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Naujokaitis T, Khoramnia R, Friedrich M, Son HS, Auffarth GU, Augustin VA. Inter-zonal epithelial thickness differences for early keratoconus detection using optical coherence tomography. Eye (Lond) 2024:10.1038/s41433-024-03199-7. [PMID: 39003429 DOI: 10.1038/s41433-024-03199-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 05/09/2024] [Accepted: 06/20/2024] [Indexed: 07/15/2024] Open
Abstract
PURPOSE To develop and test a parameter for early keratoconus screening by quantifying the localized epithelial thickness differences in keratoconic eyes. METHODS The cross-sectional study included 189 eyes of 116 subjects in total: 86 eyes of 54 keratoconus patients with bilateral ectasia and 40 eyes of 20 healthy subjects in the parameter-development dataset and 42 eyes of 21 keratoconus patients with asymmetric ectasia and 21 eyes of 21 healthy subjects in the parameter-validation dataset. Epithelial thickness maps were obtained using anterior segment optical coherence tomography and the inter-zonal epithelial thickness differences were calculated. The developed parameter was tested in keratoconus patients with asymmetric ectasia. RESULTS Compared to healthy controls, the inferior-temporal and global inter-zonal epithelial thickness differences were higher not only in eyes with tomographically significant keratoconus (median [interquartile range] of 4.42 [3.13] µm vs. 0.78 [0.42] µm, p < 0.001, and 3.05 [1.51] µm vs. 1.07 [0.26] µm, p < 0.001, respectively), but also in tomographically normal keratoconus fellow eyes (1.36 [0.85] µm vs. 0.78 [0.42] µm, p = 0.005, and 1.31 [0.32] µm vs. 1.07 [0.26] µm, p = 0.01, respectively). The inferior-temporal inter-zonal epithelial thickness differences had an area under the receiver operating characteristic curve (95% confidence interval) of 0.991 (0.972-1) for detecting tomographically significant keratoconus and 0.749 (0.598-0.901) for differentiating between tomographically normal keratoconus fellow eyes and healthy controls. CONCLUSIONS The inter-zonal epithelial thickness differences are increased in keratoconus fellow eyes which still have a normal Scheimpflug corneal tomography, and therefore may serve as a useful parameter to detect early ectatic changes.
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Affiliation(s)
- Tadas Naujokaitis
- International Vision Correction Research Centre (IVCRC), Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany
| | - Ramin Khoramnia
- International Vision Correction Research Centre (IVCRC), Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany
| | - Maximilian Friedrich
- International Vision Correction Research Centre (IVCRC), Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany
| | - Hyeck-Soo Son
- International Vision Correction Research Centre (IVCRC), Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany
| | - Gerd U Auffarth
- International Vision Correction Research Centre (IVCRC), Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany
| | - Victor A Augustin
- International Vision Correction Research Centre (IVCRC), Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany.
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Rafizadeh SM, Sonbolestan SA, Zeidabadinejad H, Abtahi MA. Blepharoptosis and corneal epithelial thickness alterations, is there any relation? BMC Ophthalmol 2024; 24:282. [PMID: 38997644 PMCID: PMC11241861 DOI: 10.1186/s12886-024-03556-w] [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: 12/29/2023] [Accepted: 07/03/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND To compare the epithelial thickness map of ptotic eyes of blepharoptosis patients with contralateral non- ptotic eyes. METHODS Unilateral blepharoptosis patients were enrolled consecutively. Patients were underwent full ophthalmologic examination and their demographic data such as age and gender and specific ptosis findings e.g. the cause and duration, MRD-1, and levator palpebralis superioris function were registered. Anterior segment imaging for epithelial thickness measurements was done using the Avanti RTVue-XR platform. The corneal epithelial thickness maps of ptotic and non-ptotic eyes were compared. RESULTS 44 patients with unilateral blepharoptosis were included in the study. 27 (61.4%) of them were female and 17 (38.6%) cases were male. The mean of the patients' ages was 24.40 ± 15.16 years. Ptotic eyes had significantly thinner superior (p = 0.000), superior-temporal (p = 0.000) and superior-nasal (p = 0.005) sectors of the cornea and slightly thicker corneal epithelium (CE) in the inferior-nasal sector. The correlation of difference of superior-inferior CE was evaluated with different parameters including patient's age (p = 0.457), type of blepharoptosis (p = 0.786), duration of blepharoptosis (p = 0.477) and MRD1 (p = 0.248), but no correlation was found. CONCLUSIONS This study revealed that lid position in blepharoptosis may have effects on the corneal epithelial thickness map. Because of the lower position of upper eyelid, a thinning effect on superior corneal sectors may happen.
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Affiliation(s)
- Seyed Mohsen Rafizadeh
- Department of oculo-facial plastic and reconstructive Surgery, Eye Research Center, Farabi Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Ali Sonbolestan
- Department of oculo-facial plastic and reconstructive Surgery, Eye Research Center, Farabi Hospital, Tehran University of Medical Sciences, Tehran, Iran.
| | - Haniyeh Zeidabadinejad
- Farabi Hospital, Eye Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad-Ali Abtahi
- Department of cornea and anterior segment, Farabi Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Mohr N, Kassumeh S, Luft N, Dirisamer M, Priglinger SG, Mayer WJ. Enhancing ectasia screening using advanced AS-OCT: a case series of challenging refractive candidates. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1405443. [PMID: 38984129 PMCID: PMC11182286 DOI: 10.3389/fopht.2024.1405443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 05/16/2024] [Indexed: 07/11/2024]
Abstract
Purpose Ectasia screening in candidates for laser refractive surgery is mandatory during preoperative evaluation. Despite the availability of modern imaging techniques, refractive surgeons often face borderline decisions when patients present with suspicious tomographic findings. This case series presents refractive candidates with suspicious tomographic findings and demonstrates how to interpret them using Scheimpflug imaging and additional anterior segment optical coherence tomography (AS-OCT). Setting Department of Ophthalmology, University Hospital, LMU Munich. Case series This case series examines six potential candidates for refractive surgery with a mean age of 29.2 ± 3.9 years, whose corneal assessments using Scheimpflug imaging raised suspicion for ectasia. Each candidate was additionally examined with AS-OCT and reevaluated. The mean manifest subjective spherical equivalent was -3.67 ± 1.8 diopters. The total corneal thickness measured 537 µm ± 30 µm at its thinnest point. None of the candidates had any reported underlying corneal or ophthalmic diseases, and slit lamp examinations revealed no abnormal morphological findings. Conclusions Both Scheimpflug imaging and AS-OCT are appropriate tools for screening refractive candidates for ectasia. While topographic and elevation analyses yielded comparable results regarding corneal structure, the epithelial mapping provided by AS-OCT played a critical role in decision-making for cases with borderline tomographic findings. Establishing a global consensus on the use of epithelial mapping in ectasia screening is necessary.
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Affiliation(s)
- Niklas Mohr
- Department of Ophthalmology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Stefan Kassumeh
- Department of Ophthalmology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Nikolaus Luft
- Department of Ophthalmology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
- Smile Eyes Clinic, Linz, Austria
| | - Martin Dirisamer
- Department of Ophthalmology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
- Smile Eyes Clinic, Linz, Austria
| | - Siegfried G. Priglinger
- Department of Ophthalmology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Wolfgang J. Mayer
- Department of Ophthalmology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
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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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Al Bdour M, Sabbagh HM, Jammal HM. Multi-modal imaging for the detection of early keratoconus: a narrative review. EYE AND VISION (LONDON, ENGLAND) 2024; 11:18. [PMID: 38730479 PMCID: PMC11088107 DOI: 10.1186/s40662-024-00386-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/21/2024] [Indexed: 05/12/2024]
Abstract
Keratoconus is a common progressive corneal disorder that can be associated with significant ocular morbidity. Various corneal imaging techniques have been used for the diagnosis of established cases. However, in the early stages of the disease, which include subclinical keratoconus and forme fruste keratoconus, detection of such cases can be challenging. The importance of detecting such cases is very important because early intervention can halt disease progression, improve visual outcomes and prevent postrefractive surgery ectasia associated with performing corneal refractive procedures in such patients. This narrative review aimed to examine several established and evolving imaging techniques for the detection of early cases of keratoconus. The utilization of combinations of these techniques may further increase their diagnostic ability.
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Affiliation(s)
- Muawyah Al Bdour
- Department of Ophthalmology, School of Medicine, The University of Jordan, Amman, Jordan
| | - Hashem M Sabbagh
- The National Center for Diabetes Endocrinology and Genetics (NCDEG), Amman, Jordan
| | - Hisham M Jammal
- Department of Ophthalmology, Faculty of Medicine, Jordan University of Science and Technology, PO Box 3030, Irbid, 22110, Jordan.
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Hashemi H, Doroodgar F, Niazi S, Khabazkhoob M, Heidari Z. Comparison of different corneal imaging modalities using artificial intelligence for diagnosis of keratoconus: a systematic review and meta-analysis. Graefes Arch Clin Exp Ophthalmol 2024; 262:1017-1039. [PMID: 37418053 DOI: 10.1007/s00417-023-06154-6] [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: 11/12/2022] [Revised: 04/18/2023] [Accepted: 06/16/2023] [Indexed: 07/08/2023] Open
Abstract
PURPOSE This review was designed to compare different corneal imaging modalities using artificial intelligence (AI) for the diagnosis of keratoconus (KCN), subclinical KCN (SKCN), and forme fruste KCN (FFKCN). METHODS A comprehensive systematic search was conducted in scientific databases, including Web of Science, PubMed, Scopus, and Google Scholar based on the PRISMA statement. Two independent reviewers assessed all potential publications on AI and KCN up to March 2022. The Critical Appraisal Skills Program (CASP) 11-item checklist was used to evaluate the validity of the studies. Eligible articles were categorized into three groups (KCN, SKCN, and FFKCN) and included in the meta-analysis. The pooled estimate of accuracy (PEA) was calculated for all selected articles. RESULTS The initial search yielded 575 relevant publications, of which 36 met the CASP quality criteria and were included in the analysis. Qualitative assessment showed that Scheimpflug and Placido combined with biomechanical and wavefront evaluations improved KCN detection (PEA, 99.2, and 99.0, respectively). The Scheimpflug system (92.25 PEA, 95% CI, 94.76-97.51) and a combination of Scheimpflug and Placido (96.44 PEA, 95% CI, 93.13-98.19) had the highest diagnostic accuracy for the detection of SKCN and FFKCN, respectively. The meta-analysis outcomes showed no significant difference between the CASP score and accuracy of the publications (all P > 0.05). CONCLUSIONS Simultaneous Scheimpflug and Placido corneal imaging methods provide high diagnostic accuracy for early detection of keratoconus. The use of AI models improves the discrimination of keratoconic eyes from normal corneas.
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Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Farideh Doroodgar
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Negah Eye Hospital Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sana Niazi
- Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zahra Heidari
- Department of Ophthalmology, Bu-Ali Sina Hospital, Mazandaran University of Medical Sciences, Sari, Iran.
- Psychiatry and Behavioral Sciences Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
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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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Abtahi MA, Beheshtnejad AH, Latifi G, Akbari-Kamrani M, Ghafarian S, Masoomi A, Sonbolastan SA, Jahanbani-Ardakani H, Atighechian M, Banan L, Nouri H, Abtahi SH. Corneal Epithelial Thickness Mapping: A Major Review. J Ophthalmol 2024; 2024:6674747. [PMID: 38205099 PMCID: PMC10776199 DOI: 10.1155/2024/6674747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/27/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
The corneal epithelium (CE) is the outermost layer of the cornea with constant turnover, relative stability, remarkable plasticity, and compensatory properties to mask alterations in the underlying stroma. The advent of quantitative imaging modalities capable of producing epithelial thickness mapping (ETM) has made it possible to characterize better the different patterns of epithelial remodeling. In this comprehensive synthesis, we reviewed all available data on ETM with different methods, including very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) in normal individuals, corneal or systemic diseases, and corneal surgical scenarios. We excluded OCT studies that manually measured the corneal epithelial thickness (CET) (e.g., by digital calipers) or the CE (e.g., by confocal scanning or handheld pachymeters). A comparison of different CET measuring technologies and devices capable of producing thickness maps is provided. Normative data on CET and the possible effects of gender, aging, diurnal changes, refraction, and intraocular pressure are discussed. We also reviewed ETM data in several corneal disorders, including keratoconus, corneal dystrophies, recurrent epithelial erosion, herpes keratitis, keratoplasty, bullous keratopathy, carcinoma in situ, pterygium, and limbal stem cell deficiency. The available data on the potential role of ETM in indicating refractive surgeries, planning the procedure, and assessing postoperative changes are reviewed. Alterations in ETM in systemic and ocular conditions such as eyelid abnormalities and dry eye disease and the effects of contact lenses, topical medications, and cataract surgery on the ETM profile are discussed.
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Affiliation(s)
| | | | - Golshan Latifi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Sadegh Ghafarian
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Masoomi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | | | - Laleh Banan
- Sunshine Coast University Hospital, Brisbane, Queensland, Australia
| | - Hosein Nouri
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed-Hossein Abtahi
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Ning R, Wang Y, Xu Z, Gustafsson I, Li J, Savini G, Schiano-Lomoriello D, Xiao Y, Chen A, Wang X, Zhou X, Huang J. Assessing progression limits in different grades of keratoconus from a novel perspective: precision of measurements of the corneal epithelium. EYE AND VISION (LONDON, ENGLAND) 2024; 11:1. [PMID: 38163895 PMCID: PMC10759576 DOI: 10.1186/s40662-023-00368-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 12/05/2023] [Indexed: 01/03/2024]
Abstract
BACKGROUND To assess repeatability and reproducibility of corneal epithelium thickness (ET) measured by a spectral-domain optical coherence tomographer (SD-OCT)/Placido topographer (MS-39, CSO, Florence, Italy) in keratoconus (KC) population at different stages, as well as to determine the progression limits for evaluating KC progression. METHODS A total of 149 eyes were enrolled in this study, with 29 eyes in the forme fruste keratoconus (FFKC) group, 34 eyes in the mild KC group, 40 eyes in the moderate KC group, and 46 eyes in the severe KC group. Employing the within-subject standard deviation (Sw), test-retest variability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) to evaluate intraoperator repeatability and interoperator reproducibility. RESULTS The repeatability and reproducibility of MS-39 in patients with KC were acceptable, according to ICC values ranging from 0.732 to 0.954. However, patients with more severe KC and progressive peripheralization of the measurement points had higher TRTs but a thinning trend. The current study tended to set the cut-off values of mild KC, moderate KC, and severe KC to 4.9 µm, 5.2 µm, and 7.4 µm for thinnest epithelium thickness (TET). When differences between follow-ups are higher than those values, progression of the disease is possible. As for center epithelium thickness (CET), cut-off values for mild KC, moderate KC, and severe KC should be 2.8 µm, 4.4 µm, and 5.3 µm. This might be useful in the follow-up and diagnosis of keratoconus. CONCLUSIONS This study demonstrated that the precision of MS-39 was reduced in measuring more severe KC patients and more peripheral corneal points. In determining disease progression, values should be differentiated between disease-related real changes and measurement inaccuracies. Due to the large difference in ET measured by MS-39 between various stages of disease progression, it is necessary to accurately grade KC patients to avoid errors in KC clinical decision-making.
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Affiliation(s)
- Rui Ning
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Yiran Wang
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Zhenyu Xu
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Ingemar Gustafsson
- Department of Clinical Sciences, Ophthalmology, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Jiawei Li
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | | | | | - Yichen Xiao
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Aodong Chen
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Xiaoying Wang
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.
| | - Jinhai Huang
- Eye Institute and Department of Ophthalmology and Vision Science, Institute for Medical and Engineering Innovation, Eye and ENT Hospital, Fudan University, N No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.
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10
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Heidari Z, Mohammadpour M, Hajizadeh F, Fotouhi A, Hashemi H. Corneal layer thickness in keratoconus using optical coherence tomography. Clin Exp Optom 2024; 107:32-39. [PMID: 37121670 DOI: 10.1080/08164622.2023.2201369] [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: 02/28/2021] [Accepted: 04/05/2023] [Indexed: 05/02/2023] Open
Abstract
CLINICAL RELEVANCE Accurate thickness measurement of corneal layers using anterior segment OCT can be used to improve visual outcomes. Understanding its applications is essential for optometric practices to enhance eye care procedures. BACKGROUND To evaluate the thicknesses of different corneal layers for identifying keratoconus (KCN) and subclinical keratoconus (SKCN) using spectral-domain optical coherence tomography (SD-OCT). METHODS This prospective study analyzed 60 eyes with KCN, 48 eyes with SKCN, and 53 normal eyes. The central corneal thickness (CCT) and thicknesses of the epithelium, Bowman, stroma, and Descemet-endothelium layers were measured using SD-OCT. One way analysis of variance and the area under the curve (AUC) were used to evaluate the parameters. The Delong method was used to compare AUCs. RESULTS In KCN, CCT and thicknesses of epithelium, Bowman, stroma, and Descemet-endothelium layers were 495.5 ± 41.7, 52.6 ± 6.4,11.5 ± 1.4, 415.5 ± 38.9, and 12.3 ± 1.7 µm, respectively. These thickness values were respectively 524.5 ± 33.3, 56.8 ± 6.8, 11.5 ± 1.6, 439.8 ± 30.6, and 12.4 ± 1.7 µm in SKCN and 563.8 ± 37.9, 57.7 ± 6.9, 12.2 ± 1.6, 469.5 ± 33.7, and 12.8 ± 2.1µm in normal group. Total cornea and stroma in KCN and SKCN, and epithelium in KCN were significantly thinner compared to the normal group (P < 0.001). The highest AUC values were observed for CCT in KCN (AUC 0.90) and SKCN (AUC 0.782). The diagnostic accuracy was significantly higher for stromal thickness in KCN (sensitivity 81.7%, specificity 73.6%, AUC 0.871) and SKCN (sensitivity 80.0%, specificity 56.6%, AUC 0.751) than other individual corneal layers (Delong, P < 0.001) . CONCLUSION CCT can accurately distinguish keratoconus from normal eyes. However, central corneal stromal thinning was the most sensitive diagnostic index for early detection of SKCN. Developing standardized stromal maps may be helpful for detecting SKCN.
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Affiliation(s)
- Zahra Heidari
- Department of Ophthalmology, Bu-Ali Sina Hospital, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Mehrdad Mohammadpour
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
- Department of Ophthalmology, Farabi Eye Hospital and Eye Research Center, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Fedra Hajizadeh
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Akbar Fotouhi
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Hassan Hashemi
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
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11
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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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12
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Zhang X, Ding L, Sun L, Sun B, Huang Y, Qian Y, Zhou X. Assessment of Keratoconus Risk in Very Asymmetric Ectasia Using Corneal Tomographic and Biomechanical Parameters. Clin Ophthalmol 2023; 17:3569-3577. [PMID: 38026612 PMCID: PMC10676676 DOI: 10.2147/opth.s439739] [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: 09/11/2023] [Accepted: 11/14/2023] [Indexed: 12/01/2023] Open
Abstract
Purpose To investigate the relationship between corneal tomographic or biomechanical parameters and risk of keratoconus in very asymmetric ectasia (VAE). Methods This retrospective case-control single-centre study included patients with VAE and normal controls. The VAE group had clinical ectasia in one eye and normal topography (VAE-NT) in the fellow eye; VAE-NT eyes were selected for analysis. The control group was selected from corneal refractive surgery candidates; the right eye was enrolled. Scheimpflug-based corneal tomography (Pentacam) and corneal biomechanical assessment (Corvis ST) were performed. Univariate and multivariable logistic regression were performed using Cox proportional hazards models to evaluate keratoconus-associated risk factors. A two-piecewise linear regression model was applied to examine the threshold effect of selected vital paragmeters on the risk of keratoconus according to a smoothing plot. Results Threshold effect between tomographic integration and risk of keratoconus was observed. Discrepancy between the central corneal thickness and thinnest corneal thickness (discrepancy CCT vs TCT) greater than 5 μm, discrepancy between the apex corneal thickness and thinnest corneal thickness (discrepancy ACT vs TCT) greater than 3 μm, vector distance between CCT and TCT (distance CCT vs TCT) greater than 0.65 mm indicated a significant increased risk of keratoconus. Risk of keratoconus decreased when distance CCT vs TCT was less than 0.65 mm. Conclusion Discrepancy CCT vs TCT, discrepancy ACT vs TCT, and distance CCT vs TCT can be used as indicators for risk assessment of early keratoconus.
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Affiliation(s)
- Xiaoyu Zhang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People’s Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
| | - Lan Ding
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People’s Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
| | - Ling Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People’s Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
| | - Bingqing Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People’s Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
| | - Yangyi Huang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People’s Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
| | - Yishan Qian
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People’s Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People’s Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
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Lu NJ, Hafezi F, Koppen C, Alió Del Barrio JL, Aslanides IM, Awwad ST, Ní Dhubhghaill S, Pineda R, Torres-Netto EA, Wang L, Chen SH, Cui LL, Rozema JJ. New keratoconus staging system based on OCT. J Cataract Refract Surg 2023; 49:1098-1105. [PMID: 37531392 DOI: 10.1097/j.jcrs.0000000000001276] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 07/25/2023] [Indexed: 08/04/2023]
Abstract
PURPOSE To establish a numerical spectral-domain optical coherence tomography (SD-OCT)-based keratoconus (KC) staging system and compare it with existing KC staging systems. SETTING Eye Hospital of Wenzhou Medical University, Wenzhou, China. DESIGNS Retrospective case-control study. METHODS Scheimpflug tomography, air-puff tonometry, and SD-OCT were performed on 236 normal and 331 KC eyes. All SD-OCT-derived parameters of the corneal epithelium and stroma were evaluated based on their receiver operating characteristic (ROC) curves, area under the curve (AUC), sensitivity, and specificity to discriminate between normal and KC eyes. The best performing parameters were subsequently used to create an OCT-based staging system, which was compared with existing tomographic and biomechanical staging systems. RESULTS 236 eyes from 236 normal patients and 331 eyes from 331 KC patients of different stages were included. The highest ranked AUC ROC SD-OCT parameters, derived from stroma and epithelium, were stroma overall minimum thickness (ST: AUC 0.836, sensitivity 90%, specificity 67%) and epithelium overall SD (EP: AUC 0.835, sensitivity 75%, specificity 78%). A numerical SD-OCT staging system called STEP including 2 parameters-"ST" and "EP"-with 5 stages was proposed. CONCLUSIONS The new SD-OCT-based KC staging system is the first to take the epithelium with its sublayer stroma information into account, showing a strong agreement to the existing staging systems. This system could be incorporated into daily practice, potentially leading to an overall improvement in KC treatment and follow-up management.
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Affiliation(s)
- Nan-Ji Lu
- From the Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium (Lu, Koppen, Ní Dhubhghaill, Rozema); National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China (Lu, Hafezi, Aslanides, Chen, Cui); State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, China (Lu, Chen, Cui); Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China (Lu, Wang); ELZA Institute, Dietikon, Switzerland (Lu, Hafezi, Torres-Netto); Ocular Cell Biology Group, Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Switzerland (Hafezi, Torres-Netto); Faculty of Medicine, University of Geneva, Geneva, Switzerland (Hafezi, Torres-Netto); Department of Ophthalmology, University of Southern California, Los Angeles, California (Hafezi); Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium (Koppen, Rozema); Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain (Alió del Barrio); Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain (Alió del Barrio); Emmetropia Mediterranean Eye Institute, Heraklion, Crete, Greece (Aslanides); The American University of Beirut Medical Center, Beirut, Lebanon (Awwad); The Department of Ophthalmology, Brussels University Hospital, Brussels, Belgium (Ní Dhubhghaill); The faculty of Health Sciences and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium (Ní Dhubhghaill); Department of Ophthalmology, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts (Pineda)
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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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15
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Deshmukh R, Shrivastava AK, Vaddavalli PK. Prevailing practice patterns in keratoconus among Indian ophthalmologists. Indian J Ophthalmol 2023; 71:3229-3234. [PMID: 37602613 PMCID: PMC10565949 DOI: 10.4103/ijo.ijo_595_23] [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: 02/27/2023] [Revised: 06/19/2023] [Accepted: 06/30/2023] [Indexed: 08/22/2023] Open
Abstract
Objective The past few years have seen a rapid advancement in the management of keratoconus (KC). However, there is no prescribed standard of care for the management of KC. This study evaluated the prevailing practice patterns among Indian ophthalmologists in the diagnosis and treatment of KC via an online survey. Methods This was a survey-based cross-sectional study in which a questionnaire (Supplement 1) was created. Questions pertaining to the practicing experience, setting of practice, and training background were asked in addition to the investigations done and decision making in KC management. Responses were collected via Survey Monkey (Survey Monkey, Palo Alto, California, USA) and statistical analysis performed using R software (4.1.3). Results The survey was answered by 273 ophthalmologists. Pentacam was the most used topographer (195 users), followed by Orbscan (41 users), Sirius (34 users), and Galilei (3 users). The lowest limit of pachymetry for performing collagen crosslinking (CXL) was 400μ for most practitioners. More than half the respondents (50.55%) did not perform photorefractive keratectomy (PRK) or intracorneal ring segment (ICRS) implantation in a suitable patient. Accelerated 10-minute protocol (9 mW/cm2 for 10 minutes) was the most commonly (54.21%) used for CXL, followed by Dresden protocol (3 mW/cm2 for 30 minutes) (36.63%). When a patient was unsuitable for CXL, 55.31% surgeons advise contact lens (CL) trial, 35.16% surgeons advise keratoplasty, 26.74% surgeons perform stromal augmentation, and 7.69% surgeons advise spectacle correction. Corneal scar was the most common indication (49.45%) for performing keratoplasty. Conclusion Topography remains the most used diagnostic modality for initial diagnosis. Optical coherence tomography and epithelial mapping are increasingly being used for early diagnosis of KC. Not all ophthalmologists were comfortable performing ICRS or PRK. When patients are unsuitable for CXL, CL trial remains the most frequently advised option followed by keratoplasty.
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Affiliation(s)
- Rashmi Deshmukh
- Cataract and Refractive Services, LV Prasad Eye Institute, Hyderabad, Telangana, India
| | - Alok Kumar Shrivastava
- Cataract and Refractive Services, LV Prasad Eye Institute, Hyderabad, Telangana, India
- Sri Innovation and Research Foundation, Ghaziabad, Uttar Pradesh, India
| | - Pravin Krishna Vaddavalli
- Cataract and Refractive Services, LV Prasad Eye Institute, Hyderabad, Telangana, India
- Shantilal Sanghvi Eye Institute, Hyderabad, Telangana, India
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16
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Sahebjada S, Chan E, Sutton G, Pang CPC, Kerdraon Y, Natarajan S, Meteoukki W, Ang A, Daniell M, Baird PN. Keratoconus International Consortium (KIC)- advancing keratoconus research. BMC Ophthalmol 2023; 23:337. [PMID: 37501133 PMCID: PMC10375634 DOI: 10.1186/s12886-023-03087-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 07/16/2023] [Indexed: 07/29/2023] Open
Abstract
CLINICAL RELEVANCE The Keratoconus International Consortium (KIC) will allow better understanding of keratoconus. BACKGROUND Keratoconus is a disorder characterised by corneal elevation and thinning, leading to reduced vision. The current gaps in understanding of this disease will be discussed and the need for a multi-pronged and multi-centre engagement to enhance our understanding of keratoconus will be highlighted. DESIGN KIC has been established to address the gaps in our understanding of keratoconus with the aim of collecting baseline as well as longitudinal data on several fields. PARTICIPANTS Keratoconus and control (no corneal condition) subjects from different sites globally will be recruited in the study. METHODS KIC collects data using an online, secure database, which enables standardised data collection at member sites. Data fields collected include medical history, clinical features, quality of life and economic burden questionnaires and possible genetic sample collection from patients of different ethnicities across different geographical locations. RESULTS There are currently 40 Australian and international clinics or hospital departments who have joined the KIC. Baseline data has so far been collected on 1130 keratoconus patients and indicates a median age of 29.70 years with 61% being male. A total of 15.3% report a positive family history of keratoconus and 57.7% self-report a history of frequent eye rubbing. CONCLUSION The strength of this consortium is its international, collaborative design and use of a common data collection tool. Inclusion and analyses of cross-sectional and longitudinal data will help answer many questions that remain in keratoconus, including factors affecting progression and treatment outcomes.
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Affiliation(s)
- Srujana Sahebjada
- Centre for Eye Research Australia, Level 7, 32 Gisborne St, East Melbourne, Victoria, 3002, Australia.
- Department of Surgery, Ophthalmology, The University of Melbourne, Melbourne, Australia.
| | - Elsie Chan
- Centre for Eye Research Australia, Level 7, 32 Gisborne St, East Melbourne, Victoria, 3002, Australia
- Department of Surgery, Ophthalmology, The University of Melbourne, Melbourne, Australia
- Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Gerard Sutton
- Sydney Medical School, The University of Sydney, Sydney, Australia
- NSW Tissue Banks, Sydney, Australia
| | | | - Yves Kerdraon
- Sydney Medical School, The University of Sydney, Sydney, Australia
- Envision Eye Centre, Sydney, Australia
| | | | - Wafaa Meteoukki
- Molecular and Cellular Genetics Laboratory, Oran University of Science and Technology - Mohamed Boudiaf (USTOMB), Oran, Algeria
| | | | - Mark Daniell
- Centre for Eye Research Australia, Level 7, 32 Gisborne St, East Melbourne, Victoria, 3002, Australia
- Department of Surgery, Ophthalmology, The University of Melbourne, Melbourne, Australia
- Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Paul N Baird
- Department of Surgery, Ophthalmology, The University of Melbourne, Melbourne, Australia
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Nobl M, Gerhardt M, Kassumeh S, Mohr N, Mayer W, Dirisamer M, Priglinger S, Luft N. [Steering clear of "corneal red disease"-epithelial thickness mapping for differential diagnosis of corneal ectatic disease]. DIE OPHTHALMOLOGIE 2023; 120:430-436. [PMID: 35925332 DOI: 10.1007/s00347-022-01663-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 05/04/2022] [Accepted: 05/11/2022] [Indexed: 04/29/2023]
Affiliation(s)
- Matthias Nobl
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Maximilian Gerhardt
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Stefan Kassumeh
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Niklas Mohr
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Wolfgang Mayer
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Martin Dirisamer
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
- Auge-Laser-Chirurgie, Linz, Österreich
| | - Siegfried Priglinger
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
- Auge-Laser-Chirurgie, Linz, Österreich
| | - Nikolaus Luft
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland.
- Auge-Laser-Chirurgie, Linz, Österreich.
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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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19
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Comprehensive Assessment of Corvis ST Biomechanical Indices in Normal and Keratoconus Corneas with Reference to Corneal Enantiomorphism. J Clin Med 2023; 12:jcm12020690. [PMID: 36675618 PMCID: PMC9863401 DOI: 10.3390/jcm12020690] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/06/2023] [Accepted: 01/13/2023] [Indexed: 01/18/2023] Open
Abstract
The aim of this study was to assess Corvis ST biomechanical indices in reference to corneal enantiomorphism. In a prospective observational cohort study, 117 eyes from 63 patients with normal or keratoconus corneas were assessed by three independent observers. In the control group (n = 62), no significant differences were observed between the three observers for all indices. The best reproducibility was obtained with pachymetry and the weakest with CBI. All indices but CBI and arc length featured COV < 10%. All indices except the PD and SSI correlated with pachymetry; all but Rad correlated with IOP. The comparison of the thinnest with the thickest corneas showed no significant differences for any index except pachymetry. In the keratoconus group (n = 55), loss of corneal enantiomorphism was confirmed for all indices except the arc length, velocity, and PD. Significant differences between both groups were found for all indices, even after adjustment for pachymetry and intraocular pressure. The CBI featured the best accuracy (92%), sensitivity (91%), and graphical relevance for keratoconus diagnosis. However, its reproducibility was weak in normal corneas and was strongly dependent on corneal thickness. The SSI was independent of corneal thickness, highly reproducible, and provided the expected enantiomorphism characteristics in both groups, making it a relevant biomarker of biomechanical corneal behavior.
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Elessawy K, Azzam S, Salama T, Eissa S. Combined scheimpflug and optical coherence tomography imaging in screening of keratoconus in children with Down syndrome. DELTA JOURNAL OF OPHTHALMOLOGY 2023. [DOI: 10.4103/djo.djo_59_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
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Yücekul B, Dick HB, Taneri S. Systematic detection of keratoconus in OCT: corneal and epithelial thickness maps. J Cataract Refract Surg 2022; 48:1360-1365. [PMID: 35714335 DOI: 10.1097/j.jcrs.0000000000000990] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/08/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE To detect keratoconus (KC) only by analyzing the corneal and epithelial map parameters and patterns in optical coherence tomography (OCT). SETTING Tertiary care refractive surgery center. DESIGN Retrospective data collection. METHODS Corneal and epithelial thickness maps of normal, manifest, and subclinical keratoconic eyes (according to the Belin-Ambrosio display, Pentacam) were evaluated using spectral-domain OCT (Zeiss Cirrus 5000 HD). A new 2-step decision tree was developed based on previous studies with another OCT device. In the first step, if at least 1 of the 4 independent parameters (pachymetry minimum, pachymetry minimum-median, pachymetry superonasal-inferotemporal, and epithelial superonasal-inferotemporal) overruns the cutoff values, the eye was suspicious for KC. In the second step, if the epithelial map showed concentric thinning and the thinnest point of the cornea and epithelium is coincident, the eye was classified as keratoconic. RESULTS 172 manifest keratoconic eyes (108 patients), 21 subclinical keratoconic eyes (20 patients), and 172 normal eyes (90 age-matched participants) were included in this study. Step 1 captured 100% of manifest and subclinical keratoconic eyes. Step 2 ruled out all suspicious but normal cases and, falsely, 2 subclinical keratoconic eyes. Our 2-step decision tree reached 100% specificity, 100% sensitivity in manifest KC, and 90.4% sensitivity in subclinical KC. CONCLUSIONS Pachymetric and epithelial map parameters and patterns in OCT can be used in the diagnosis of KC, including subclinical cases, yielding a high level of agreement with the commonly used diagnostic reference, the Belin-Ambrosio display. Further improvements by refining our algorithm and including an automated evaluation in the software are desirable.
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Affiliation(s)
- Burcu Yücekul
- From the Department of Ophthalmology, Haseki Training and Research Hospital, Istanbul, Turkey (Yücekul); Ruhr University, Bochum, Germany (Dick, Taneri); Zentrum für Refraktive Chirurgie, Augenzentrum am St. Franziskus Hospital, Muenster, Germany (Taneri)
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Santhiago MR, Stival LR, Araujo DC, Kara-Junior N, Toledo MC. Role of Corneal Epithelial Measurements in Differentiating Eyes with Stable Keratoconus from Eyes that Are Progressing. OPHTHALMOLOGY SCIENCE 2022; 3:100256. [PMID: 36579337 PMCID: PMC9791590 DOI: 10.1016/j.xops.2022.100256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022]
Abstract
Purpose To evaluate measures of corneal epithelium in eyes that showed documented signs of keratoconus (KC) progression and compare with stable eyes and healthy controls. Also, to determine the correlation of these epithelial parameters with maximum keratometry (K max) and pachymetry. Design Prospective, observational, comparative study. Participants One-hundred and fifty eyes from 150 patients. The study included 50 eyes from patients with documented KC progression, 50 eyes with stable KC, and 50 clinically normal eyes to serve as controls. Methods A spectral-domain (SD)-OCT imaging was obtained in all eyes, and mean values were compared between the groups. The correlation of epithelial parameters with K max and thinnest pachymetry was also investigated. Main Outcome Measures For the purposes of this study, the epithelial measures maximum, minimum, superior, and inferior values as well as the difference between the minimum and maximum (min-max) and epithelial standard deviation were considered, obtained from SD-OCT and compared between groups. Measurements of the thinnest point and min-max in pachymetry were also recorded. Results The only epithelial parameter that presented a statistically significant difference between stable and progressive KC was epithelium min-max. Although stable KC presented epithelium min-max mean values of -18.2 ± 6.6, progressive KC eyes presented mean values of -23.4 ± 10.3 (P < 0.0001). Epithelial maximum (P = 0.16), minimum (P = 0.25), superior (P = 0.28), inferior (P = 0.23), and standard deviation (P = 0.25) values were not significantly different between stable and progressive eyes. Difference min-max pachymetry points in stable (-108.3 ± 33.5) and progressive KC (-115.2 ± 56.0) were not significantly different (P = 0.723). There was no significant correlation between epithelium min-max with corneal thinning (P = 0.39) or K max (P = 0.09) regardless of disease progression. Conclusions Epithelial measures are useful to identify KC eyes that are progressing; the parameters that measure the difference between min-max epithelium points were significantly different between stable and progressive groups, unlike this difference in pachymetry. Finally, this epithelial parameter seems to be independent of corneal thinning and K max. Financial Disclosures Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Marcony R. Santhiago
- Department of Ophthalmology at University of Sao Paulo, Sao Paulo, Brazil,Correspondence: Marcony R. Santhiago, MD, PhD, Instituto Central. 255 Enéas de Carvalho Aguiar AV.–Ophthalmology Department - Federal University of Sao Paulo, Sao Paulo, Brazil.
| | - Larissa R. Stival
- Department of Ophthalmology at University of Sao Paulo, Sao Paulo, Brazil,Department of Ophthalmology, Federal University of Goias, Goiania, Brazil
| | - Daniella C. Araujo
- Department of Computer Science, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Newton Kara-Junior
- Department of Ophthalmology at University of Sao Paulo, Sao Paulo, Brazil
| | - Marcia C. Toledo
- Department of Ophthalmology, Federal University of Goias, Goiania, Brazil
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Levy A, Georgeon C, Knoeri J, Tourabaly M, Leveziel L, Bouheraoua N, Borderie VM. Corneal Epithelial Thickness Mapping in the Diagnosis of Ocular Surface Disorders Involving the Corneal Epithelium: A Comparative Study. Cornea 2022; 41:1353-1361. [PMID: 35349542 PMCID: PMC9555759 DOI: 10.1097/ico.0000000000003012] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 10/25/2021] [Accepted: 12/05/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this study was to analyze the role of corneal epithelial thickness (ET) mapping provided by spectral domain optical coherence tomography in the diagnosis of ocular surface disorders (OSDs) involving the corneal epithelium. DESIGN This was a retrospective comparative study. METHODS Institutional settings are as follows. Study population includes 303 eyes with an OSD and 55 normal eyes (controls). Observation procedures include spectral domain optical coherence tomography with epithelial mapping in the central 6 mm. Main outcome measures include ET map classification (normal, doughnut, spoke-wheel, localized/diffuse, and thinning/thickening patterns) and ET data and statistics (minimum, maximum, and SD). A quantitative threshold was determined with receiver operating curves to distinguish pathological from normal corneas. Sensitivity and specificity of classification and quantitative data were calculated using all eyes to assess the ability to distinguish corneas with a given corneal disorder from other conditions. RESULTS Classification of full agreement between 3 readers was obtained in 75.4% to 99.4% of cases. Main OSD features were keratoconus (135 eyes), doughnut pattern (sensitivity/specificity = 56/94%), and max-min ET ≥ 13 μm (84/43%); limbal deficiency (56 eyes), spoke-wheel pattern (66/98%), and max-min ET ≥ 14 μm (91/59%); epithelial basement membrane dystrophy (55 eyes), inferior thickening pattern (55/92%), and central ET > 56 μm (53/81%); dry eye (21 eyes), superior thinning pattern (67/88%), and minimal ET ≤ 44 μm (86/48%); pterygium (10 eyes), nasal thickening pattern (100/86%), and nasal ET > 56 μm (80/71%); and in situ carcinoma (11 eyes), max ET > 60 μm (91/60%), and ET SD >5 μm (100/58%). CONCLUSIONS The epithelial map pattern recognition combined with quantitative analysis of ET is relevant for the diagnosis of OSDs and for distinguishing various OSDs from each other. Deep learning analysis of big data could lead to the fully automated diagnosis of these disorders.
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Affiliation(s)
- Arielle Levy
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.
| | - Cristina Georgeon
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.
| | - Juliette Knoeri
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.
| | - Moïse Tourabaly
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.
| | - Loïc Leveziel
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.
| | - Nacim Bouheraoua
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.
| | - Vincent M. Borderie
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.
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Reinstein DZ, Archer TJ, Vida RS. Epithelial thickness mapping for corneal refractive surgery. Curr Opin Ophthalmol 2022; 33:258-268. [PMID: 35779050 DOI: 10.1097/icu.0000000000000867] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW As more devices become available that offer corneal epithelial thickness mapping, this is becoming more widely used for numerous applications in corneal refractive surgery. RECENT FINDINGS The epithelial thickness profile is nonuniform in the normal eye, being thinner superiorly than inferiorly and thinner temporally than nasally. Changes in the epithelial thickness profile are highly predictable, responding to compensate for changes in the stromal curvature gradient, using the eyelid as an outer template. This leads to characteristic changes that can be used for early screening in keratoconus, postoperative monitoring for early signs of corneal ectasia, and for determining whether further steepening can be performed without the risk of apical syndrome following primary hyperopic treatment. Compensatory epithelial thickness changes are also a critical part of diagnosis in irregular astigmatism as these partially mask the stromal surface irregularities. The epithelial thickness map can then be used to plan a trans-epithelial PRK treatment for cases of irregularly irregular astigmatism. Other factors can also affect the epithelial thickness profile, including dry eye, anterior basement membrane dystrophy and eyelid ptosis. SUMMARY Epithelial thickness mapping is becoming a crucial tool for refractive surgery, in particular for keratoconus screening, ectasia monitoring, hyperopic treatment planning, and therapeutic diagnosis and treatment.
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Affiliation(s)
- Dan Z Reinstein
- Reinstein Vision
- London Vision Clinic, London, UK
- Department of Ophthalmology, Columbia University Medical Center, New York, USA
- Sorbonne Université, Paris, France
- School of Biomedical Sciences, University of Ulster, Coleraine, UK
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Detection of subclinical keratoconus using a novel combined tomographic and biomechanical model based on an automated decision tree. Sci Rep 2022; 12:5316. [PMID: 35351951 PMCID: PMC8964676 DOI: 10.1038/s41598-022-09160-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 03/16/2022] [Indexed: 11/09/2022] Open
Abstract
Early detection of keratoconus is a crucial factor in monitoring its progression and making the decision to perform refractive surgery. The aim of this study was to use the decision tree technique in the classification and prediction of subclinical keratoconus (SKC). A total of 194 eyes (including 105 normal eyes and 89 with SKC) were included in the double-center retrospective study. Data were separately used for training and validation databases. The baseline variables were derived from tomography and biomechanical imaging. The decision tree models were generated using Chi-square automatic interaction detection (CHAID) and classification and regression tree (CART) algorithms based on the training database. The discriminating rules of the CART model selected metrics of the Belin/Ambrósio deviation (BAD-D), stiffness parameter at first applanation (SPA1), back eccentricity (Becc), and maximum pachymetric progression index in that order; On the other hand, the CHAID model selected BAD-D, deformation amplitude ratio, SPA1, and Becc. Further, the CART model allowed for discrimination between normal and SKC eyes with 92.2% accuracy, which was higher than that of the CHAID model (88.3%), BAD-D (82.0%), Corvis biomechanical index (CBI, 77.3%), and tomographic and biomechanical index (TBI, 78.1%). The discriminating performance of the CART model was validated with 92.4% accuracy, while the CHAID model was validated with 86.4% accuracy in the validation database. Thus, the CART model using tomography and biomechanical imaging was an excellent model for SKC screening and provided easy-to-understand discriminating rules.
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Asroui L, Dupps WJ, Randleman JB. Determining the Utility of Epithelial Thickness Mapping in Refractive Surgery Evaluations. Am J Ophthalmol 2022; 240:125-134. [PMID: 35247335 DOI: 10.1016/j.ajo.2022.02.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/18/2022] [Accepted: 02/20/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE To determine the impact of corneal epithelial thickness maps on screening for refractive surgery candidacy in a single refractive surgical practice. DESIGN Comparison of screening methods. METHODS A total of 100 consecutive patients who presented for refractive surgery screening were evaluated. For each patient, screening based on Scheimpflug tomography, clinical data, and patient history was performed and a decision on eligibility for laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE)was independently made by 2 masked examiners. Examiners were then shown patients' epithelial thickness maps derived from optical coherence tomography (OCT). The percentage of screenings that changed after evaluating the epithelial thickness maps, with regard to candidacy for surgery, and ranking of surgical procedures from most to least favorable was determined. RESULTS Candidacy for corneal refractive surgery changed in 16% of patients after evaluation of the epithelial thickness maps, with 10% of patients screened in and 6% screened out. Surgery of choice changed for 16% of patients, and the ranking of surgical procedures from most to least favorable changed for 25% of patients. A total of 11% of patients gained eligibility for LASIK, whereas 8% lost eligibility for LASIK. No significant difference was found between the evaluations of the 2 examiners. CONCLUSIONS Epithelial thickness mapping derived from optical coherence tomography imaging of the cornea altered candidacy for corneal refractive surgery, as well as choice of surgery, in a substantial percentage of patients in our practice, and was thus a valuable tool for screening evaluations. Overall, the use of epithelial thickness maps resulted in screening in a slightly larger percentage of patients for corneal refractive surgery.
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Affiliation(s)
- Lara Asroui
- From the Cole Eye Institute (L.A., W.J.D., J.B.R.), Department of Biomedical Engineering, Lerner Research Institute (W.J.D.), Cleveland Clinic, Department of Biomedical Engineering, Case Western Reserve University (W.J.D.), and the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (W.J.D, J.B.R) Cleveland, Ohio, USA
| | - William J Dupps
- From the Cole Eye Institute (L.A., W.J.D., J.B.R.), Department of Biomedical Engineering, Lerner Research Institute (W.J.D.), Cleveland Clinic, Department of Biomedical Engineering, Case Western Reserve University (W.J.D.), and the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (W.J.D, J.B.R) Cleveland, Ohio, USA
| | - J Bradley Randleman
- From the Cole Eye Institute (L.A., W.J.D., J.B.R.), Department of Biomedical Engineering, Lerner Research Institute (W.J.D.), Cleveland Clinic, Department of Biomedical Engineering, Case Western Reserve University (W.J.D.), and the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (W.J.D, J.B.R) Cleveland, Ohio, USA.
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Abusamak M. Corneal Epithelial Mapping Characteristics in Normal Eyes Using Anterior Segment Spectral Domain Optical Coherence Tomography. Transl Vis Sci Technol 2022; 11:6. [PMID: 35258560 PMCID: PMC8914566 DOI: 10.1167/tvst.11.3.6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The detailed mapping characteristics of the corneal epithelial thickness (CET) in normal eyes from a Middle Eastern population were investigated in relation to age, sex, intraocular pressure, and keratometric power (K). Methods A retrospective cross-sectional and analytical study was conducted using spectral domain optical coherence tomography (OCT). We calculated the CET in 124 subjects in 17 zones within a 6 mm circle. Exclusion criteria included subjects with dry eyes, keratoconus, previous eye surgery, glaucoma, and irregular corneas. Results A total of 124 individuals was composed of 64 males and 60 females. The mean age of this population was 45.52, ranging from 18 to 79 years. The central CET was thicker in the central 2 mm than the other zones of the cornea except the nasal, inferior-nasal, inferior and inferior-temporal zones, respectively. Males have thicker CET than females in all zones except in the peripheral nasal zone. We found a positive and significant correlation between age and CET in the central, superior-peripheral, inferior-paracentral, and inferior-temporal paracentral zones. Additionally, a medium-positive correlation was detected between increasing age and the variability of epithelial spectral domain in different zones. No link between CET and intraocular pressure was found. Conclusions This study analyzed 17 CET zones within the central 6 mm, where the central epithelium is resistant to aging. The CET was thinner superiorly than inferiorly. This may help in decision-making in refractive procedures and in the prediction of corneal diseases. Translational Relevance OCT novel algorithms are noninvasive methods for measuring CET and have been demonstrated to be useful in refractive surgery planning and follow-up, as well as a robust tool for diagnosing potential corneal ectasia.
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Affiliation(s)
- Mohammad Abusamak
- Department of Surgery, School of Medicine, Al-Balqa Applied University, Al-Salt, Jordan.,Amman Eye Clinic, Amman, Jordan
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Pavlatos E, Harkness B, Louie D, Chamberlain W, Huang D, Li Y. Differentiating Between Contact Lens Warpage and Keratoconus Using OCT Maps of Corneal Mean Curvature and Epithelial Thickness. J Refract Surg 2022; 38:112-119. [PMID: 35156455 PMCID: PMC8870421 DOI: 10.3928/1081597x-20211116-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To formulate an Epithelial Modulation index to differentiate between eyes with contact lens warpage and keratoconus. METHODS Normal eyes and eyes with either contact lens warpage or keratoconus were scanned by a Fourier-domain optical coherence tomography (OCT) system. Maps of epithelial thickness and anterior surface mean curvature were generated and converted to deviation maps by subtracting the average maps from a healthy population. The Epithelial Modulation index was defined as the covariance between the two types of deviation maps. A logistic regression model was used to classify eyes as non-keratoconus (normal or warp-age) or keratoconus (manifest, subclinical, or forme fruste). RESULTS The average Epithelial Modulation index value for normal eyes was -0.6 ± 1.0 µm/m. Eyes with keratoconus were characterized by coincident high anterior surface mean curvature and low epithelial thickness, resulting in a high Epithelial Modulation index (manifest: 103.0 ± 82.9 µm/m, subclinical: 37.0 ± 23.0 µm/m, forme fruste: 7.3 ± 13.2 µm/m). The Epithelial Modulation index was closer to normal for eyes with warpage (-1.9 ± 4.0 µm/m). The classification accuracy of the Epithelial Modulation index during five-fold cross-validation of the logistic regression model was 100 ± 0% for normal eyes and 99.0 ± 2.0% for eyes with warpage. The accuracy was 100 ± 0%, 100 ± 0%, and 53.1 ± 1.5% for the manifest, subclinical, and forme fruste keratoconus groups, respectively. CONCLUSIONS The Epithelial Modulation index is useful in distinguishing eyes with secondary epithelial modulation (keratoconus) from those with primary epithelial deformation (contact lens-related warpage). [J Refract Surg. 2022;38(2):112-119.].
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Heidari Z, Hashemi H, Mohammadpour M, Momeni-Moghaddam H, Khabazkhoob M. Distribution pattern of total corneal thickness in keratoconus versus normal eyes using an optical coherence tomography. J Curr Ophthalmol 2022; 34:216-222. [PMID: 36147258 PMCID: PMC9487006 DOI: 10.4103/joco.joco_198_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 01/02/2022] [Accepted: 01/06/2022] [Indexed: 11/16/2022] Open
Abstract
Purpose: To evaluate the total corneal thickness distribution pattern using a high-resolution spectral-domain optical coherence tomography (HR SD-OCT) for distinguishing normal eyes from keratoconus (KCN). Methods: One hundred and forty-four patients were enrolled in three groups (55 normal, 45 mild KCN, and 44 moderate-to-severe KCN eyes) in this prospective diagnostic test study. Total corneal thickness was measured in 8 semi-meridians using HR SD-OCT (Heidelberg Engineering, Heidelberg, Germany) in 5 and 7 mm zones. The central corneal thickness (CCT), corneal focal thinning (minimum thickness [Min], min minus median and maximum [Min-Med, Min-Max]), and asymmetry indices (inferior minus superior [I-S] and supranasal minus infratemporal [SN-IT]) were calculated. One-way analysis of variance and the area under the receiver operating characteristic curve (AUC) were used for the analysis. Results: Thinner CCT, lower Min thickness, more negative Min-Max, Min-Med, and greater I-S and SN-IT were found in KCN eyes compared to the control group (P < 0.001). The inferior and IT semi-meridians were the thinnest locations in KCN cases in the 5 mm central zone (P < 0.001). CCT followed by Min-Med had the highest discriminative ability for differentiating mild KCN (AUC, sensitivity and specificity: 0.822, 87.0%, 60.37% and 0.805, 82.93%, 66.0%, respectively) and moderate-to-severe KCN (0.902, 87.82%, 73.08% and 0.892, 85.37%, and 78.85%, respectively) from normal corneas. Conclusion: The inferior and IT sectors of the cornea with the largest thickness changes in the 5 mm zone are the most common thinning sites in keratoconic corneas, and CCT and Min-Med are the most sensitive indices for the diagnosis of KCN.
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December consultation #5. J Cataract Refract Surg 2021; 47:1601-1602. [PMID: 34846341 DOI: 10.1097/01.j.jcrs.0000805124.76974.4b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Flockerzi E, Vinciguerra R, Belin MW, Vinciguerra P, Ambrósio R, Seitz B. Combined biomechanical and tomographic keratoconus staging: Adding a biomechanical parameter to the ABCD keratoconus staging system. Acta Ophthalmol 2021; 100:e1135-e1142. [PMID: 34655452 DOI: 10.1111/aos.15044] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/22/2021] [Accepted: 09/22/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE This retrospective cross-sectional study evaluated the potential of an additional biomechanical parameter 'E' as an addition to the tomographic ABCD ectasia/keratoconus (KC) staging. METHODS The Corvis Biomechanical Factor (CBiF) represents the modified linear term of the Corvis Biomechanical Index (CBI) developed based on 448 KC corneas from the Homburg Keratoconus Center (HKC). The CBiF range was divided into five stages (E0 to E4) to create a grading system according to the ABCD stages. Stage E0 was characterized by values smaller than the 2.5 percentile. The thresholds were created by dividing the CBiF range between the 2.5 and 97.5 percentiles into four groups of equal values (E1-E4). The frequency distribution of 'E' was analysed and independently validated based on another 860 KC corneas dataset from Milano and Rio de Janeiro (MR). The relationship between 'E' and the ABCD staging was analysed by cross-tabulation. The specificity of 'E' was assessed based on healthy controls (112|851) from both datasets (HKC|MR). RESULTS 'E' was normally distributed with E0 = 37|30, E1 = 86|200, E2 = 155|354, E3 = 101|206, E4 = 69|70 in the KC group and 96.4%|90.5% of the controls classified E0 in the HKC|MR dataset, respectively. Cross-tabulation revealed that 'E' was most comparable to posterior corneal curvature ('B') in both datasets, while showing a trend towards more advanced stages in comparison to anterior corneal curvature ('A') and thinnest corneal thickness ('C'). CONCLUSION The novel Corvis-derived parameter 'E' provides a biomechanical staging for ectasia/KC potentially enhancing the ABCD staging and may detect abnormalities before tomographic changes, which requires further studies.
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Affiliation(s)
- Elias Flockerzi
- Department of Ophthalmology Saarland University Medical Center Homburg Germany
| | - Riccardo Vinciguerra
- Humanitas San Pio X Hospital Milan Italy
- School of Engineering University of Liverpool Liverpool UK
| | | | - Paolo Vinciguerra
- Department of Biomedical Sciences Humanitas University Milan Italy
- Humanitas Clinical and Research Center – IRCCS Rozzano Italy
| | - Renato Ambrósio
- Department of Ophthalmology Federal University of the State of Rio de Janeiro Rio de Janeiro Brazil
| | - Berthold Seitz
- Department of Ophthalmology Saarland University Medical Center Homburg Germany
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Corneal and Epithelial Thickness Mapping: Comparison of Swept-Source- and Spectral-Domain-Optical Coherence Tomography. J Ophthalmol 2021; 2021:3444083. [PMID: 34650817 PMCID: PMC8510821 DOI: 10.1155/2021/3444083] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022] Open
Abstract
Objective To compare the results and repeatability of the corneal thickness (CT) and epithelial thickness (ET) maps provided by Enhanced Spectral-Domain-Optical Coherence Tomography with those of Spectral-Domain-OCT in normal eyes. Methods 30 normal eyes of 30 patients were assessed by 3 trained operators with ESD-OCT and SD-OCT. Results The central and minimum ET obtained with both devices were correlated: central ET, r = 0.86, p < 0.05; minimum ET, r = 0.72, p < 0.05. Compared with SD-OCT, ESD-OCT tended to underestimate these figures by 1.4 and 1.9 μm on average. The central and minimum CT obtained with both devices were strongly correlated: central CT, r = 0.994, p < 0.05; minimum CT, r = 0.995, p < 0.05. ESD-OCT tended to overestimate these figures by 11 and 14 μm on average. Repeatability was good for both devices with a mean coefficient of variation of measurements <6% for ET and <2% for CT. Interoperator variability (standard deviation and COV) was significantly higher for ESD-OCT than for SD-OCT for all local epithelial thicknesses and significantly lower for the central CT and several local corneal thicknesses, whereas no significant differences between both technologies were found for the central and minimum ET and the minimum CT. Conclusion ESD-OCT and SD-OCT provide reproducible measurements of CT and ET in normal corneas with a strong correlation between both technologies. However, both technologies are not interchangeable when the main thickness parameters (i.e., central and minimum CT and minimum ET) are used for diagnosing early keratoconus or calculating the expected residual stromal bed thickness before corneal refractive surgery or anterior lamellar keratoplasty.
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Diagnostic Value of Corneal Epithelial and Stromal Thickness Distribution Profiles in Forme Fruste Keratoconus and Subclinical Keratoconus. Cornea 2021; 40:61-72. [PMID: 32769675 DOI: 10.1097/ico.0000000000002435] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To assess the diagnostic values of corneal epithelial and stromal thickness distribution characteristics in forme fruste keratoconus (FFKC) and subclinical keratoconus (KC). METHODS This cross-sectional study was conducted at VISSUM Innovation and Miguel Hernandez University, Alicante, Spain. Twenty-seven eyes (27 subjects) with FFKC, 50 eyes (50 subjects) with subclinical KC with a best spectacle corrected distance visual acuity ≥20/20 (Snellen) (grade zero KC according to the Red Temática de Investigación Cooperativa en Salud classification), and 66 control eyes (66 subjects) were included. Epithelial and stromal thicknesses and epithelium/stroma (E/S) thickness ratio at center, thinnest point, 5-, and 8-mm circles obtained from the MS-39 device (CSO, Firenze, Italy) were compared among the control, FFKC, and subclinical KC groups. RESULTS The FFKC group had thinner 8-mm superior-nasal epithelium and higher central E/S ratio compared with the control group (P < 0.05). In the subclinical KC group, the E/S ratios in the 5-mm temporal and superior zones were higher than those in the control group (P < 0.05). The FFKC and subclinical KC groups had thinner stroma compared with the control group (P < 0.05). A two-parameter formula correctly classified 94% of the eyes with subclinical KC and 98.5% of the normals, whereas another three-parameter model had 75% sensitivity and 94.3% specificity for discriminating FFKC from normals. CONCLUSIONS This study identified different epithelial distributional and behavioral patterns in eyes with FFKC and subclinical KC. Eyes with FFKC seem to have increased central E/S ratio and asymmetric superior-nasal epithelial thinning, whereas keratometric and volumetric alterations seem to be more prominent in subclinical KC.
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Li Y, Gokul A, McGhee C, Ziaei M. Repeatability of corneal and epithelial thickness measurements with anterior segment optical coherence tomography in keratoconus. PLoS One 2021; 16:e0248350. [PMID: 34143790 PMCID: PMC8213071 DOI: 10.1371/journal.pone.0248350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 02/24/2021] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To investigate the repeatability in corneal thickness (CT) and epithelial thickness (ET) measurements using spectral domain anterior segment optical coherence tomography (AS-OCT, REVO NX, Optopol) in keratoconus, and examine the effect of corneal crosslinking (CXL) on repeatability. METHODS A cross-sectional study of 259 eyes of 212 patients with keratoconus attending the corneal disease clinic at a university hospital tertiary referral center were enrolled. Two groups were analysed: eyes with no prior history of CXL (Group A) and eyes with prior CXL (Group B). Repeatability of measurements was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CV). RESULTS In Group A, central corneal thickness (CCT) was 472.18 ± 45.41μm, and the ET was found to be the thinnest in the inferior-temporal aspect at 51.79 ± 5.97μm and thickest at the superior-nasal aspect at 56.07 ± 5.70μm. In Group B, CCT was 465.11± 42.28μm, and the ET was the thinnest at the inferior-temporal aspect at 50.63 ± 5.52μm and thickest at the superior aspect at 56.80 ± 6.39μm. When evaluating CT measurements, ICC was above 0.86 and 0.83 for Group A and Group B respectively. When evaluating ET measurements, ICC was above 0.82 for both groups. CXL had no statistically significant impact on the repeatability of measurements. CONCLUSIONS AS-OCT provides repeatable CT and ET measurements in the central and peripheral cornea in patients with keratoconus. Repeatability is not affected by a history of CXL.
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Affiliation(s)
- Ye Li
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Akilesh Gokul
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Charles McGhee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Mohammed Ziaei
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Yang Y, Pavlatos E, Chamberlain W, Huang D, Li Y. Keratoconus detection using OCT corneal and epithelial thickness map parameters and patterns. J Cataract Refract Surg 2021; 47:759-766. [PMID: 33181629 PMCID: PMC8131403 DOI: 10.1097/j.jcrs.0000000000000498] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 10/20/2020] [Indexed: 01/03/2023]
Abstract
PURPOSE To detect keratoconus using optical coherence tomography (OCT) corneal map parameters and patterns. SETTING Casey Eye Institute, Oregon Health and Science University, Portland, Oregon. DESIGN Cross-sectional observational study. METHODS A spectral-domain OCT was used to acquire corneal and epithelial thickness maps in normal, manifest keratoconic, subclinical keratoconic, and forme fruste keratoconic (FFK) eyes. A 2-step decision tree was designed. An eye will be classified as keratoconus if both decision tree conditions are met. First, at least 1 of the 4 quantitative corneal thickness (minimum, minimum-maximum, and superonasal-inferotemporal) and epithelial thickness (standard deviation) map parameters exceed cutoff values. Second, presence of both concentric thinning pattern on the epithelial thickness map and coincident thinning patterns on corneal and epithelial thickness maps by visual inspection. RESULTS The study comprised 54 eyes from 29 normal participants, 91 manifest keratoconic eyes from 65 patients, 12 subclinical keratoconic eyes from 11 patients, and 19 FFK eyes from 19 patients. The decision tree correctly classified all normal eyes (100% specificity) and had good sensitivities for detecting manifest keratoconus (97.8%), subclinical keratoconus (100.0%), and FFK (73.7%). CONCLUSIONS The 2-step decision tree provided a useful tool to detect keratoconus, including cases at early disease stages (subclinical keratoconus and FFK). OCT corneal and epithelial thickness map parameters and patterns can be used in conjunction with topography to improve keratoconus screening.
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Affiliation(s)
- Yuli Yang
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University, Chongqing, China
| | - Elias Pavlatos
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
| | - Winston Chamberlain
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
| | - David Huang
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
| | - Yan Li
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
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Loureiro TDO, Rodrigues-Barros S, Lopes D, Carreira AR, Gouveia-Moraes F, Vide-Escada A, Campos NP. Corneal Epithelial Thickness Profile in Healthy Portuguese Children by High-Definition Optical Coherence Tomography. Clin Ophthalmol 2021; 15:735-743. [PMID: 33658753 PMCID: PMC7917471 DOI: 10.2147/opth.s293695] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 12/25/2020] [Indexed: 12/31/2022] Open
Abstract
Introduction and Objective To evaluate corneal epithelial thickness (ET) and corneal thickness (CT) profiles in healthy eyes of Portuguese children and provide information to establish the first normative Caucasian database for these age group. Methods Sixty healthy eyes of 60 children aged between 8 and 18 were evaluated using the Cirrus high-definition optical coherence tomography device. The average ET and CT were assessed using Cirrus Review Software with predefined concentric corneal ring-shaped zones. Specific regions of ET (central, superior, inferior, temporal, nasal, superonasal, inferotemporal, superotemporal and inferonasal) were also assessed. The mean ET, the mean CT and the difference of ET in corresponding octants were compared by gender. Correlations between central epithelial thickness (CET), age and refractive error were evaluated. Results and Discussion The average ET was lower in the peripheric zones, whereas the average CT was higher. ET was thinner in the superior area than in the inferior (p<0.05). ET was thicker in boys than in girls (p<0.05), but CT did not differ. CET was not correlated with older age or refractive error. Conclusion Optical coherence tomography analysis of ET reveals that it is thinner in the periphery, where the CT is thicker. Unlike CT, ET seems to be influenced by gender. ET profile proved to be a useful tool in keratoconus diagnosis and subclinical keratoconus detection in adults. As epithelial changes occur early in the disease and keratoconus is more aggressive in pediatric population, a normative database of ET profile could contribute to enhance early recognition of the disease in this age group.
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Affiliation(s)
| | | | - Diogo Lopes
- Ophthalmology Department, Hospital Garcia de Orta, Almada, Portugal
| | | | | | - Ana Vide-Escada
- Ophthalmology Department, Hospital Garcia de Orta, Almada, Portugal
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Abstract
A biomarker is a "characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions." Recently, calls for biomarkers for ocular surface diseases have increased, and advancements in imaging technologies have aided in allowing imaging biomarkers to serve as a potential solution for this need. This review focuses on the state of imaging biomarkers for ocular surface diseases, specifically non-invasive tear break-up time (NIBUT), tear meniscus measurement and corneal epithelial thickness with anterior segment optical coherence tomography (OCT), meibomian gland morphology with infrared meibography and in vivo confocal microscopy (IVCM), ocular redness with grading scales, and cellular corneal immune cells and nerve assessment by IVCM. Extensive literature review was performed for analytical and clinical validation that currently exists for potential imaging biomarkers. Our summary suggests that the reported analytical and clinical validation state for potential imaging biomarkers is broad, with some having good to excellent intra- and intergrader agreement to date. Examples of these include NIBUT for dry eye disease, ocular redness grading scales, and detection of corneal immune cells by IVCM for grading and monitoring inflammation. Further examples are nerve assessment by IVCM for monitoring severity of diabetes mellitus and neurotrophic keratitis, and corneal epithelial thickness assessment with anterior segment OCT for the diagnosis of early keratoconus. However, additional analytical validation for these biomarkers is required before clinical application as a biomarker.
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Mohr N, Shajari M, Krause D, Kassumeh S, Siedlecki J, Priglinger SG, Mayer WJ, Luft N. Pellucid marginal degeneration versus keratoconus: distinction with wide-field SD-OCT corneal sublayer pachymetry. Br J Ophthalmol 2020; 105:1638-1644. [PMID: 33055086 DOI: 10.1136/bjophthalmol-2020-316496] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/11/2020] [Accepted: 09/15/2020] [Indexed: 11/03/2022]
Abstract
PURPOSE To evaluate the capability of wide-field spectral-domain optical coherence tomography (SD-OCT) corneal sublayer pachymetry to distinguish between keratoconus and pellucid marginal degeneration (PMD). METHODS This prospective cross-sectional study included 69 eyes (59 with keratoconus and 10 with PMD) of 69 patients. All patients were examined three subsequent times with the RTVue XR system. Pachymetry maps of the total cornea (CT), the epithelium (ET) and the stroma were generated using the onboard software. For analysis of reliability, the coefficients of variation and intraclass correlation coefficients (ICC) were calculated. Receiver operating characteristic analyses were performed to elaborate the most accurate pachymetric parameters for distinguishing between PMD and keratoconus. RESULTS Overall repeatability of (sublayer) pachymetry was comparably good in both keratoconus (ICC ranging between 0.827 and 0.986) and PMD (ICC ranging between 0.753 and 0.998). Measurement reliability in keratoconic eyes was a negative function of Kmax (p<0.05). As compared with keratoconus, PMD exhibited higher CT (526±31 µm vs 503±30 µm; p=0.02) and ET (56±7 µm vs 51±5 µm; p=0.02) in the inferotemporal 2-5 mm sector as well as lower ET in the inferior 7-9 mm sector (52±5 µm vs 57±5 µm; p<0.01). The calculated ratio between CT in the inferotemporal 2-5 mm and in the inferior 7-9 mm sector yielded the highest diagnostic accuracy for distinguishing between PMD and keratoconus with an area under the curve of 0.977 and an optimal cut-off value of 0.90. CONCLUSION Wide-field SD-OCT corneal sublayer pachymetry showed good reliability in PMD and keratoconus and may be useful to differentiate between the two ectatic diseases.
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Affiliation(s)
- Niklas Mohr
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | - Mehdi Shajari
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.,Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | - Daniel Krause
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | - Stefan Kassumeh
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | - Jakob Siedlecki
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.,SMILE Eyes Clinic, Linz, Austria
| | - Siegfried G Priglinger
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.,SMILE Eyes Clinic, Linz, Austria
| | - Wolfgang J Mayer
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | - Nikolaus Luft
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany .,SMILE Eyes Clinic, Linz, Austria
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Masiwa LE, Moodley V. A review of corneal imaging methods for the early diagnosis of pre-clinical Keratoconus. JOURNAL OF OPTOMETRY 2020; 13:269-275. [PMID: 31917136 PMCID: PMC7520528 DOI: 10.1016/j.optom.2019.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/22/2019] [Accepted: 11/09/2019] [Indexed: 05/15/2023]
Abstract
BACKGROUND Keratoconus (KC) is a corneal ectasia characterised by steepening corneal curvature, changes in refractive error and corneal thickness that result in visual impairment. Early signs of KC include displacement of the thinnest part of the cornea from the central position, changes in the corneal epithelial layer cell distribution, variations in the anterior corneal astigmatism/posterior corneal astigmatism relationship and a variation in corneal thickness. It is important that we review the corneal imaging methods for the diagnosis of preclinical KC. METHOD An online literature search was carried out on PubMed. Only publications detailing corneal assessment procedures were considered for this review and any publication on instruments that did not generate KC predictability indices were also excluded from the review. The 308 publications were reviewed. DISCUSSION Corneal assessment techniques, with the ability to characterise both the anterior and posterior corneal surfaces, are invaluable in the diagnosis of pre-clinical KC. Reflection based and elevation based corneal imaging systems should be used in conjunction with other assessments such as higher order aberration measuring systems to improve sensitivity and reliability in the diagnosis of pre-clinical KC. Ultra high resolution ultrasound can detect pre-clinical KC. The ability to asses both the epithelium and endothelium makes anterior surface optical coherence tomography a superior technique for pre-clinical KC diagnosis. There is a positive correlation between central corneal thickness and corneal hysteresis. Corneal biomechanics should be considered in conjunction with other corneal assessments in the diagnosis of pre-clinical KC.
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Affiliation(s)
- Lynett Erita Masiwa
- Department of Ophthalmology, University of Zimbabwe, College of Health Sciences, P. O. Box A178, Avondale, Harare, Zimbabwe.
| | - Vanessa Moodley
- School of Health Sciences, Department of Optometry, University of Kwazulu Natal, Durban, South Africa
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Rattan SA, Anwar DS. Comparison of corneal epithelial thickness profile in dry eye patients, keratoconus suspect, and healthy eyes. Eur J Ophthalmol 2020; 30:1506-1511. [PMID: 32854543 DOI: 10.1177/1120672120952034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To compare the corneal epithelial thickness profile in patients with dry eyes and keratoconus suspect with normal healthy eyes. METHODS The study involved 120 eyes with an age range from 19 to 30 years. Forty eyes had normal corneal topography and no dry eyes. Forty eyes had dry eyes but had normal corneal topography. The last 40 eyes were keratoconus suspect and had no symptoms or signs of dry eyes. RESULTS Central epithelial thickness was not different statistically for all eyes. (p-value: 0.1). The superior epithelial thickness was 53.5 µm ±3.1 in the control group, 53.4 µm ±3.5 in the dry eye group, and 53.6 µm ±2.8 in the keratoconus suspect group. No statistically significant difference was found (p-value = 0.7). The inferior epithelial thickness was 55.7 µm ±3.5 in the control, 57.2 µm ±3.19 in the dry eyes, and 52.2 µm ±3.12 in the KC suspects. There was inferior thickening in the dry eyes and thinning in the KC suspects and this was statistically significant (p-value < 0.01). Minimum epithelial thickness was 52.8 µm ±2.91 in the control and 53.2 µm ±3.51 in the dry eyes and it was located superiorly for both groups. In the KC suspects, the minimum thickness was 52.3 µm ±3.19 and was located inferiorly. CONCLUSION In our study the epithelium appears to be thicker inferiorly in dry eyes and thinner in KC suspects. Displacement of thinnest location on epithelial map may be a helpful early sign of keratoconus. However, follow-up study is necessary to confirm the thinnest location displacement helped in this diagnosis.
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Zhang X, Munir SZ, Sami Karim SA, Munir WM. A review of imaging modalities for detecting early keratoconus. Eye (Lond) 2020; 35:173-187. [PMID: 32678352 DOI: 10.1038/s41433-020-1039-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/28/2020] [Accepted: 06/10/2020] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES Early identification of keratoconus is imperative for preventing iatrogenic corneal ectasia and allowing for early corneal collagen cross-linking treatments to potentially halt progression and decrease transplant burden. However, early diagnosis of keratoconus is currently a diagnostic challenge as there is no uniform screening criteria. We performed a review of the current literature to assess imaging modalities that can be used to help identify subclinical keratoconus. METHODS A Pubmed database search was conducted. We included primary and empirical studies for evaluating different modalities of screening for subclinical keratoconus. RESULTS A combination of multiple imaging tools, including corneal topography, tomography, Scheimpflug imaging, anterior segment optical coherence tomography, and in vivo confocal microscopy will allow for enhanced determination of subclinical keratoconus. In patients who are diagnostically borderline using a single screening criteria, use of additional imaging techniques can assist in diagnosis. Modalities that show promise but need further research include polarization-sensitive optical coherence tomography, Brillouin microscopy, and atomic force microscopy. CONCLUSIONS Recognition of early keratoconus can reduce risk of post-refractive ectasia and reduce transplantation burden. Though there are no current uniform screening criterion, multiple imaging modalities have shown promise in assisting with the early detection of keratoconus.
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Affiliation(s)
- Xuemin Zhang
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Saleha Z Munir
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Syed A Sami Karim
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Wuqaas M Munir
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
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Atalay E, Yu DJ, Nongpiur ME. When to use anterior segment optical coherence tomography. EXPERT REVIEW OF OPHTHALMOLOGY 2020. [DOI: 10.1080/17469899.2020.1767596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Eray Atalay
- Department of Ophthalmology, Eskisehir Osmangazi University Faculty of Medicine, Turkey
| | - Daryle Jason Yu
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Monisha Esther Nongpiur
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Duke-NUS Medical School, Singapore, Singapore
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Utility of regional epithelial thickness measurements in corneal evaluations. Surv Ophthalmol 2020; 65:187-204. [DOI: 10.1016/j.survophthal.2019.09.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 09/10/2019] [Accepted: 09/16/2019] [Indexed: 11/19/2022]
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Schiano-Lomoriello D, Bono V, Abicca I, Savini G. Repeatability of anterior segment measurements by optical coherence tomography combined with Placido disk corneal topography in eyes with keratoconus. Sci Rep 2020; 10:1124. [PMID: 31980662 PMCID: PMC6981210 DOI: 10.1038/s41598-020-57926-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 01/06/2020] [Indexed: 02/07/2023] Open
Abstract
Corneal tomography is an important tool to identify and follow up eyes with keratoconus. Our study evaluate the repeatability of the automatic measurements provided in keratoconic eyes by a new anterior-segment optical coherence tomographer (AS-OCT) combined with Placido-disk topography (MS-39, CSO) and assess their agreement with the corresponding measurements taken with a rotating Scheimpflug camera combined with Placido-disk topography (Sirius, CSO). Mean simulated keratometry, posterior and total corneal power, total corneal astigmatism, corneal asphericity, thinnest corneal thickness, epithelial thickness, corneal diameter, and aqueous depth were evaluated. Repeatability was assessed using test–retest variability, the coefficient of variation, and the intraclass correlation coefficient; agreement was assessed by the 95% limits of agreement. Good repeatability was achieved for most parameters. Moderate repeatability was found for total corneal astigmatism measurements. The repeatability of mean simulated keratometry and total corneal power measurements worsened with more severe stages of keratoconus with a statistically significant relationship between the individual coefficient of variation and corneal power values. Agreement with the Scheimpflug camera was moderate for aqueous depth and thinnest corneal thickness and poor for most other measured parameters. The good repeatability of automatic measurements suggests the new AS-OCT device to be a viable option in clinical practice of eyes with keratoconus.
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Pircher N, Beer F, Holzer S, Gschließer A, Donner R, Pircher M, Hitzenberger CK, Schmidinger G, Lammer J. Large Field of View Corneal Epithelium and Bowman's Layer Thickness Maps in Keratoconic and Healthy Eyes. Am J Ophthalmol 2020; 209:168-177. [PMID: 31170392 DOI: 10.1016/j.ajo.2019.05.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/19/2019] [Accepted: 05/15/2019] [Indexed: 11/29/2022]
Abstract
PURPOSE To assess differences between epithelium thickness (ET) and Bowman's layer thickness (BLT) maps in keratoconic eyes and healthy eyes. DESIGN Cross-sectional study. METHODS Setting: institutional. STUDY POPULATION 47 patients (1 eye) with keratoconus (KC) and 20 healthy subjects (1 eye). OBSERVATION PROCEDURE epithelium and Bowman's layer measurements were performed by using custom-designed polarization-sensitive optical coherence tomography (PS-OCT) with a conical scanning optics design. En face corneal ET and BLT maps with a diameter of 11 mm were computed. Main outcome measurements were mean ET and BLT of 25 sectors; the thinnest (minET, minBLT) and thickest sectors (maxET, maxBLT) were assessed. Ratios between thinnest/thickest sectors (R1) and between mean ET and BLT of the inferior temporal quadrant/superior nasal quadrant (R2) were calculated (R1ET, R1BLT; R2ET, R2BLT). Receiver operator characteristic (ROC) curve analysis was used to assess the diagnostic power of statistically different parameters. RESULTS In healthy eyes, smooth ET maps were observed. KC eyes showed a "doughnut pattern." The BLT maps of healthy eyes had a smooth appearance, but highly irregular "moth"-like damage pattern could be observed in keratoconic eyes. Highest area under the curve values were found for the thinnest sector of the BLT map, the R1ET, and the thinnest sector of the ET map. CONCLUSIONS PS-OCT imaging enables the visualization of significant differences of the corneal epithelium and the Bowman's layer in en face maps covering almost the entire cornea. ET and BLT profiles could clearly show their diagnostic importance for the distinguishing of keratoconic eyes and healthy eyes.
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Affiliation(s)
- Niklas Pircher
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Florian Beer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Stephan Holzer
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Andreas Gschließer
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Ruth Donner
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Michael Pircher
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Christoph K Hitzenberger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Gerald Schmidinger
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Jan Lammer
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria.
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Tong J, Phu J, Kalloniatis M, Zangerl B. Modeling Changes in Corneal Parameters With Age: Implications for Corneal Disease Detection. Am J Ophthalmol 2020; 209:117-131. [PMID: 31469999 DOI: 10.1016/j.ajo.2019.08.014] [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: 02/24/2019] [Revised: 08/19/2019] [Accepted: 08/19/2019] [Indexed: 11/19/2022]
Abstract
PURPOSE To apply computational methods to model normal age-related changes in corneal parameters and to establish their association with demographic factors, thereby providing a framework for improved detection of subclinical corneal ectasia (SCE). DESIGN Cross-sectional study. METHODS One hundred seventeen healthy participants were enrolled from Centre for Eye Health (Sydney, Australia). Corneal thickness (CT), front surface sagittal curvature (FSSC), and back surface sagittal curvature (BSSC) measurements were extracted from 57 corneal locations from 1 eye per participant using the Pentacam HR. Cluster analyses were performed to identify locations demonstrating similar variations with age. Age-related changes were modeled using polynomial regression with sliding window methods, and model accuracy was verified with Bland-Altman comparisons. Pearson correlations were applied to examine the impacts of demographic factors. RESULTS Concentric cluster patterns were observed for CT and FSSC but not for BSSC. Sliding window analyses were best fit with quartic and cubic regression models for CT and FSSC/BSSC, respectively. CT and FSSC sliding window models had narrower 95% limits of agreement compared with decade-based models (0.015 mm vs 0.017 mm and 0.14 mm vs 0.27 mm, respectively), but were wider for BSSC than decade-based models (0.73 mm vs 0.54 mm). Significant correlations were observed between CT and astigmatism (P = .02-.049) and FSSC and BSSC and gender (P = <.001-.049). CONCLUSIONS The developed models robustly described aging variations in CT and FSSC; however, other mechanisms appear to contribute to variations in BSSC. These findings and the identified correlations provide a framework that can be applied to future model development and establishment of normal databases to facilitate SCE detection.
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Affiliation(s)
- Janelle Tong
- Centre for Eye Health and the School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Jack Phu
- Centre for Eye Health and the School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Michael Kalloniatis
- Centre for Eye Health and the School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Barbara Zangerl
- Centre for Eye Health and the School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.
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Ziaei M, Meyer J, Gokul A, Vellara H, McGhee CNJ. Direct measurement of anterior corneal curvature changes attributable to epithelial removal in keratoconus. J Cataract Refract Surg 2019; 44:71-77. [PMID: 29502621 DOI: 10.1016/j.jcrs.2017.10.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 02/08/2023]
Abstract
PURPOSE To compare the tomography of the corneal epithelium and Bowman layer in eyes with moderate to severe keratoconus before and after epithelial debridement. SETTING University hospital tertiary referral center. DESIGN Prospective case series. METHODS Dual-channel Scheimpflug combined with Placido-disk tomography was used to measure the corneal variables in eyes with keratoconus having corneal crosslinking immediately before and after epithelial debridement. The differences in pachymetry, axial keratometry, astigmatism magnitude, asphericity, total corneal power, and spherical aberrations were computed. RESULTS The study comprised 30 eyes of 30 patients. After epithelial removal, the central (0.0 to 4.0 mm) and midperipheral (4.0 to 7.0 mm) corneal zones were significantly thinner mean (21 μm ± 14 [SD] and 35 ± 44 μm, respectively). The mean anterior axial flat keratometry (K) (+1.71 diopters [D]), steep K (+2.14 D), maximum K (+2.13 D), corneal astigmatism (+1.11 D), asphericity (-0.31), and total corneal power changes (+2.03 D) were significantly different after epithelial debridement. There were no significant changes in posterior corneal flat K or steep K, posterior corneal astigmatism, or posterior asphericity. There were no significant differences in the mean astigmatic axis (anterior or posterior corneal surface) or spherical aberration after epithelial debridement. CONCLUSIONS In eyes with moderate to severe keratoconus, the tomography of Bowman layer was significantly steeper than that of the epithelium; thus, epithelial debridement increased the magnitude of anterior corneal keratometry, astigmatism, and prolateness. These data suggest that the corneal epithelium smooths the underlying Bowman layer irregularity in keratoconus.
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Affiliation(s)
- Mohammed Ziaei
- From the Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
| | - Jay Meyer
- From the Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Akilesh Gokul
- From the Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Hans Vellara
- From the Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Charles N J McGhee
- From the Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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Corneal epithelial thickness profile in dry-eye disease. Eye (Lond) 2019; 34:915-922. [PMID: 31576026 DOI: 10.1038/s41433-019-0592-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 03/13/2019] [Accepted: 07/04/2019] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND/OBJECTIVES To characterize and evaluate the use of corneal epithelial profile maps generated by an ultrahigh-resolution optical coherence tomography (UHR-OCT) in the diagnosis and management of dry-eye disease (DED). SUBJECTS/METHODS This prospective, interventional case-control study included 115 eyes of 71 subjects (52 DED and 19 controls) imaged using an UHR-OCT. Average, maximum, and minimum, range of corneal epithelial thicknesses were extracted from epithelial profile maps. Surface regularity was quantified using the range and variance of the epithelial thickness measured along a horizontal UHR-OCT scan. The variance of thickness measurements along a scan was named epithelial irregularity factor (EIF). Symptoms of 31 DED patients (55 eyes) were quantified by questionnaire and correlated to epithelial profile findings, fluorescein staining, tear breakup time, and Schirmer's test. Twenty-one DED eyes were administered autologous serum drops and follow-up UHR-OCT images were captured. RESULTS DED patients had a highly irregular corneal epithelial surface compared with controls. Epithelial thickness profile variance (EIF) and range were significantly higher in DED as compared with controls (5.79 vs. 0.77, p < 0.001 and 7.6 vs. 4.6 μm, p < 0.001). Both parameters were highly significantly correlated with questionnaire scores (EIF: r = 0.778; p < 0.001, range: r = 0.737; p < 0.001). Follow-up showed a statistically significant reduction in epithelial thickness profile variance and range of treated patients ( p < 0.001). CONCLUSIONS DED patients have irregular epithelial surface that can be quantified using UHR-OCT generated CEP maps. Epithelial thickness profile range and EIF correlate accurately with patients' symptoms and could be used to follow-up patients and response to treatment.
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Analysis of Compensatory Corneal Epithelial Thickness Changes in Keratoconus Using Corneal Tomography. Cornea 2019; 39:298-302. [PMID: 31567631 DOI: 10.1097/ico.0000000000002156] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine patterns of epithelial remodeling in keratoconus and to assess changes in these patterns as the disease progresses. METHODS This is a prospective case series. Patients with keratoconus undergoing corneal collagen crosslinking underwent Scheimpflug imaging before and after epithelial debridement. Analysis was performed to determine maps of epithelial thickness and change in keratometry. Maps were analyzed for patterns, and map SD was quantified. Measures were compared across the patients as grouped by the severity of disease. RESULTS The study comprised 38 eyes from 30 patients. Patients were stratified using the Amsler-Krumeich classification of keratoconus severity, with 17, 14, and 7 patients in the stage I, stage II, and stage III groups, respectively. A pattern of central epithelial thinning (to approximately 20 μm) with an annulus of epithelial thickening (to approximately 30-40 μm) was demonstrated. Changes were more pronounced in the later stages of the disease, with the average central thickness decreasing from 23 μm in stage I to 18 μm in stage III. Central corneal steepening of 1.5 to 1.9 diopters and peripheral flattening of 1.4 to 2.0 diopters after epithelial debridement were demonstrated. Analysis of map SD revealed a significant difference between stage III patients and patients at earlier stages of disease. CONCLUSIONS The "doughnut pattern" of epithelial remodeling in keratoconus is supported by Scheimpflug imaging. This pattern is demonstrated to partially compensate for central corneal steepening seen in keratoconus.
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Corneal Biomechanics in Unilateral Keratoconus and Fellow Eyes with a Scheimpflug-based Tonometer. Optom Vis Sci 2019; 95:608-615. [PMID: 29957740 DOI: 10.1097/opx.0000000000001241] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
SIGNIFICANCE Before the appearance of evident keratoconus, corneal biomechanical changes may be detectable. Here, these properties are analyzed to detect any difference that could help in the early recognition of keratoconus to allow patients to benefit from early treatments and to avoid refractive procedures in these corneas. PURPOSE The purpose of this study was to compare corneal biomechanical characteristics as determined by Corvis Scheimpflug Technology tonometry between normal eyes and asymmetric keratoconic eyes. METHODS Retrospective data from normal eyes (n = 100), keratoconic eyes (n = 18), and their topographically normal fellow eyes (n = 18) were analyzed. Differences in the variables among the groups were determined. For the parameters that showed significant differences, the receiver operating characteristic curve and the area under the curve (AUC) were used to assess the diagnostic accuracy of each variable. The optimal cutoff points were determined when comparing normal and fellow eyes. Also, a new linear combination of variables was performed to obtain better discriminative values. RESULTS The following variables differed significantly between normal and fellow eyes: length of the flattened cornea in the second applanation, peak distance, curvature radius at highest concavity, and central corneal thickness. When each variable was independently considered, AUCs, sensitivity, and specificity were insufficiently high for good discrimination between the two groups. However, using a linear combination of variables, an optimal cutoff point (0.157) was obtained with an AUC of 0.78, sensitivity of 0.84, and specificity of 0.69. CONCLUSIONS A best predictive linear combination of corneal biomechanical variables was tested including diameter of the flattened cornea in the second applanation and central corneal thickness. This combination was considered as the best in terms of its prediction capacity, simplicity and clinical application. This formula may be useful in clinical practice to discriminate between normal eyes and incipient keratoconus.
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