between the FFKC and SKC groups were found in 9 of the 18 corneal biomechanical parameters analyzed using non-parametric tests. After adjusting for confounding factors, the multivariate analysis still revealed significant statistical differences in A1-time (P = 0.017), integrated radius (IR) (P = 0.024), and tomographic and biomechanical index (TBI, P < 0.001) between the FFKC and SKC groups. Stiffness parameter at first applanation (SP-A1) (Area under ROC [AUROC] = 0.765) demonstrated the strongest distinguishing ability, except for TBI (AUROC = 0.858) and Corvis Biomechanical Index (AUROC = 0.849), however, there was no statistically significant difference in SP-A1 (P = 0.366) between FFKC and SKC. CONCLUSIONS Biomechanical parameters A1-time and IR have a high diversity between FFKC and SKC, besides TBI, and may reflect more subtle changes in corneal biomechanical properties (BPs) preceding SP-A1. The BPs of SKC are weaker than FFKC, which might be a basic and clue for the classification and diagnosis of the severity of early keratoconus in terms of biomechanics.
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Zhao Y, Yang H, Li Y, Wang Y, Han X, Zhu Y, Zhang Y, Huang G. Quantitative Assessment of Biomechanical Properties of the Human Keratoconus Cornea Using Acoustic Radiation Force Optical Coherence Elastography. Transl Vis Sci Technol 2022; 11:4. [PMID: 35666497 PMCID: PMC9185997 DOI: 10.1167/tvst.11.6.4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Quantification of biomechanical properties of keratoconus (KC) corneas has great significance for early diagnosis and treatment of KC, but the corresponding clinical measurement remains challenging. Here, we developed an acoustic radiation force (ARF) optical coherence elastography technique and explored its potential for evaluating biomechanical properties of KC corneas. Methods An ARF system was used to induce the tissue deformation, which was detected by an optical coherence tomography system, and thus the localized point-by-point Young's modulus measurements were achieved. Then, two healthy rabbit eyes were imaged to test the system, after which the human keratoconus cornea was evaluated by using the same method. Three regions were selected for biomechanics analysis: the conical region, the transitional region, and the peripheral region. Results Young's moduli of transitional region ranged from 53.3 to 58.5 kPa. The corresponding values for the peripheral region were determined to be 58.6 kPa and 63.2 kPa, respectively. Young's moduli of the conical region were gradually increased by 18.3% from the center to the periphery, resulting in the minimum and maximum values of 44.9 kPa and 53.1 kPa, respectively. Furthermore, Young's moduli of the anterior and posterior of the center were determined to be 44.9 kPa and 50.7 kPa, respectively. Conclusions Differences in biomechanical properties between the three regions and slight variations within the conical region were clearly distinguished. Biomechanical weakening of the keratoconus cornea was mainly localized in the conical region, especially in the vertex position. Translational Relevance The system may provide a promising clinical tool for the noninvasive evaluation of local corneal biomechanics and thus may have potential applications in early keratoconus detection with further optimization.
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Affiliation(s)
- Yanzhi Zhao
- Nanchang University, Nanchang, P. R. China.,Department of Ophthalmology, The Third Affiliated Hospital of Nanchang University, Nanchang, P. R. China
| | - Hongwei Yang
- Nanchang University, Nanchang, P. R. China.,Department of Ophthalmology, The Third Affiliated Hospital of Nanchang University, Nanchang, P. R. China
| | - Yingjie Li
- Nanchang University, Nanchang, P. R. China.,Department of Ophthalmology, The Third Affiliated Hospital of Nanchang University, Nanchang, P. R. China
| | - Yongbo Wang
- Nanchang University, Nanchang, P. R. China.,Department of Ophthalmology, The Third Affiliated Hospital of Nanchang University, Nanchang, P. R. China
| | - Xiao Han
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, P. R. China
| | - Yirui Zhu
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, P. R. China
| | - Yubao Zhang
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, P. R. China
| | - Guofu Huang
- Nanchang University, Nanchang, P. R. China.,Department of Ophthalmology, The Third Affiliated Hospital of Nanchang University, Nanchang, P. R. China
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Henriquez MA, Hadid M, Moctezuma C, Izquierdo L, Binder PS. The false positive rates for detecting keratoconus and potential ectatic corneal conditions when evaluating astigmatic eyes with Scheimpflug Technology. Eur J Ophthalmol 2022; 32:2532-2546. [PMID: 35313744 DOI: 10.1177/11206721221081467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To quantify the false positive rates for keratoconus (KC) and potential ectatic corneal conditions in highly astigmatism eyes when using published parameters/indices obtained from the Pentacam and Galilei units. SETTING Oftalmosalud Instituto de Ojos, Lima, Peru. DESIGN Prospective cohort study. METHODS 67 consecutive eyes with corneal astigmatism > 1.5 D, with a minimum follow ups of 36 months after an uneventful LASIK procedure were included. Indices for KC and other potential ectatic corneal conditions (subclinical KC, forme fruste KC, suspect KC) were obtained using the Pentacam and Galilei Scheimpflug cameras. MAIN OUTCOME MEASURES The false positive rates for KC and potential ectatic corneal conditions were measured. Cut off values provided by previous studies and company-based parameters were used to assess the rate of false positivity. RESULTS The range of false positive rates for a KC diagnosis depending on the lowest and highest cutoff values were: index of height decentration (61% - 1%), index of surface variance (76% - 0%), Posterior elevation (55% - 0%), maximum Ambrosio Relational thickness (100% - 13%), Belin Ambrosio enhanced ectasia display total deviation value (100% - 4%), Average pachymetric progression index (69% - 3%), Pachymetry at the thinnest point (58% - 1%), CSI Center Surround Index (100%), Differential sector index (51%). CONCLUSION The false positive rates for KC and ectatic corneal conditions vary dramatically depending on the cut-off values used. Some indexes used for diagnosis of potential ectatic corneal conditions are inaccurate in normal, highly astigmatic eyes.
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Affiliation(s)
- Maria A Henriquez
- Research Department, 568280Oftalmosalud Institute of Eyes, Av. Javier Prado Este 1142, San Isidro, Lima 27, Perú
| | - Marta Hadid
- Research Department, 568280Oftalmosalud Institute of Eyes, Av. Javier Prado Este 1142, San Isidro, Lima 27, Perú
| | - Cristobal Moctezuma
- Research Department, 568280Oftalmosalud Institute of Eyes, Av. Javier Prado Este 1142, San Isidro, Lima 27, Perú
| | - Luis Izquierdo
- Research Department, 568280Oftalmosalud Institute of Eyes, Av. Javier Prado Este 1142, San Isidro, Lima 27, Perú
| | - Perry S Binder
- 481087Gavin Herbert Eye Institute, University of California, Irvine, California, USA
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25
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Lin Q, Shen Z. Effect of white-to-white corneal diameter on biomechanical indices assessed by Pentacam Scheimpflug corneal tomography and corneal visualization Scheimpflug technology. Int Ophthalmol 2022; 42:1537-1543. [PMID: 34988748 DOI: 10.1007/s10792-021-02144-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/19/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE To provide evidence for more accurate evaluation of refractive surgery candidates in clinics, this retrospective study investigated the effect of corneal diameter on the biomechanical indices assessed by Pentacam Scheimpflug cornea tomography (Pentacam) and corneal visualization Scheimpflug technology (Corvis ST). METHODS The relevant data were collected of 132 eyes from 132 participants with moderate myopia who were candidates for refractive surgery. Eligible participants were apportioned to 2 groups based on the white-to-white (WTW) corneal diameter: Group A, ≤ 11.5 mm, and Group B, ≥ 11.6 mm. A single clinician performed Pentacam and Corvis ST imaging on each subject for 3 consecutive measurements, and the means were used for statistical analyses. RESULTS Each group comprised 66 eyes. As measured by Pentacam, the 2 groups were comparable regarding Df and Da. For other measurements, Group A had significantly higher K1, K2, Db, Dp, Dt, Do, PPImin, PPImax, PPIavg, while Group B had significantly higher CCT, BFSf, BFSb, and ARTmax. Corvis ST data included DA ratio, SPA1, CBI, TBI, and ARTh. Only the latter showed a significant difference, with ARTh of group A (437.04 ± 76.60) larger than group B (470.46 ± 103.36, p = 0.04). CONCLUSION In a Chinese population, WTW corneal diameter showed effect on biomechanical indices assessed by Pentacam and Corvis ST. Personalized evaluation of these measurements based on corneal diameter should improve the sensitivity and specificity for screening of keratoconus by these devices.
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Affiliation(s)
- Qinghong Lin
- Department of Refractive Surgery, Hefei Bright Eye Hospital, No. 299 Feixi Road, Hefei, 230000, China
| | - Zhengwei Shen
- Department of Refractive Surgery, Hefei Bright Eye Hospital, No. 299 Feixi Road, Hefei, 230000, China.
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26
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Vieira MIS, Jammal AA, Arieta CEL, Alves M, de Vasconcellos JPC. Corneal Scheimpflug topography values to distinguish between normal eyes, ocular allergy, and keratoconus in children. Sci Rep 2021; 11:24275. [PMID: 34931010 PMCID: PMC8688439 DOI: 10.1038/s41598-021-03818-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 12/09/2021] [Indexed: 11/09/2022] Open
Abstract
To identify and compare keratometric, corneal thickness, and elevation parameters and indices among healthy children, ocular allergy, and keratoconus using the OCULUS Pentacam Scheimpflug topography system. This study included healthy children, children with ocular allergy (OA) without keratoconus, and children with keratoconus (KC). The study design consisted of a prospective evaluation and review of medical records from a Brazilian ophthalmology department. The exclusion criteria were inability to undergo the ocular exam, other ocular diseases, contact lens wear, and topographic corneal ectasia. The effect of each corneal parameter was evaluated using univariate and multivariate logistic regression models adjusted for sex and age, and ROC curves were used to assess the ability each variable to discriminate among groups. A total of 182 subjects were included: healthy children (n = 99), children with OA (n = 32), and children with KC (n = 51). Groups differed in terms of sex, with more males in the OA group (73.2%) and the KC group (67.7%) than in the control group (40.9%). All corneal parameters studied differed significantly between the control and KC groups, and between the OA and KC groups; they also differed significantly between the three groups in terms of astigmatism, q-value, CCT, TP, BAD-D, and ARTmax values. We present the first study to describe and compare corneal tomographic parameters in healthy children, OA, and KC. Keratometry indices, ACD, ARTmax, AETP, and PETP were found to be the most useful for differentiating between healthy and KC children.IBR registry number: CAAE 54921916.9.0000.5404.
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Affiliation(s)
- Matheus Ivan Schmitz Vieira
- Department of Ophthalmology and Otorhinolaryngology, School of Medical Sciences, University of Campinas, Rua Tessália Vieira de Camargo, Cidade Universitária, Campinas, São Paulo, 13083887, Brazil.
| | - Alessandro Adad Jammal
- grid.411087.b0000 0001 0723 2494Department of Ophthalmology and Otorhinolaryngology, School of Medical Sciences, University of Campinas, Rua Tessália Vieira de Camargo, Cidade Universitária, Campinas, São Paulo 13083887 Brazil
| | - Carlos Eduardo Leite Arieta
- grid.411087.b0000 0001 0723 2494Department of Ophthalmology and Otorhinolaryngology, School of Medical Sciences, University of Campinas, Rua Tessália Vieira de Camargo, Cidade Universitária, Campinas, São Paulo 13083887 Brazil
| | - Monica Alves
- grid.411087.b0000 0001 0723 2494Department of Ophthalmology and Otorhinolaryngology, School of Medical Sciences, University of Campinas, Rua Tessália Vieira de Camargo, Cidade Universitária, Campinas, São Paulo 13083887 Brazil
| | - Jose Paulo Cabral de Vasconcellos
- grid.411087.b0000 0001 0723 2494Department of Ophthalmology and Otorhinolaryngology, School of Medical Sciences, University of Campinas, Rua Tessália Vieira de Camargo, Cidade Universitária, Campinas, São Paulo 13083887 Brazil
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Astigmatic Vectorial Analysis in Pediatric Keratoconus After Unilateral Cross-Linking Treatment. Cornea 2021; 41:272-279. [PMID: 34864798 DOI: 10.1097/ico.0000000000002924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 09/19/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE The aims of this study were to evaluate the treatment response of pediatric keratoconus (KC) patients to unilateral corneal collagen cross-linking (CXL) in treated eyes, disease progression in untreated eyes, and define the predictive value of astigmatic parameters by astigmatic vectorial analysis. METHODS Pediatric patients with KC with CXL-treated progressive eye and untreated fellow eye were included. Patients with other ocular conditions and a history of previous ocular surgery were excluded. Astigmatic changes in anterior and posterior corneal surfaces were evaluated with vectorial analysis. The receiver operating characteristic curves were analyzed to detect the best parameter that discriminates treated and untreated groups. RESULTS Thirty-two eyes of 16 patients with at least 2-year follow-up were analyzed. The maximum keratometry (K) in CXL-treated eyes remained stable (from 53.51 ± 2.86-53.41 ± 2.84 diopter (D), P = 0.84) while the steepest K increased in untreated eyes (from 47.82 ± 1.71-49.59 ± 3.32 D, P = 0.03). The oblique components of corneal astigmatism in CXL-treated eyes were higher than those of fellow eyes (all P < 0.05), which significantly decreased in the anterior 3-mm zone after treatment (P = 0.048). The mean differential astigmatism magnitudes were significantly higher in treated eyes (all P < 0.05). The refractive centroid remained unchanged in treated eyes (P = 0.553) and shifted in the oblique direction in untreated eyes (P = 0.04). The oblique differential astigmatism in the anterior 7-mm zone showed the highest area under the curve value in predicting treatment efficacy (0.813, 95% confidence interval: 0.646-0.981, P < 0.001). CONCLUSIONS Astigmatic vectorial analysis is an objective tool for longitudinal assessment of clinical outcomes in KC. Changes in the oblique components of corneal astigmatism might predict progression and treatment efficacy.
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Changes in Corneal Morphology with Age in Asian Population: A Multicenter Study of 30,618 Cases. Adv Ther 2021; 38:5763-5776. [PMID: 34704192 PMCID: PMC8572190 DOI: 10.1007/s12325-021-01922-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/14/2021] [Indexed: 11/23/2022]
Abstract
Introduction To evaluate normal reference ranges for corneal morphological parameters and investigate age-related changes in these parameters in Asian subjects with healthy eyes in order to provide reference data for preoperative evaluation of corneal refractive surgery and the early differential diagnosis of subclinical and asymptomatic keratoconus. Methods This cross-sectional, multicenter, observational study was conducted in five provinces of China, from January 2014 through October 2019. It is a retrospective analysis. Examiner-blinded clinical measurements were performed after stratification of the subjects into the following age groups: < 18, 18–30, 31–40, 41–50. We evaluated 30,618 healthy eyes of Chinese subjects who exhibited a normal corneal morphology, had no history of eye surgery or trauma, stopped wearing soft contact lenses for at least 2 weeks (rigid contact lenses for at least 4 weeks), and underwent topographic studies for both eyes on the same day. Results While the anterior and posterior corneal curvatures (K1 and K2) increased with age, corneal astigmatism of the anterior and posterior surfaces (ΔK) and central, minimum, and overall corneal thicknesses decreased with age. Age-related decrease of the overall corneal thickness was more obvious toward the periphery. The anterior and posterior corneal surface heights exhibited a decrease and an increase, respectively. Both index of height asymmetry (IHA) and index of vertical asymmetry (IVA) exhibited an increase with age. Conclusions The cornea exhibits overall thinning with age and gradually changes from a flat ellipse to an elongated ellipse in Asian individuals with healthy eyes. However, the anterior and posterior surfaces become smoother with age. Owing to the very large number of cases, these small differences are statistically significant. The results obtained are consistent with the hypothesis that a normal cornea seems to withstand quite well the effect of IOP, external pressures, and the natural cross-linking.
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Karamichos D, Escandon P, Vasini B, Nicholas SE, Van L, Dang DH, Cunningham RL, Riaz KM. Anterior pituitary, sex hormones, and keratoconus: Beyond traditional targets. Prog Retin Eye Res 2021; 88:101016. [PMID: 34740824 PMCID: PMC9058044 DOI: 10.1016/j.preteyeres.2021.101016] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/13/2022]
Abstract
"The Diseases of the Horny-coat of The Eye", known today as keratoconus, is a progressive, multifactorial, non-inflammatory ectatic corneal disorder that is characterized by steepening (bulging) and thinning of the cornea, irregular astigmatism, myopia, and scarring that can cause devastating vision loss. The significant socioeconomic impact of the disease is immeasurable, as patients with keratoconus can have difficulties securing certain jobs or even joining the military. Despite the introduction of corneal crosslinking and improvements in scleral contact lens designs, corneal transplants remain the main surgical intervention for treating keratoconus refractory to medical therapy and visual rehabilitation. To-date, the etiology and pathogenesis of keratoconus remains unclear. Research studies have increased exponentially over the years, highlighting the clinical significance and international interest in this disease. Hormonal imbalances have been linked to keratoconus, both clinically and experimentally, with both sexes affected. However, it is unclear how (molecular/cellular signaling) or when (age/disease stage(s)) those hormones affect the keratoconic cornea. Previous studies have categorized the human cornea as an extragonadal tissue, showing modulation of the gonadotropins, specifically luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Studies herein provide new data (both in vitro and in vivo) to further delineate the role of hormones/gonadotropins in the keratoconus pathobiology, and propose the existence of a new axis named the Hypothalamic-Pituitary-Adrenal-Corneal (HPAC) axis.
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Affiliation(s)
- Dimitrios Karamichos
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA.
| | - Paulina Escandon
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Brenda Vasini
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Sarah E Nicholas
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Lyly Van
- University of Oklahoma Health Sciences Center, 940 Stanton L Young, Oklahoma City, OK, USA; Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Deanna H Dang
- College of Medicine, University of Oklahoma Health Sciences Center, 940 Stanton L Young, Oklahoma City, OK, USA
| | - Rebecca L Cunningham
- Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Kamran M Riaz
- Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Three-Year Clinical Outcomes and Posterior Corneal Elevation Change After Small Incision Lenticule Extraction in Suspicious Corneas. J Cataract Refract Surg 2021; 48:771-777. [PMID: 34670943 DOI: 10.1097/j.jcrs.0000000000000849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 10/08/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine the long-term clinical outcomes and change in posterior corneal elevation after small incision lenticule extraction (SMILE) in eyes with suspicious tomographic features. SETTING Hospital clinic. DESIGN Retrospective, case-controlled, observational. METHODS This study included 43 patients with suspicious corneas (group A), defined by corneal morphology and a final D score from a Scheimpflug camera (Pentacam), and 43 patients with normal corneal topography (group B). Refraction, visual acuity, and posterior corneal elevation over a 6-mm central diameter, including posterior central elevation (PCE), posterior elevation at the thinnest point (PTE) and posterior maximal elevation (PME), were measured preoperatively and at 6, 12, and 36 months postoperatively. RESULTS The preoperative spherical equivalent was -5.51±1.33 D in group A and -5.41±1.19 D in group B. Postoperative uncorrected distance visual acuity was 20/20 or better in 39/43 eyes (91%) in group A and 41/43 eyes (95%) in group B (P=0.160); all eyes in both groups remained stable or had gained corrected distance visual acuity. The mean change in PCE, PTE and PME at 3 years was -1.22±2.65 μm, -1.21±2.70 μm and -1.00±5.09 μm, respectively, in group A and -1.76±3.25 μm, -1.60±3.33 μm and -1.56±5.01 μm in Group B, indicating a tendency for backward displacement of the posterior surface while the between-group difference was not statistically significant (P=0.154, P=0.547, P=0.319). CONCLUSIONS Refraction, visual outcomes, and posterior corneal shift seem comparable between corneas with normal and suspicious tomographic features three years after SMILE. More long-term studies are warranted to corroborate the findings of this study.
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Lin AN, Mohammed ISK, Munir WM, Munir SZ, Alexander JL. Inter-rater Reliability and Repeatability of Manual Anterior Segment Optical Coherence Tomography Image Grading in Keratoconus. Eye Contact Lens 2021; 47:494-499. [PMID: 34294643 PMCID: PMC8384674 DOI: 10.1097/icl.0000000000000818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To determine the repeatability of corneal measurements from anterior segment optical coherence tomography (AS-OCT) images using ImageJ software in healthy eyes compared with eyes with keratoconus. METHODS Anterior segment OCT images of 25 eyes from 14 healthy subjects and 25 eyes from 15 subjects with keratoconus between the ages of 20 and 80 years were evaluated. Two trained observers used ImageJ to measure the central corneal cross-sectional area and anterior and posterior corneal arc lengths. MedCalc statistical software was used to generate the intraclass correlation coefficient (ICC) and Bland-Altman plots (BAPs) for observer measurements. RESULTS Observer measurements of the central corneal cross-sectional area and anterior and posterior corneal arc lengths yielded an ICC >0.7. The ICC comparing the 3 parameters ranged from 0.75 to 0.84 for the control and 0.96 to 0.98 for the keratoconus group. No systematic proportional bias was detected by the BAPs. There were minimal differences between the 2 observer's measurements, with a mean of the difference of 0.3 mm2, 0 mm, and 0 mm, for the 3 measurements, respectively. CONCLUSIONS This study suggests that ImageJ software is a repeatable and reliable tool in the analysis of corneal parameters from AS-OCT images among patients with keratoconus and may be applicable to AS-OCT imaging protocol development, an area of active keratoconus research.
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Affiliation(s)
- Anna N Lin
- University of Maryland School of Medicine (A.N.L.), Baltimore, MD; and Department of Ophthalmology (I.S.K.M., W.M.M., S.Z.M., J.L.A.), University of Maryland Eye Associates, University of Maryland, Baltimore, MD
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Consejo A, Jiménez-García M, Issarti I, Rozema JJ. Detection of Subclinical Keratoconus With a Validated Alternative Method to Corneal Densitometry. Transl Vis Sci Technol 2021; 10:32. [PMID: 34436543 PMCID: PMC8399563 DOI: 10.1167/tvst.10.9.32] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Purpose To enhance the current standards of subclinical keratoconus screening based on the statistical modeling of the pixel intensity distribution of Scheimpflug images. Methods Scheimpflug corneal tomographies corresponding to 25 corneal meridians of 60 participants were retrospectively collected and divided into three groups: controls (20 eyes), subclinical keratoconus (20 eyes), and clinical keratoconus (20 eyes). Only right eyes were selected. After corneal segmentation, pixel intensities of the stromal tissue were statistically modeled using a Weibull probability density function from which parameter α (pixel brightness) was derived. Further, data were transformed to polar coordinates, smoothed, and interpolated to build a map of the corneal α parameter. The discriminative power of the method was analyzed using receiver operating characteristic curves. Results The proposed platform-independent method achieved a higher performance in discriminating subclinical keratoconus from control eyes (90.0% sensitivity, 95.0% specificity, 0.97 area under the curve [AUC]) than the standard method (Belin-Ambrósio enhanced ectasia display), which uses only corneal morphometry (85.0% sensitivity, 85.0% specificity, 0.80 AUC). Conclusions Analysis of light backscatter at the cornea successfully discriminates subclinical keratoconus from control eyes, upgrading the results previously reported in the literature. Translational Relevance The proposed methodology has the potential to support clinicians in the detection of keratoconus before showing clinical signs.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain.,Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Marta Jiménez-García
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Ikram Issarti
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Jos J Rozema
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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Differentiating highly asymmetric keratoconus eyes using a combined Scheimpflug/Placido device. J Cataract Refract Surg 2021; 46:1588-1595. [PMID: 32818347 DOI: 10.1097/j.jcrs.0000000000000358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To determine the ability to differentiate between normal eyes and clinically unaffected eyes of patients with highly asymmetric keratoconus (AKC) using a Scheimpflug/Placido device. SETTING Tel Aviv Sourasky Medical Center and Enaim Medical Center, Israel. DESIGN Retrospective case-control. METHODS Imaging from a combined Scheimpflug/Placido device (Sirius, C.S.O.) was obtained from 26 clinically unaffected eyes of patients with frank keratoconus in the fellow eye, and 166 eyes from 166 patients with bilaterally normal corneal examinations that underwent uneventful corneal refractive surgery with at least 1 year of follow-up. Receiver operating characteristic curves were produced to calculate the area under the curve, sensitivity, and specificity of 60 metrics, and finally a logistic regression modeling was used to determine optimal variables to differentiate populations. RESULTS The most predictive individual metric able to differentiate between 26 eyes in the case group to 166 eye in the control group was the posterior wall inferior-superior (I-S) ratio, with an receiver operating characteristics (ROC) of 0.862. A combination model of 4 metrics (posterior wall I-S ratio in the central 3 mm, thinnest pachymetry coordinate on the x horizontal axis, posterior asymmetry and asphericity index, corneal volume) yielded an ROC of 0.936, with a sensitivity/specificity pair of 92.3%/87%. Variables related to elevation were not found significant. CONCLUSIONS Using a combination of metrics from a combined Scheimpflug/Placido device, a practical model for discrimination between clinically normal eyes of patients with highly AKC and normal eyes was constructed. Variables related to pachymetry and posterior cornea asymmetry were the most impactful.
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Wu Y, Guo LL, Tian L, Xu ZQ, Li Q, Hu J, Huang YF, Wang LQ. Comparative analysis of the morphological and biomechanical properties of normal cornea and keratoconus at different stages. Int Ophthalmol 2021; 41:3699-3711. [PMID: 34232432 PMCID: PMC8536578 DOI: 10.1007/s10792-021-01929-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 06/19/2021] [Indexed: 11/07/2022]
Abstract
Purpose To compare the morphological and biomechanical properties of normal cornea and keratoconus at different stages. Methods A total of 408 patients (517 eyes) with keratoconus were included in this study. According to the Topographic Keratoconus (TKC) grading method, keratoconus was divided into stage I (TKC = 1, 130 eyes), stage II (TKC = 1–2, 2, 164 eyes), stage III (TKC = 2–3, 3, 125 eyes) and stage IV (TKC = 3–4, 4, 98 eyes). A total of 158 normal subjects (158 eyes) were recruited as the normal group. The corneal morphological parameters and biomechanical parameters were obtained with Scheimpflug tomography (Pentacam) and corneal visualization Scheimpflug technology (Corvis ST), and the receiver operating characteristic (ROC) curves were drawn. Results Each corneal morphological and most biomechanical parameters of the keratoconic eyes were significantly different from those of the normal eyes in this study (p < 0.001). ROC curve demonstrated that most parameters in this study showed high efficiency in diagnosing keratoconus (the area under the ROC (AUC) was > 0.9), with the Belin-Ambrósio deviation (BAD-D) and Tomographic and Biomechanical Index (TBI) showing higher efficiency. The efficiency of BAD-D and TBI was high in differentiating keratoconus at different stages (AUC > 0.963). The comparison of ROC curves of keratoconus at different stages did not reveal statistically significant differences for TBI. Conclusion BAD-D and TBI can effectively diagnose stage I keratoconus. Moreover, the efficiency of TBI is the same in diagnosing keratoconus at all stages, while the diagnostic efficiency of other parameters increases with the increase in keratoconus stages.
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Affiliation(s)
- Ying Wu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Li-Li Guo
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China. .,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, 100730, China.
| | - Ze-Quan Xu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Qian Li
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Jian Hu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Yi-Fei Huang
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Li-Qiang Wang
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China.
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Donoso R, Rodríguez Á, Esteffan K, Lagos C, Aránguiz D, Hernández N. Analysis of OPD-Scan and Pentacam Parameters for Early Keratoconus Detection. Am J Ophthalmol 2021; 226:235-242. [PMID: 33529586 DOI: 10.1016/j.ajo.2021.01.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/15/2020] [Accepted: 01/20/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND PURPOSE: To evaluate Pentacam and OPD-Scan parameters in the early detection of keratoconus. DESIGN Retrospective case-control study. METHODS Case group included 50 clinically unaffected fellow eyes diagnosed with asymmetric keratoconus showing subtle qualitative changes at the 0.5-D sensitivity OPD-Scan scale, as well as normal anterior and back elevation difference map at Belin/Ambrósio enhanced ectasia display (BAD) at the Pentacam. Control group included 172 normal eyes that underwent Lasik surgery and presented no complications throughout the 2-year follow-up period. OPD-Scan and Pentacam parameters were compared, calculating sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). A multivariate analysis was performed using Pentacam or OPD-Scan variables, and a model using variables of both devices. RESULTS Pentacam variables with AUC ≥0.8 were keratoconus index (0.85), index of height decentration (0.81), and overall deviation at BAD (0.8). OPD-Scan variables with AUC ≥0.8 were keratoconus prediction index (0.83), surface asymmetry index (0.83), and total of higher-order trefoil aberration (0.8). In the multivariate analysis, the AUC was 0.85 in the case of OPD-Scan whereas it was 0.89 in the case of Pentacam. When combining all variables from the 2 devices, the AUC was 0.93, with a sensitivity of 82% and a specificity of 94%. CONCLUSIONS Several parameters of OPD-Scan and Pentacam can be useful to differentiate cases from normal control eyes, demonstrating even better results when combining parameters of both devices. Anterior corneal indexes were the most important parameters to discriminate both groups.
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Affiliation(s)
- Rodrigo Donoso
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile.
| | - Álvaro Rodríguez
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
| | - Karim Esteffan
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
| | - Claudio Lagos
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
| | - Diego Aránguiz
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
| | - Nicolás Hernández
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
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Chen S, Li XY, Jin JJ, Shen RJ, Mao JY, Cheng FF, Chen ZJ, Linardaki E, Voulgaraki S, Aslanides IM, Jin ZB. Genetic Screening Revealed Latent Keratoconus in Asymptomatic Individuals. Front Cell Dev Biol 2021; 9:650344. [PMID: 34136477 PMCID: PMC8202288 DOI: 10.3389/fcell.2021.650344] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose To adopt molecular screening in asymptomatic individuals at high risk of developing keratoconus as a combinative approach to prevent subclinical patients from post-refractive surgery progressive corneal ectasia. Methods In this study, 79 Chinese and nine Greek families with keratoconus were recruited, including 91 patients with clinically diagnosed keratoconus as well as their asymptomatic but assumptive high-risk first-degree relatives based on underlying genetic factor. Mutational screening of VSX1, TGFBI, and ZEB1 genes and full clinical assessment including Pentacam Scheimpflug tomography were carried out in these individuals. Results Five variants in VSX1 and TGFBI genes were identified in three Chinese families and one Greek family, and four of them were novel ones. Surprisingly, ultra-early corneal changes in Belin/Ambrosio Enhanced Ectasia Display of Pentacam corneal topography together with co-segregated variants were revealed in the relatives who had no self-reported symptoms. Conclusions Variants of VSX1 and TGFBI genes identified in both the clinically diagnosed and subclinical patients may cause the keratoconus through an autosomal dominant inheritance pattern, with different variable expressivity. Combining genetic with Belin/AmbrosioEnhanced Ectasia Display can be used to identify patients with latent keratoconus. This study indicates that genetic testing may play an important supplementary role in re-classifying the disease manifestation and evaluating the preoperative examination of refractive surgery.
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Affiliation(s)
- Shihao Chen
- Center for Refractive Surgery, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xing-Yong Li
- Center for Refractive Surgery, The Eye Hospital, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | - Jia-Jia Jin
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | - Ren-Juan Shen
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China.,Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China
| | - Jian-Yang Mao
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | - Fei-Fei Cheng
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | - Zhen-Ji Chen
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | | | | | - Ioannis M Aslanides
- Center for Refractive Surgery, The Eye Hospital, Wenzhou Medical University, Wenzhou, China.,Emmetropia Mediterranean Eye Institute, Heraklion, Greece
| | - Zi-Bing Jin
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China.,Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, China
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Doctor K, Vunnava KP, Shroff R, Kaweri L, Lalgudi VG, Gupta K, Kundu G. Simplifying and understanding various topographic indices for keratoconus using Scheimpflug based topographers. Indian J Ophthalmol 2021; 68:2732-2743. [PMID: 33229649 PMCID: PMC7856941 DOI: 10.4103/ijo.ijo_2111_20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Keratoconus (KC) is a progressive ectatic corneal disorder. There are multiple topographic devices and their varied indices used for diagnosis, detecting progression, and deciding management. It is important to understand the repeatablility, intra- test variabililty, and comparability amongst various topographic devices. The Scheimpflug camera-based devices, such as the Pentacam (Oculus, Wetzlar, Germany), Galilei (Ziemer, Biel, Switzerland), and Sirius (Costruzione Strumenti Oftalmici, Florence, Italy) are known to assist in the detection of early keratoconus and subclinical keratoconus. This article reviews the various Scheimpflug camera-based devices in depth, addressing their different indices, diagnostic accuracy, repeatability, and agreement and identifying the strongest parameter of each device. It will guide the practicing clinician by giving practical tips for decision making in the diagnosis and management of keratoconus.
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Affiliation(s)
| | | | - Rushad Shroff
- Cornea, Refractive Surgery and Cataract Services, Shroff Eye Centre, New Delhi, India
| | - Luci Kaweri
- Cataract and Refractive Surgery Services, Narayana Nethralaya Eye Institute, Bengaluru, Karnataka, India
| | | | - Krati Gupta
- Cornea and Refractive Surgery Services, Narayana Nethralaya Eye Institute, Bengaluru, Karnataka, India
| | - Gairik Kundu
- Cornea and Refractive Surgery Services, Narayana Nethralaya Eye Institute, Bengaluru, Karnataka, India
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Automated Keratoconus Detection by 3D Corneal Images Reconstruction. SENSORS 2021; 21:s21072326. [PMID: 33810578 PMCID: PMC8036293 DOI: 10.3390/s21072326] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/20/2021] [Accepted: 03/24/2021] [Indexed: 11/16/2022]
Abstract
This paper presents a technique for the detection of keratoconus via the construction of a 3D eye images from 2D frontal and lateral eye images. Keratoconus is a disease that affects the cornea. Normal case eyes have a round-shaped cornea, while patients who suffer from keratoconus have a cone-shaped cornea. Early diagnosis can decrease the risk of eyesight loss. Our aim is to create a method of fully automated keratoconus detection using digital-camera frontal and lateral eye images. The presented technique accurately determines case severity. Geometric features are extracted from 2D images to estimate depth information used to build 3D images of the cornea. The proposed methodology is easy to implement and time-efficient. 2D images of the eyes (frontal and lateral) are used as input, and 3D images from which the curvature of the cornea can be detected are produced as output. Our method involves two main steps: feature extraction and depth calculation. Machine learning from the 3D images dataset Dataverse, specifically taken by the Cornea/Anterior Segment OCT SS-1000 (CASIA), was performed. Results show that the method diagnosed the four stages of keratoconus (severe, moderate, mild, and normal) with an accuracy of 97.8%, as compared to manual diagnosis done by medical experts.
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Xu G, Hu Y, Zhu S, Guo Y, Xiong L, Fang X, Liu J, Zhang Q, Huang N, Zhou J, Li F, Lei X, Jiang L, Wang Z. A multicenter study of interocular symmetry of corneal biometrics in Chinese myopic patients. Sci Rep 2021; 11:5536. [PMID: 33692402 PMCID: PMC7946893 DOI: 10.1038/s41598-021-84937-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/20/2021] [Indexed: 12/26/2022] Open
Abstract
It is essential to know the normal range of the interocular symmetry of the cornea (ISC) for keratoconus diagnosis and corneal substitutes design. In the present study we investigated the interocular symmetry of corneal biometrics in 6,644 Chinese myopic patients from multiple ophthalmic centers. Corneal biometrics of both eyes were exported from the Pentacam instrument. Interocular symmetry of the corneal biometrics was analyzed by Spearman's correlation test, intraclass correlation coefficient (ICC) analysis and Bland-Altman plot. Significantly strong interocular correlations were found in anterior and posterior corneal curvatures, corneal diameter, corneal thickness, corneal volume, corneal eccentricity, and corneal asphericity (r = 0.87-0.98, all P < 0.001). Moderate interocular correlations were observed in whole corneal astigmatism (r = 0.78) and posterior corneal astigmatism (r = 0.73). ICC between the right and left eyes was 0.94-0.98 for anterior and posterior corneal curvatures, corneal diameter, corneal thickness and corneal volume, 0.80-0.88 for corneal eccentricity and asphericity, and 0.73-0.79 for corneal astigmatism (all P < 0.001). Bland-Altman plot showed that the 95% limit of agreement between both eyes was narrow and symmetric in most of the corneal biometrics, suggesting strong interocular agreements in these corneal biometrics. In conclusion, significant interocular symmetry of corneal biometrics is observed in Chinese myopia patients. Extra attention should be paid to patients with interocular corneal asymmetry.
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Affiliation(s)
- Guihua Xu
- Department of Ophthalmology, Huizhou Municipal Central Hospital, Huizhou, China.,Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China
| | - Yijun Hu
- Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China. .,Aier School of Ophthalmology, Central South University, Fourth Floor, New Century Mansion, 198 Middle Furong Road, Changsha, 410015, China.
| | - Shanqing Zhu
- Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China
| | - Yunxiang Guo
- Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China
| | - Lu Xiong
- Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China
| | - Xuejun Fang
- Aier School of Ophthalmology, Central South University, Fourth Floor, New Century Mansion, 198 Middle Furong Road, Changsha, 410015, China.,Refractive Surgery Center, Shenyang Aier Eye Hospital, Shenyang, China
| | - Jia Liu
- Refractive Surgery Center, Shenyang Aier Eye Hospital, Shenyang, China
| | - Qingsong Zhang
- Refractive Surgery Center, Wuhan Aier Eye Hospital, Wuhan, China
| | - Na Huang
- Refractive Surgery Center, Wuhan Aier Eye Hospital, Wuhan, China
| | - Jin Zhou
- Refractive Surgery Center, Chengdu Aier Eye Hospital, Chengdu, China
| | - Fangfang Li
- Refractive Surgery Center, Chengdu Aier Eye Hospital, Chengdu, China
| | - Xiaohua Lei
- Refractive Surgery Center, Hankou Aier Eye Hospital, Hainan, China
| | - Li Jiang
- Refractive Surgery Center, Hankou Aier Eye Hospital, Hainan, China
| | - Zheng Wang
- Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China.,Aier School of Ophthalmology, Central South University, Fourth Floor, New Century Mansion, 198 Middle Furong Road, Changsha, 410015, China
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Keratoconus Indices and their Determinants in Healthy Eyes of a Rural Population. J Curr Ophthalmol 2021; 32:343-348. [PMID: 33553835 PMCID: PMC7861110 DOI: 10.1016/j.joco.2019.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/24/2019] [Accepted: 10/06/2019] [Indexed: 11/30/2022] Open
Abstract
Purpose: To determine the distribution of keratoconus indices in a 5-93-year-old healthy eyes of a rural population in Iran. Methods: In this cross-sectional study, multi-stage cluster sampling was applied to select subjects from two villages in the north and southwest of Iran. After obtaining informed consent, all subjects underwent ophthalmologic and optometric examinations. Corneal imaging by the Pentacam was done in subjects above 5 years between 9 a.m. and 2 p.m., at least 3 h after wakeup. All subjects who had abnormal keratoconus indices were excluded. Our main outcome was keratometry-flat (Kf), keratometry-steep (Ks), keratoconus index (KI), and central keratoconus index (CKI). Results: The mean ± standard deviation of Kf, Ks, KI, and CKI was 43.12 ± 1.74, 44.25 ± 1.65, 1.02 ± 0.02, and 1.01 ± 0.01, respectively. According to multiple linear regression analysis, the mean index surface variance (ISV) (b: -1.367, P < 0.001), index vertical asymmetry (IVA) (b: -0.012, P < 0.001), KI (b: -0.011, P < 0.001), CKI (b: -0.001, P < 0.001), index height asymmetry (IHA) (b: -0.491, P: 0.005), and index height decentration (IHD) (b: -0.001, P < 0.001) were lower in men compared to women. Moreover, age had an indirect association with ISV (b: -0.030, P < 0.001) and average pachymetric progression index (RPI_avg) (b: -0.001, P < 0.001), and a direct association with KI, CKI, and IHA. Spherical equivalence had an indirect association with KI (b: -0.001, P < 0.001) and RPI_avg (b: -0.004, P < 0.001) and a direct association with CKI (b: 0.001, P < 0.001). Among all variables, sex had the greatest impact on ISV, IVA, KI, IHA, IHD, and minimum sagittal curvature. Conclusions: The Keratoconus indices of our study were similar to other studies. Although age, living place, and type of refractive error were associated with some indices, sex was the strongest determinant of Keratoconus indices in a population of healthy eyes.
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Henriquez MA, Hadid M, Izquierdo L. A Systematic Review of Subclinical Keratoconus and Forme Fruste Keratoconus. J Refract Surg 2021; 36:270-279. [PMID: 32267959 DOI: 10.3928/1081597x-20200212-03] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 02/10/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE To identify the definitions used for the terms sub-clinical keratoconus and forme fruste keratoconus in published articles. METHODS This was a prospective, systematic literature review of the electronic database in PubMed, the Cochrane Library, and LILACS Database of all studies using the keywords "subclinical keratoconus" and/or "forme fruste keratoconus" until August 18, 2017. Two independent reviewers analyzed the data. The inclusion criteria for articles were having analyzed subclinical keratoconus or forme fruste keratoconus eyes with a sample size greater than 10 eyes; containing the definition of subclinical keratoconus or forme fruste keratoconus; and the quality of published reports was assessed using standards quality index methods. The following aspects of the selected articles were then analyzed: inclusion criteria for definition and technology used. RESULTS A total of 198 and 95 studies, respectively, including the definition of subclinical keratoconus and forme fruste keratoconus were collected in an initial search, of which 165 and 73 studies, respectively, were excluded. Definitions for subclinical keratoconus and forme fruste keratoconus included the criteria of having keratoconus in the fellow eye in 72.72% (24 of 33) and 77.27% (17 of 22) of the articles, respectively. A total of 96.97% (32 of 33) and 90.90% (20 of 22) of the studies used more than one parameter to define subclinical keratoconus and forme fruste keratoconus, respectively. The most common extra parameters included normal slit-lamp examination and cornea on slit-lamp biomicroscopy and inferior-superior asymmetry and/or bowtie pattern with skewed radial axes. CONCLUSIONS This review demonstrates the lack of unified criteria to define subclinical keratoconus and forme fruste keratoconus. According to the literature review, the most common subclinical keratoconus definition used refers to an eye with topographic signs of keratoconus and/or suspicious topographic findings under normal slit-lamp examination and keratoconus in the fellow eye and the most common forme fruste keratoconus definition refers to an eye with normal topography, normal slit-lamp examination, and keratoconus in the fellow eye. [J Refract Surg. 2020;36(4):270-279.].
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Alsaif NK, Al-Sharif EM, Alsaif SK, Mousa A, Al-Muammar AM. Corneal elevation indices and pachymetry values of Saudi myopes using scheimpflug imaging. Saudi Med J 2021; 41:168-176. [PMID: 32020151 PMCID: PMC7841643 DOI: 10.15537/smj.2020.2.24876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES To report the corneal elevation and thickness values for Saudi myopes and to evaluate the differences between these parameters in subgroups of this target population. Methods: Pentacam corneal topographic maps of the right eyes of patients visiting Al-Hokama Eye Clinic, Riyadh, Saudi Arabia, a tertiary eye center between January 2009 and December 2015 were retrospectively analyzed in this cross-sectional study. The patients were grouped into 3 categories based on their spherical readings: mild (-0.25 to -2.75D), moderate (-3.00 to -5.75D), and severe (≥-6.00D). Furthermore, patients with cylindrical readings of ≥-1.00 diopter were categorized as having myopic astigmatism, whereas those with less than -1.00 cylindrical diopter were categorized as having simple myopia. Results: Our sample was comprised of 1,276 patients; 838 (65.7%) had simple myopia and 438 (34.3%) had myopic astigmatism. The values for the whole myopic group were as follows: anterior corneal elevation (AE) at the apex= 2.60±1.48 (standard deviation), thinnest AE= 2.56±1.68, posterior elevation (PE) at the apex= 3.67±3.58, thinnest PE= 4.92±3.81, central pachymetry= 550.09±34.29, apical pachymetry=550.73±34.64, and thinnest pachymetry= 546.30±34.61. All of the measurements, except the apical PE and thinnest PE, were statistically significant across the simple and myopic astigmatism groups (p less than 0.05). Comparing the mild to moderate myopia groups revealed a significant difference in the apical AE (p=0.037). Moreover, the comparison between the mild and severe myopia groups revealed that the apical PE and the thinnest PE, as well as the central, apical, and thinnest pachymetry values were statistically significantly different (p less than 0.05). Conclusion: The corneal elevation indices and thicknesses specific to the Saudi myopes were found to be comparable to the international databases in terms of the elevation and thickness in some of the parameters.
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Affiliation(s)
- Norah K Alsaif
- Department of Ophthalmology, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia. E-mail.
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A Combined Biomechanical and Tomographic Model for Identifying Cases of Subclinical Keratoconus. Cornea 2021; 39:461-467. [PMID: 31738245 DOI: 10.1097/ico.0000000000002205] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To develop a combined biomechanical and tomographic model for identifying eyes with subclinical keratoconus (SKC) that are categorized as normal or borderline in the Pentacam Belin/Ambrósio Enhanced Ectasia Display. METHODS This case-control study comprised 62 eyes with SKC and randomly selected eyes of 186 age-matched healthy controls. SKC was defined as the presence of the following: 1) normal topography, topometric indices, and slit lamp; 2) normal or borderline Belin/Ambrósio Enhanced Ectasia Display D index, back and front elevation difference; and 3) keratoconus in the fellow eye. Stepwise logistic regression analysis was performed to identify the best variable combination for detecting SKC cases from Ocular Response Analyzer and Pentacam parameters. Receiver operating characteristic curve analysis was used to determine the predictive accuracy [area under the curve (AUC)] of the model. Based on the predictors in the final logistic regression model, a linear equation was derived using the discriminant function analysis. RESULTS The final model (AUC: 0.948, sensitivity: 87.1%, and specificity: 91.4%) chose corneal hysteresis (CH) and D index from a total of 63 candidate variables. The final model had a higher AUC compared with D (0.933, P = 0.053) and CH (0.80, P < 0.001) alone. According to the discriminant function analysis, a higher CH was required with increasing D index to classify an eye as normal. CONCLUSIONS The proposed combined model provided varying cutoffs for CH and D as a function of the other. The probability plot as a function of CH and D index may be used for identifying eyes with SKC.
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Marques RE, Guerra PS, Quintas AM, Rodrigues W. Characterization of posterior corneal astigmatism in a population with keratoconus. Semin Ophthalmol 2020; 35:352-357. [PMID: 33356752 DOI: 10.1080/08820538.2020.1863436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Background: The curvature of the anterior corneal surface is traditionally used as a surrogate to estimate corneal astigmatism. In recent years, increasing importance has been attributed to posterior corneal astigmatism as an indicator. Our aim is to characterize the posterior corneal surface in a population with keratoconus and investigate its predictive value to keratoconus progression. Methods: Retrospective study from a tertiary care centre (Hospital de Santa Maria, Lisbon, Portugal). Eighty-five patients (85 eyes) with keratoconus were included. All patients had two tomographical examinations ≥12 months apart (Pentacam HR). Vector analysis was used to calculate anterior (ACA), posterior (PCA), and total corneal astigmatism (TCA). Multivariate logistic regression was used to assess the predictive value of PCA to keratoconus progression, adjusting for ACA, TCA and several tomographical indices. Results: Study participants had a mean age of 32 (SD = 12.5) years. Mean tomographical keratoconus classification was 2.16 (SD = 0.95), with a mean Kmax of 55.8D (SD = 7.8). Mean power of PCA, ACA and TCA was, respectively, -0.88D (SD = 0.84), 3.74D (SD = 2.36), and 3.06D (SD = 2.01) and its centroids were 0.44D x 15º, 1.65D x 112º, and 1.61D x 106º, respectively. The power of PCA was ≥0.50, 1.00 and 2.00D in 75.3%, 32.9%, and 3.5% of patients, respectively, inducing against-the-rule astigmatism in 60.0% of patients. On average, ACA overestimated TCA in 0.35D x 151º (p < .01). ACA and TCA were highly correlated but showed a lack of agreement for clinical purposes. A predictive role for PCA was excluded. Conclusions: In this population with keratoconus, PCA contributed substantially to TCA. However, PCA was not a valuable predictor for disease progression.
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Affiliation(s)
- Raquel Esteves Marques
- Department of Ophthalmology, Hospital Santa Maria, Centro Hospitalar, Universitário Lisboa Norte , Lisboa, Portugal.,Ophthalmology Clinic, Faculdade de Medicina, Universidade de Lisboa , Lisboa, Portugal
| | - Paulo Silva Guerra
- Department of Ophthalmology, Hospital Santa Maria, Centro Hospitalar, Universitário Lisboa Norte , Lisboa, Portugal.,Ophthalmology Clinic, Faculdade de Medicina, Universidade de Lisboa , Lisboa, Portugal
| | - Ana Miguel Quintas
- Department of Ophthalmology, Hospital Santa Maria, Centro Hospitalar, Universitário Lisboa Norte , Lisboa, Portugal.,Ophthalmology Clinic, Faculdade de Medicina, Universidade de Lisboa , Lisboa, Portugal
| | - Walter Rodrigues
- Department of Ophthalmology, Hospital Santa Maria, Centro Hospitalar, Universitário Lisboa Norte , Lisboa, Portugal.,Ophthalmology Clinic, Faculdade de Medicina, Universidade de Lisboa , Lisboa, Portugal
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Thulasidas M, Teotia P. Evaluation of corneal topography and tomography in fellow eyes of unilateral keratoconus patients for early detection of subclinical keratoconus. Indian J Ophthalmol 2020; 68:2415-2420. [PMID: 33120630 PMCID: PMC7774224 DOI: 10.4103/ijo.ijo_2129_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose: To analyse topographic and tomographic changes in fellow eyes of unilateral keratoconus patients by comparing them with normal eyes. Methods: This five-year retrospective observational comparative case study included 15 advanced keratoconus eyes of unilateral keratoconus (KCN group), 15 normal fellow eyes of unilateral keratoconus (Fellow eye group) and 34 eyes of normal refractive surgery candidates (Normal group). Topographic and tomographic data, data from enhanced elevation maps, and keratoconus indices were measured in all study eyes using Pentacam. Receiver operating characteristic (ROC) curves were used to evaluate the area under the curve (AUC), sensitivity and specificity of each parameter and identify cut-off points in discriminating between the fellow and normal eyes. Results: Corneal thickness at the apex (CTA, P = 0.001) and at the thinnest point (CTT, P < 0.001), corneal volume (CV, P = 0.007), Belin/Ambrosio Enhanced Ectasia Display (BAD) - thinnest point (Dt, P = 0.002) and thinnest point displacement (Da, P = 0.002) were significantly lower in the fellow group compared to eyes of normal subjects. On ROC curve analysis, the most efficient distinguishing indices between the fellow group and normal controls were BAD - overall D value (AUC = 0.859), Dt (AUC =0.827), Da (AUC = 0.789) followed by pachymetric progression index maximum (AUC = 0.741). Conclusion: BAD-D value and pachymetric progression index could be useful in detecting the earliest form of subclinical keratoconus. However, every single parameter alone is not enough to detect early changes; a combination of different data is required to distinguish subclinical keratoconus.
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Affiliation(s)
- Mithun Thulasidas
- Cornea, Cataract and Refractive Surgery Services, Centre for Sight Eye Institute, New Delhi, India
| | - Prateek Teotia
- Cornea, Cataract and Refractive Surgery Services, Centre for Sight Eye Institute, New Delhi, India
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Ding L, Wang J, Niu L, Shi W, Qian Y. Pentacam Scheimpflug Tomography Findings in Chinese Patients With Different Corneal Diameters. J Refract Surg 2020; 36:688-695. [PMID: 33034361 DOI: 10.3928/1081597x-20200730-02] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 07/30/2020] [Indexed: 01/01/2023]
Abstract
PURPOSE To investigate the Pentacam (Oculus Optikgeräte) Scheimpflug tomography findings in Chinese patients with different corneal diameters. METHODS This prospective cross-sectional study included candidates for correction of myopia with normal tomography (ABCD keratoconus grading system, stage 0). The participants were grouped according to their horizontal corneal diameters. Pentacam ectasia detection indices were compared between different corneal diameter-based groups. RESULTS A total of 643 eyes were included (corneal diameter ⩽ 11 mm, n = 206; 11 to 12 mm, n = 219; ⩾ 12 mm, n = 218). The corneal powers and the thinnest pachymetry were negatively correlated with corneal diameter (linear regression analysis, P < .001). However, the corneal astigmatism was positively correlated with corneal diameter (R2 = 0.03, P < .001). Both the front (FE) and back (BE) elevations were negatively correlated with corneal diameter (FE: R2 = 0.027, P < .001; BE: R2 = 0.274, P < .001). The three pachymetric progression indices (PPI) (minimum, maximum, and average) were negatively correlated with corneal diameter (PPImin: R2 = 0.164, P < .001; PPImax: R2 = 0.06, P < .001; PPIavg: R2 = 0.158, P < .001). The maximum Ambrósio's relational thickness (ARTmax) also was positively correlated with corneal diameter (R2 = 0.031, P < .001). Five normalized indices were negatively correlated with corneal diameter (deviation of normality of the front elevation [Df]: R2 = 0.122, P < .001; deviation of normality of the back elevation [Db]: R2 = 0.47, P < .001; deviation of normality of pachymetric progression [Dp]: R2 = 0.159, P < .001; deviation of normality of relational thickness [Da]: R2 = .031, P < .001; Belin/Ambrósio Enhanced Ectasia display: R2 = 0.32, P < .001) and Dt was positively correlated with corneal diameter (R2 = 0.015, P = .002). Additionally, it was noted that corneal diameter had the greatest influence on Db, Belin/Ambrósio Enhanced Ectasia display (BAD-D), and BE. CONCLUSIONS Corneal diameter has an influence on the BAD parameters, especially Db, BAD-D, and BE, and therefore should be incorporated as an additional variable in BAD analysis. The analytical dimensions should be individualized for eyes with individual corneal diameter. [J Refract Surg. 2020;36(10):688-695.].
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Dimacali V, Balidis M, Adamopoulou A, Kozei A, Kozeis N. A Case of Early Keratoconus Associated with Eye Rubbing in a Young Child. Ophthalmol Ther 2020; 9:667-676. [PMID: 32542504 PMCID: PMC7406581 DOI: 10.1007/s40123-020-00264-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Indexed: 02/07/2023] Open
Abstract
INTRODUCTION Keratoconus usually presents during puberty and is considered rare in young children. METHODS Case report with clinical findings and computerized corneal tomography. RESULTS We report the case of an 8-year-old girl with early bilateral keratoconus who presented with allergic conjunctivitis and persistent eye rubbing. Although our patient did not exhibit steep keratometry, early cones and inferotemporal thinnest corneal thicknesses were detected in both eyes using Scheimpflug imaging (Oculus GmbH Pentacam, Wetzlar, Germany). Belin/Ambrósio total D values were 1.85 on the right and 2.11 on the left. Improvement in best-corrected visual acuity was noted after treatment of allergic eye disease, and corneal tomographic findings remained stable 4 months after initial consult. CONCLUSION This is a case of early diagnosed keratoconus in a young patient. Diagnosis of this condition in young children is challenging, as these patients are less likely to report visual complaints, and clinical examination is usually unremarkable. Keratoconus screening should be considered in children with atopy and eye rubbing behavior regardless of age, even in those with no other associated pathology and with negative family history.
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Affiliation(s)
- Victoria Dimacali
- Ophthalmica Institute of Ophthalmology and Microsurgery, Thessaloniki, Greece
- Makati Medical Center, Metro Manila, Philippines
| | - Miltos Balidis
- Ophthalmica Institute of Ophthalmology and Microsurgery, Thessaloniki, Greece
| | - Aspasia Adamopoulou
- Ophthalmica Institute of Ophthalmology and Microsurgery, Thessaloniki, Greece
| | - Athina Kozei
- Ophthalmica Institute of Ophthalmology and Microsurgery, Thessaloniki, Greece
- Pediatric Eye Center of Greece, Thessaloniki, Greece
- School of Pharmacology, University of Nicosia, Nicosia, Cyprus
| | - Nikolaos Kozeis
- Ophthalmica Institute of Ophthalmology and Microsurgery, Thessaloniki, Greece.
- Pediatric Eye Center of Greece, Thessaloniki, Greece.
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Chan E, Chong EW, Lingham G, Stevenson LJ, Sanfilippo PG, Hewitt AW, Mackey DA, Yazar S. Prevalence of Keratoconus Based on Scheimpflug Imaging: The Raine Study. Ophthalmology 2020; 128:515-521. [PMID: 32860813 DOI: 10.1016/j.ophtha.2020.08.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 01/17/2023] Open
Abstract
PURPOSE To describe the prevalence and systemic associations of keratoconus in young adults in Perth, Western Australia. DESIGN Cross-sectional study. PARTICIPANTS One thousand two hundred fifty-nine participants 20 years of age. METHODS The Raine Study is a multigenerational, longitudinal cohort study based in Perth, Western Australia. This study represents a cross-sectional analysis of the birth cohort on returning for a 20-year follow-up. Participants underwent a detailed ophthalmic examination, including visual acuity assessment and Scheimpflug imaging using the Pentacam (Oculus, Wetzlar, Germany), and completed a health questionnaire. Keratoconus was defined as a Belin/Ambrόsio enhanced ectasia display score of 2.6 or more in either eye based on Pentacam imaging. MAIN OUTCOME MEASURES Prevalence of keratoconus in this cohort. RESULTS Of the 1259 participants, 50.8% were women and 85.7% were White. Fifteen participants had keratoconus in at least 1 eye, giving a prevalence of 1.2% (95% confidence interval, 0.7%-1.9%), or 1 in 84. A significant difference was found in best-corrected visual acuity (0.01 logarithm of the minimum angle of resolution vs. -0.05 logarithm of the minimum angle of resolution; P = 0.007), cylinder (1.25 diopters [D] vs. 0.25 D cylinder; P < 0.001) and spherical equivalent (-1.42 D vs. -0.50 D sphere; P = 0.02) on objective refraction, mean keratometry of the steep meridian (45.19 D vs. 43.76 D; P < 0.001), and mean corneal thickness at the thinnest point (475 μm vs. 536 μm; P < 0.001) between those with and without keratoconus. Keratoconus was associated with regular cigarette smoking (38.5% vs. 14.6%; P = 0.04), but showed no association with gender, race, body mass index, use of spectacles or contact lenses, history of allergic eye disease, or pregnancy. CONCLUSIONS The prevalence of keratoconus in this Australian population-based study of 20-year-old adults was 1.2% (95% confidence interval, 0.7%-1.9%), or 1 in 84, which is one of the highest reported in the world. This has important implications for screening individuals at a younger age so that treatment can be initiated before disease progression.
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Affiliation(s)
- Elsie Chan
- Cornea Unit, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia.
| | - Elaine W Chong
- Cornea Unit, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia; Department of Ophthalmology, Royal Melbourne Hospital, Melbourne, Australia
| | - Gareth Lingham
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), University of Western Australia, Perth, Australia
| | - Louis J Stevenson
- Cornea Unit, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), University of Western Australia, Perth, Australia
| | - Paul G Sanfilippo
- Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia; Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), University of Western Australia, Perth, Australia
| | - Alex W Hewitt
- Cornea Unit, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia; School of Medicine, Menzies Institute of Medical Research, University of Tasmania, Hobart, Australia
| | - David A Mackey
- Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia; Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), University of Western Australia, Perth, Australia; School of Medicine, Menzies Institute of Medical Research, University of Tasmania, Hobart, Australia
| | - Seyhan Yazar
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), University of Western Australia, Perth, Australia; Garvan Institute of Medical Research, Sydney, Australia
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Castro-Luna G, Pérez-Rueda A. A predictive model for early diagnosis of keratoconus. BMC Ophthalmol 2020; 20:263. [PMID: 32615945 PMCID: PMC7331257 DOI: 10.1186/s12886-020-01531-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/26/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The diagnosis of keratoconus in the early stages of the disease is necessary to initiate an early treatment of keratoconus. Furthermore, to avoid possible refractive surgery that could produce ectasias. This study aims to describe the topographic, pachymetric and aberrometry characteristics in patients with keratoconus, subclinical keratoconus and normal corneas. Additionally to propose a diagnostic model of subclinical keratoconus based in binary logistic regression models. METHODS The design was a cross-sectional study. It included 205 eyes from 205 patients distributed in 82 normal corneas, 40 early-stage keratoconus and 83 established keratoconus. The rotary Scheimpflug camera (Pentacam® type) analyzed the topographic, pachymetric and aberrometry variables. It performed a descriptive and bivariate analysis of the recorded data. A diagnostic and predictive model of early-stage keratoconus was calculated with the statistically significant variables. RESULTS Statistically significant differences were observed when comparing normal corneas with early-stage keratoconus/ in variables of the vertical asymmetry to 90° and the central corneal thickness. The binary logistic regression model included the minimal corneal thickness, the anterior coma to 90° and posterior coma to 90°. The model properly diagnosed 92% of cases with a sensitivity of 97.59%, specificity 98.78%, accuracy 98.18% and precision 98.78%. CONCLUSIONS The differential diagnosis between normal cases and subclinical keratoconus depends on the mínimum corneal thickness, the anterior coma to 90° and the posterior coma to 90°.
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Affiliation(s)
- Gracia Castro-Luna
- Department of Nursing, Physiotherapy and Medicine, The University of Almería, Almería, Spain.
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Koc M, Tekin K, Kiziltoprak H, Inanc M, Kosekahya P, Ozulken K, Durukan I. Topometric and Tomographic Evaluation of Subclinical Keratoconus. Ophthalmic Epidemiol 2020; 27:289-297. [PMID: 32172662 DOI: 10.1080/09286586.2020.1741010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To investigate the corneal topometric and tomographic findings that can be used in the diagnosis of subclinical keratoconus. METHODS A retrospective cohort study. The study group was selected from patients with clinically evident keratoconus in one eye and subclinical keratoconus without evident topographic findings in fellow eye. The age-matched control group was selected from patients who were candidates for laser in situ keratomileusis (LASIK) and did not develop ectasia after LASIK surgery at least 1-year follow-up. All subjects underwent topographic, topometric and tomographic (Belin-Ambrósio Enhanced Ectasia Display III) analyses via a Pentacam HR rotating Scheimpflug camera (Oculus, Germany, version 1.20r.98) before LASIK surgery. RESULTS The study group consisted of 151 patients (69 male and 82 female, mean age of 24.8 ± 7.2 years) and the control group also consisted of 150 patients (70 male and 80 female, mean age of 26.0 ± 6.3 years). There were statistically significant differences in all measured topometric (p˂.05) and tomographic (p˂.001) parameters between the eyes with subclinical keratoconus and those of the control group. In discriminating eyes with subclinical keratoconus from normal eyes, final D showed the highest area under curve value (0.858, sensitivity 85.2%, specificity 66.7%), followed by maximum pachymetric progression index (0.809, sensitivity 81.9%, specificity 69.4%) and average pachymetric progression index (0.796, sensitivity 81.9%, specificity 68.1%) in receiver operating characteristic analysis. CONCLUSION Topometric and tomographic parameters might be useful for early detection of keratoconus, but the sensitivity and specificity of any parameter are not high enough to be used alone.
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Affiliation(s)
- Mustafa Koc
- Ophthalmology Department, Ankara Ulucanlar Eye Training and Research Hospital , Ankara, Turkey
| | - Kemal Tekin
- Ophthalmology Department, Ercis State Hospital , Van, Turkey
| | - Hasan Kiziltoprak
- Ophthalmology Department, Ankara Ulucanlar Eye Training and Research Hospital , Ankara, Turkey
| | - Merve Inanc
- Ophthalmology Department, Ercis State Hospital , Van, Turkey
| | - Pinar Kosekahya
- Ophthalmology Department, Ankara Ulucanlar Eye Training and Research Hospital , Ankara, Turkey
| | - Kemal Ozulken
- Ophthalmology Department, TOBB ETU Hospital , Ankara, Turkey
| | - Irfan Durukan
- Ophthalmology department, Era Eye Hospital , Ankara, Turkey
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