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Gilevska F, Biscevic A, Bohac M, Patel S. Could Automated Objective Measurements Acquired at the Preoperative Stage Estimate the Corrected Distance Visual Acuity after Corneal Cross-Linking in Keratoconus? Ophthalmol Ther 2024; 13:2599-2614. [PMID: 39110318 PMCID: PMC11408454 DOI: 10.1007/s40123-024-00993-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/27/2024] [Indexed: 09/19/2024] Open
Abstract
INTRODUCTION Objective markers describing corneal optical density (COD), thinnest corneal thickness (TCT), and anterior (ARC) and posterior (PRC) surface radii over the 3 mm thinnest region of the cornea were investigated to provide a model for estimating corrected distance visual acuity (CDVA) after corneal cross-linking (CXL) in keratoconus. METHODS CDVA, COD, TCT, ARC, and PRC were monitored (using Pentacam™) over 1 year in patients with (1) keratoconus treated with routine CXL (2) relatively stable untreated keratoconus, and (3) age/gender-matched controls. RESULTS In group 1 (n = 77), the median logMAR CDVA (mode, interquartile range) improved significantly (p < 0.01) from 0.26 (0.22, 0.12-0.65) to 0.07 (0.00, 0.02-0.21). The mean (± standard deviation, 95% confidence interval) COD (in 0-100 grey scale units) in the 0-2 mm central anterior corneal region (0-2 ant), TCT (µm), ARC (mm), and PRC (mm) changed significantly (p < 0.01), from 21.2 (± 3.70, 20.4-22.0), 454 (± 40.0, 446-462), 6.49 (± 0.71, 6.33-6.65), and 4.81 (± 0.65, 4.66-4.96) to 31.5 (± 9.19, 29.5-33.6), 423 (± 49.3, 412-434), 6.78 (± 0.80, 6.60-6.98), and 4.74 (± 0.64, 4.59-4.88), respectively, but remained stable in groups 2 (n = 23) and 3 (n = 24). Significant relationships (p < 0.01) were uncovered between postop CDVA and preop values of COD, TCT, ARC, and PRC. Multilinear regression revealed significant correlations between CDVA at 1 year and preop COD, TCT, ARC, and PRC (r2 = 0.533, r20-2ant = 0.126, r2TCT = 0.321, r2ARC = 0.506, r2PRC = 0.467). Including preop CDVA further enhanced this correlation (r2 = 0.637, r2LogMAR CDVApreop = 0.566). CONCLUSION CXL improved CDVA, increased COD and ARC, and reduced TCT and PRC. The chance of correctly estimating the CDVA at 1 year after CXL using preoperative markers of COD, TCT, ARC, and PRC is 53%, improving to 64% with the inclusion of preoperative CDVA. Objective measurements taken at the preoperative screening stage may be useful to estimate the likely postoperative CDVA when preoperative CDVA measures are unreliable or unobtainable. TRIAL REGISTRATION ClinicalTrials.gov identifier, NCT06522789.
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Affiliation(s)
- Fanka Gilevska
- Eye Clinic Sistina Oftalmologija, Skupi 5A, Skopje, Republic of North Macedonia.
| | - Alma Biscevic
- Department of Cataract and Refractive Surgery, University Eye Hospital Svjetlost, 10000, Zagreb, Croatia
| | - Maja Bohac
- Department of Cataract and Refractive Surgery, University Eye Hospital Svjetlost, 10000, Zagreb, Croatia
| | - Sudi Patel
- Department of Cataract and Refractive Surgery, University Eye Hospital Svjetlost, 10000, Zagreb, Croatia
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Yang Q, Ju G, He Y. Corneal densitometry: A new evaluation indicator for corneal diseases. Surv Ophthalmol 2024:S0039-6257(24)00122-X. [PMID: 39326741 DOI: 10.1016/j.survophthal.2024.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 09/19/2024] [Accepted: 09/23/2024] [Indexed: 09/28/2024]
Abstract
Corneal densitometry (CD) uses the biological properties of the cornea to visualize the morphology of the cornea and determine the degree of corneal transparency. At present, it is an emerging metric that has shown promise in various clinical diagnosis and evaluation of eye diseases and surgeries. We introduce the different methodologies used to measure CD. Furthermore, we systematically categorize the diagnostic value of CD into high, medium, and low levels based on its clinical significance. By analyzing a wide range of conditions, including keratoconus, postrefractive surgery changes, and other corneal pathologies, we assess the utility of CD in each context. We also discuss the potential implications of these classifications for disease monitoring and prognosis evaluation. Our review underscores the importance of integrating CD assessments into routine clinical practice to enhance the accuracy and effectiveness of diagnostic processes for corneal disorders.
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Affiliation(s)
- Qing Yang
- Department of Ophthalmology, the Second Hospital of Jilin University, Changchun, Jilin 130041, China; The Second Clinical Medical College of Jilin University, Changchun, Jilin 130012, China
| | - Gen Ju
- Department of Ophthalmology, Baoji People's Hospital, Baoji, Shaanxi 721000, China
| | - Yuxi He
- Department of Ophthalmology, the Second Hospital of Jilin University, Changchun, Jilin 130041, China.
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Jiang Y, Jiang H, Zhang J, Chen T, Li Y, Zhou Y, Chen Y, Li F. The development of a machine learning model to train junior ophthalmologists in diagnosing the pre-clinical keratoconus. Front Med (Lausanne) 2024; 11:1458356. [PMID: 39359918 PMCID: PMC11445185 DOI: 10.3389/fmed.2024.1458356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Accepted: 09/02/2024] [Indexed: 10/04/2024] Open
Abstract
Purpose This study aims to evaluate the diagnostic performance of a machine learning model (ML model) to train junior ophthalmologists in detecting preclinical keratoconus (PKC). Methods A total of 1,334 corneal topography images (The Pentacam HR system) from 413 keratoconus eyes, 32 PKC eyes and 222 normal eyes were collected. Five junior ophthalmologists were trained and annotated the images with or without the suggestions proposed by the ML model. The diagnostic performance of PKC was evaluated among three groups: junior ophthalmologist group (control group), ML model group and ML model-training junior ophthalmologist group (test group). Results The accuracy of the ML model between the eyes of patients with KC and NEs in all three clinics (99% accuracy, area under the receiver operating characteristic (ROC) curve AUC of 1.00, 99% sensitivity, 99% specificity) was higher than that for Belin-Ambrósio enhanced ectasia display total deviation (BAD-D) (86% accuracy, AUC of 0.97, 97% sensitivity, 69% specificity). The accuracy of the ML model between eyes with PKC and NEs in all three clinics (98% accuracy, AUC of 0.96, 98% sensitivity, 98% specificity) was higher than that of BAD-D (69% accuracy, AUC of 0.73, 67% sensitivity, 69% specificity). The diagnostic accuracy of PKC was 47.5% (95%CI, 0.5-71.6%), 100% (95%CI, 100-100%) and 94.4% (95%CI, 14.7-94.7%) in the control group, ML model group and test group. With the assistance of the proposed ML model, the diagnostic accuracy of junior ophthalmologists improved with statistical significance (p < 0.05). According to the questionnaire of all the junior ophthalmologists, the average score was 4 (total 5) regarding to the comprehensiveness that the AI model has been in their keratoconus diagnosis learning; the average score was 4.4 (total 5) regarding to the convenience that the AI model has been in their keratoconus diagnosis learning. Conclusion The proposed ML model provided a novel approach for the detection of PKC with high diagnostic accuracy and assisted to improve the performance of junior ophthalmologists, resulting especially in reducing the risk of missed diagnoses.
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Affiliation(s)
- Yang Jiang
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
- Key Laboratory of Ocular Fundus Diseases, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Hanyu Jiang
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
- Key Laboratory of Ocular Fundus Diseases, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- Eight-Year Medical Doctor Program, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Jing Zhang
- Department of Ophthalmology, Beijing Ming Vision Clinic, Beijing, China
| | - Tao Chen
- Department of Ophthalmology, Beijing Fenglian Jiayue Lege Clinic, Beijing, China
| | - Ying Li
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
- Key Laboratory of Ocular Fundus Diseases, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yuehua Zhou
- Department of Ophthalmology, Beijing Ming Vision Clinic, Beijing, China
| | - Youxin Chen
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
- Key Laboratory of Ocular Fundus Diseases, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Fusheng Li
- Department of Ophthalmology, Beijing Ming Vision Clinic, Beijing, China
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Hammoud B, Dupps WJ, Scarcelli G, Randleman JB. Misclassification of Eyes With Progressive Keratoconus Using the KISA% Index. J Refract Surg 2024; 40:e614-e624. [PMID: 39254254 DOI: 10.3928/1081597x-20240726-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
PURPOSE To determine the misclassification rate of the keratoconus percentage (KISA%) index efficacy in eyes with progressive keratoconus. METHODS This was a retrospective case-control study of consecutive patients with confirmed progressive keratoconus and a contemporaneous normal control group with 1.00 diopters or greater regular astigmatism. Scheimpflug imaging (Pentacam HR) was obtained for all patients. KISA% index and inferior-superior (IS) values were obtained from the Pentacam topometric/keratoconus staging map. Receiver operating characteristic curves were generated to determine the area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity values. RESULTS There were 160 eyes from 160 patients evaluated, including 80 eyes from 80 patients with progressive keratoconus and 80 eyes from 80 control patients. There were 20 eyes (25%) with progressive keratoconus misclassified by the KISA% index, with 16 eyes (20%) of the progressive keratoconus cohort classified as normal (ie, KISA% < 60). There were 4 eyes (5%) with progressive keratoconus that would classify as having "normal topography" using the published criteria for very asymmetric ectasia with normal topography of KISA% less than 60 and IS value less than 1.45. All controls had a KISA% index value of less than 15. The optimal cut-off value to distinguish cohorts was 15.31 (AUROC = 0.972, 93.75% sensitivity). KISA% index values of 60 and 100 achieved low sensitivity (80% and 73.75%, respectively). CONCLUSIONS The KISA% index misclassified a significant proportion of eyes with progressive keratoconus as normal. Although highly specific for clinical keratoconus, the KISA% index lacks sensitivity, does not effectively discriminate between normal and abnormal topography, and thus should not be used in large data analysis or artificial intelligence-based modeling. [J Refract Surg. 2024;40(9):e614-e624.].
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Hashemi A, Nabovati P, Hashemi H, Mortazavi AG, Khabazkhoob M. Corneal densitometry and associated factors in an elderly population. Clin Exp Optom 2024; 107:522-529. [PMID: 37674266 DOI: 10.1080/08164622.2023.2242864] [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: 04/15/2023] [Accepted: 07/26/2023] [Indexed: 09/08/2023] Open
Abstract
CLINICAL RELEVANCE Knowing normative corneal optical density (COD) values is important for identifying pathologic corneal changes. BACKGROUND The aim of this work is to determine the distribution and associated factors of COD in the elderly population. METHODS This report is a part of a cross-sectional population-based study conducted on the elderly population (≥60 years) of Tehran, Iran from Jan 2019 to Jan 2020. Using a multi-stage stratified random cluster sampling method, a total of 160 clusters were randomly selected from 22 districts of Tehran city. Study participants underwent a complete ocular examination including measurement of visual acuity, refraction, and slit-lamp biomicroscopy. Corneal densitometry was evaluated using the Pentacam HR. Generalized estimating equation (GEE) models were used to investigate associations of COD with study variables. RESULTS A total of 3633 eyes from 2068 individuals were analysed. Of these, 1256 (60.7%) were female, and the mean age of the individuals was 66.42 ± 5.28 (60 to 95) years. The mean entire COD was 21.96 ± 4.45 greyscale unit (GSU) (95% CI: 21.57-22.34). There was a statistically significant difference in the mean COD between the anterior, central, and posterior layers (p < 0.001); the highest and lowest average COD was related to the anterior and posterior corneal layers, respectively. The lowest and highest mean COD were observed in the 0-2 mm [17.21GSU (95% CI:16.87-17.55)], and 10-12 mm annular zones [31.4 GSU (95% CI: 30.89-31.91)], respectively (p < 0.001). According to the multiple GEE model, the COD had a statistically significant direct relationship with age, central corneal thickness, and mean keratometry, while it was significantly inversely associated with female sex, anterior chamber depth, white-to-white distance, and corneal volume. CONCLUSION These normal values of COD in the present study could be used as reference data in older adults. The associated factors of COD should be taken into account to avoid misinterpretation of physiologic changes as pathologic processes.
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Affiliation(s)
- Alireza Hashemi
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Payam Nabovati
- Rehabilitation Research Center, Department of Optometry, Iran University of Medical Sciences, Tehran, Iran
| | - Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Abol Ghasem Mortazavi
- Department of Neurosurgery, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Yang M, Tian H, Xue C, Li J. Diagnostic value of corneal optical densitometry in keratoconus. Int Ophthalmol 2024; 44:294. [PMID: 38943020 DOI: 10.1007/s10792-024-03212-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 06/15/2024] [Indexed: 06/30/2024]
Abstract
PURPOSE To investigate the clinical significance of the correlation between optical densitometry and both biomechanical and morphological parameters in keratoconus (KC) and to verify the diagnostic value of optical densitometry in KC. METHOD This cross-sectional study included 436 eyes of 295 patients with KC. Corneal optical densitometry, morphological parameters and biomechanical parameters were measured. Spearman's correlation analysis was employed to investigate the association between optical densitometry and both biomechanical and morphological parameters. RESULT Optical densitometry of the anterior (0-2 mm and 2-6 mm), central (0-2 mm), posterior (2-6 mm) and total (2-6 mm) layers correlated positively with SPA1, while the posterior layer (0-2 mm) correlated negatively. Optical densitometry of the anterior layers 2-6 mm, 6-10 mm, and the central layer 6-10 mm negatively affected AL1, while the posterior layer 0-2 mm positively affected it. Optical densitometry of the anterior, central, and posterior layers 0-2 mm and 2-6 mm positively influenced the morphological parameters K1F, K2F, KmF and the absolute values of K1B, K2B, KmB. Optical densitometry of the center (0-2 mm) and posterior (2-6 mm) layers negatively influenced TCT. Optical densitometry of the anterior (0-2 mm and 2-6 mm), center (0-2 mm), posterior (2-6 mm) and total (2-6 mm) layers correlated positively with ACE and PCE, whereas the posterior layer (0-2 mm) correlated negatively. CONCLUSION Optical densitometry was correlated with biomechanical and morphological parameters in keratoconus, suggesting its potential as a diagnostic indicator for assessing keratoconus progression and treatment efficacy.
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Affiliation(s)
- Min Yang
- School of Medicine, Nankai University, Tianjin, China
| | - He Tian
- School of Medicine, Nankai University, Tianjin, China
| | - Chao Xue
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin, China.
- Nankai University Afliated Eye Hospital, Nankai University, Tianjin, China.
| | - Jing Li
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Afliated People's Hospital of Northwest University, Xi'an, 710004, China.
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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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Yang D, Chen Z, Zhao W, Zhao J, Zhou X, Wang J. Characterization the corneal transparency profile in SMILE-treated myopic patients with densitometry: A 7-year cohort study. Indian J Ophthalmol 2024; 72:S429-S434. [PMID: 38317330 PMCID: PMC467034 DOI: 10.4103/ijo.ijo_1787_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/18/2023] [Accepted: 11/03/2023] [Indexed: 02/07/2024] Open
Abstract
PURPOSE To investigate 7-year changes in corneal densitometry (CD) and its influencing factors following small incision lenticule extraction (SMILE) for moderate to high myopia. METHODS A total of 32 patients (52 eyes) with a mean spherical equivalent (SE) refraction of -6.30 ± 1.30 D who underwent SMILE were recruited for this prospective study. Pre- and postoperative CD and corneal aberrations were measured by an oculus Pentacam system, and patients were followed up to 7 years. The CD evolution over time and its influencing factors were explored. RESULTS No complications were observed after SMILE. There was a significant time effect on postoperative CD ( P < 0.05). The CD values at the 0-to-2 and 2-to-6 mm of the anterior layer increased at the first day ( P < 0.05) and declined to baselines at 1 year postoperatively; after that, CD values at any zone and any corneal layer presented a decreasing trend over time (all P < 0.05). Multivariate analysis showed that postoperative CD was positively correlated with age and optical zone (OZ), whereas negatively correlated with SE, corrected distance visual acuity (CDVA), and corneal aberrations (higher-order aberrations, Coma0 and Coma90) (all P < 0.05). Generalized estimating equation revealed that age, SE, CDVA, OZ, and Coma0 were the main factors influencing postoperative CD values (all P < 0.05). CONCLUSION CD manifested a long-term decreasing trend in moderate to high myopia treated with SMILE. Its main influencing factors are age, SE, CDVA, OZ, and Coma0.
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Affiliation(s)
- Dongmei Yang
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Second People's Hospital of Yunnan Province, Affiliated Hospital of Yunnan University, Kunming, China
| | - Zhuoyi Chen
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Wuxiao Zhao
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Center for Optometry and Visual Science, The People’s Hospital of Guangxi Zhuang Autonomous Region, Guangxi Academy of Medical Sciences, Nanning, China
| | - Jing Zhao
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Jifang Wang
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Department of Nursing, Eye and ENT Hospital, Fudan University, Shanghai, China
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Yilmaz YC, Ipek SC, Gobeka HH. Corneal topometric indices and proclivity toward corneal ectasia in vernal keratoconjunctivitis. J Fr Ophtalmol 2024; 47:103792. [PMID: 37087321 DOI: 10.1016/j.jfo.2023.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 12/27/2022] [Accepted: 01/06/2023] [Indexed: 04/24/2023]
Abstract
PURPOSE To investigate changes in topometric corneal indices and proclivity toward corneal ectasia, as well as keratometric indices and anterior chamber dimensions in palpebral vernal keratoconjunctivitis (VKC). METHODS This study included 80 patients with clinically established symptoms of grade 0 or grade 1 palpebral VKC (group 1) and 66 healthy participants (group 2). After a comprehensive ophthalmic examination including best-corrected visual acuity, intraocular pressure measurements and slit-lamp biomicroscopy, pachymetric indices and anterior chamber dimensions were measured using the Pentacam HR rotating Scheimpflug device. Topometric indices, which are particularly useful for determining proclivity toward corneal ectasia, were extracted from a topometric map. RESULTS In groups 1 and 2, the mean ages were 13.11±5.22 and 16.45±5.09 years, respectively. The mean age at disease onset in group 1 was 10.09±5.03 years, and the mean disease duration was 36.23±8.43 months. Group 1 had significantly higher mean topometric indices than group 2, particularly the index of surface variance (P=0.001), index of vertical asymmetry (P=0.007), center keratoconus index (P=0.050), and Belin/Ambrosio enhanced ectasia total deviation value (P=0.032). Mean posterior corneal astigmatism differed significantly between groups 1 and 2 (P=0.003). CONCLUSIONS Significantly higher mean topometric indices in VKC indicate a proclivity for corneal ectasia, which could be attributed to general changes in the corneal ultrastructure caused by persistent itching-induced eye rubbing.
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Affiliation(s)
- Y C Yilmaz
- Agri İbrahim Cecen University Faculty of Medicine, Department of Ophthalmology, Agri, Turkey; Başakşehir Çam Sakura State Hospital, Department of Ophthalmology, Istanbul, Turkey.
| | - S C Ipek
- Agri İbrahim Cecen University Faculty of Medicine, Department of Ophthalmology, Agri, Turkey; Bodrum Gözakademi Private Eye Hospital, Bodrum/Mugla, Turkey.
| | - H H Gobeka
- Agri İbrahim Cecen University Faculty of Medicine, Department of Ophthalmology, Agri, Turkey; Afyonkarahisar Health Sciences University, Faculty of Medicine, Department of Ophthalmology, Afyonkarahisar, Turkey.
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Consejo A, Roman DM, Roll V, Remon L. Relationship between corneal tissue and shape in short-term soft contact lens wear. Ophthalmic Physiol Opt 2023; 43:1372-1378. [PMID: 37551625 DOI: 10.1111/opo.13211] [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: 06/05/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/09/2023]
Abstract
PURPOSE To investigate which morphometric and ocular surface tissue parameters are affected by short-term soft contact lens (CL) wear and to assess whether they carry related or independent information. METHODS Twenty-two healthy participants wore silicone hydrogel (SiHy; MyDay, CooperVision) soft CLs for 8 h in their left eye. Corneal tomography and corneoscleral topography were captured before and immediately after CL wear. Central corneal thickness (CCT), corneoscleral parameters (limbus position and corneoscleral junction [CSJ] angle) and corneal tissue parameters (corneal transparency and homogeneity) were evaluated. RESULTS Corneoscleral parameters (limbus position and CSJ angle) were independent of corneal tissue parameters (transparency and homogeneity) at baseline and after CL wear. CCT was independent of all the other parameters examined at baseline, but baseline values of corneal tissue parameters were moderately correlated with CCT change (transparency: r = -0.51; p = 0.007), homogeneity: r = -0.46; p = 0.02). CONCLUSIONS A complete characterisation of ocular surface changes following CL wear should consider corneoscleral topography and corneal densitometry simultaneously, since they carry complementary information.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
- Aragon Institute for Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - Denisa M Roman
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - Vanesa Roll
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - Laura Remon
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
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Wang H, Zhang X, Gao X, Li W. Characteristics of brittle cornea syndrome by multimodal imaging modalities: a case report. BMC Ophthalmol 2023; 23:378. [PMID: 37710225 PMCID: PMC10503189 DOI: 10.1186/s12886-023-03123-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 09/01/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND A report of a Brittle cornea syndrome (BCS) case with bluish scleral discoloration, keratoglobus, and myopia based on multimodal imaging modalities including in vivo confocal microscopy (IVCM), high-definition optical coherence tomography (HD-OCT) and scheimpflug corneal densitometry analysis. CASE PRESENTATION A 36-year-old Chinese female patient presented with significant bluish discoloration of the sclera in both eyes, extreme corneal thinning with increased corneal curvature, increased central corneal densitometry, and nystagmus. She also had scoliosis, severe osteoporosis, and thyroid disease. CONCLUSIONS Timely diagnosis, early detection, and detailed follow-up are essential for BCS. There has been no report of a BCS evaluation performed by IVCM and corneal densitometry methods thus far in the literature. Furthermore, multimodal imaging can offer a more comprehensive view of BCS and contribute to a deeper understanding of the disease. Interestingly, this is a rare case of BCS in an adult with good vision, an intact cornea, and nystagmus.
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Affiliation(s)
- Huixian Wang
- Xinjiang 474 Hospital (the former 474 Hospital of the People's Liberation Army), Beijing Road 754, Urimqi, 830000, Xinjiang Autonomous Region, China
| | - Xu Zhang
- Xinjiang 474 Hospital (the former 474 Hospital of the People's Liberation Army), Beijing Road 754, Urimqi, 830000, Xinjiang Autonomous Region, China
| | - Xiaowei Gao
- Xinjiang 474 Hospital (the former 474 Hospital of the People's Liberation Army), Beijing Road 754, Urimqi, 830000, Xinjiang Autonomous Region, China
| | - Wenjing Li
- Xinjiang 474 Hospital (the former 474 Hospital of the People's Liberation Army), Beijing Road 754, Urimqi, 830000, Xinjiang Autonomous Region, China.
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12
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Miażdżyk M, Consejo A, Iskander DR. OCT based corneal densitometry: the confounding effect of epithelial speckle. BIOMEDICAL OPTICS EXPRESS 2023; 14:3871-3880. [PMID: 37799674 PMCID: PMC10549732 DOI: 10.1364/boe.489054] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 10/07/2023]
Abstract
Corneal densitometry is a clinically validated method for objectively assessing the transparency of stroma. The technique is currently dominated by Scheimpflug technology. Still, optical coherence tomography (OCT), in which examination of the statistical properties of corneal speckle is undertaken, has also been considered to assess corneal densitometry. In-vivo, the stroma is observed via the epithelium. However, the effect of this external layer on stromal densitometry has not been considered as yet. This study aims to quantify the influence of epithelium integrity on corneal OCT densitometry. OCT images from eleven freshly enucleated porcine eyes before and after epithelial debridement were used. OCT densitometry was investigated at different stromal depths using four metrics of speckle statistics. Results indicate that there exist statistically significant differences in speckle statistics for a given stromal depth depending on the presence or absence of the epithelium. The estimation error in speckle statistics can reach over 20% depending on the stromal depth. The anterior stroma densitometry values are the ones most affected by epithelial integrity. In conclusion, if OCT densitometry stromal parameters are to be considered in absolute terms, it is essential to consider the confounding effect of the epithelial layer in the analysis.
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Affiliation(s)
- Maria Miażdżyk
- Department of Biomedical Engineering,
Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
- Aragon Institute for Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - D. Robert Iskander
- Department of Biomedical Engineering,
Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
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13
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Chen L, Chen X, Li F, Liu Z. Refractive surprise of irregular astigmatism following cataract surgery in two patients with neglected subclinical corneal ectasia: two case reports. BMC Ophthalmol 2023; 23:239. [PMID: 37248492 DOI: 10.1186/s12886-023-02984-4] [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: 11/27/2022] [Accepted: 05/22/2023] [Indexed: 05/31/2023] Open
Abstract
BACKGROUND Corneal ectatic diseases are a group of corneal disorder characterized by the steepening and thinning of the cornea. Older people are not a high-risk population for corneal ectatic diseases; due to the lack of typical preoperative topographic manifestations, there is a high possibility that corneal ectasia is undetected. CASE PRESENTATION Two patients with subclinical corneal ectasia and senile cataracts presented with irregular astigmatism after steep-axis incision during cataract surgery. The two cases presented in this case report are rare because both patients experienced tremendous changes in astigmatism after cataract surgery. CONCLUSION This case report may shed some light on astigmatism-correcting steep-axis incisions in cataract surgeries.
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Affiliation(s)
- Leran Chen
- Department of Ophthalmology, Peking University Third Hospital, Beijing key laboratory of restoration of damaged ocular nerve, Beijing, 100191, China
| | - Xiaoyong Chen
- Department of Ophthalmology, Peking University Third Hospital, Beijing key laboratory of restoration of damaged ocular nerve, Beijing, 100191, China
| | - Fanshu Li
- Department of Ophthalmology, Peking University Third Hospital, Beijing key laboratory of restoration of damaged ocular nerve, Beijing, 100191, China
| | - Ziyuan Liu
- Department of Ophthalmology, Peking University Third Hospital, Beijing key laboratory of restoration of damaged ocular nerve, Beijing, 100191, China.
- Peking University Institute of Laser Medicine, Beijing, China.
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14
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Gustafsson I, Bizios D, Ivarsen A, Hjortdal JØ. The intra- and inter-day repeatability of corneal densitometry measurements in subjects with keratoconus and in healthy controls. Sci Rep 2023; 13:5566. [PMID: 37019974 PMCID: PMC10076276 DOI: 10.1038/s41598-023-32822-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 04/03/2023] [Indexed: 04/07/2023] Open
Abstract
The healthy cornea is transparent, however, disease can affect its structure, rendering it more or less opaque. The ability to assess the clarity of the cornea objectively could thus be of considerable interest for keratoconus patients. It has previously been suggested that densitometry can be used to diagnose early keratoconus, and that the values of densitometry variables increase with increasing disease severity, indicating that densitometry could also be used to assess progressive keratoconus. Previous studies have only assessed the repeatability of corneal densitometry measurements on the same day, which does not reflect the clinical setting in which changes are evaluated over time. We have therefore evaluated the inter-day repeatability of densitometry measurements in both patients with keratoconus and healthy controls. Measurements in the middle layer of the 2-6 mm zone of the cornea showed the best repeatability. Although an objective measure of the corneal transparency could be interesting, the generally poor repeatability of densitometry measurements limits their use. The repeatability of corneal clarity measurements could be improved by using other approaches such as optical coherence tomography, but this remains to be investigated. Such improvements would allow the more widespread use of corneal densitometry in clinical practice.
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Affiliation(s)
- Ingemar Gustafsson
- Department of Clinical Sciences, Ophthalmology, Lund University, Lund, Sweden.
- Department of Ophthalmology, Skåne University Hospital, Kioskgatan 1 , 221 85, Lund, Sweden.
| | - Dimitrios Bizios
- Department of Clinical Sciences, Ophthalmology, Lund University, Lund, Sweden
| | - Anders Ivarsen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Jesper Ø Hjortdal
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
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15
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Villanueva C, Viviano F, García-Montero M, Lorente-Velázquez A, Martínez-Alberquilla I, Garzón N. Forward-scattered and backward-scattered light in moderate keratoconus. Ophthalmic Physiol Opt 2023. [PMID: 36920155 DOI: 10.1111/opo.13126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 02/17/2023] [Accepted: 03/01/2023] [Indexed: 03/16/2023]
Abstract
INTRODUCTION To evaluate the backscattered light, objective scatter index (OSI) and retinal straylight in patients with moderate keratoconus and healthy control subjects. METHODS A prospective observational study was developed with 33 patients in the moderate-keratoconus group (KC) and 34 in the non-keratoconus group (NKC). Corneal densitometry was obtained using Scheimpflug corneal tomography and measurements were expressed in grayscale units (GSU) over four zones within a 12.00 mm diameter around the corneal apex. A straylight meter was used to determine the amount of intraocular straylight under scotopic conditions, and the straylight parameter (LOG(s)) and test duration were recorded. The Optical Quality Analysis System based on the double-pass technique determined the OSI value. RESULTS Significant differences were observed between the KC and NKC groups for corneal densitometry (except in the 6-10 mm zone), OSI and retinal straylight. A moderate and significant correlation was found between OSI and retinal straylight LOG(s) (r = 0.52, p = 0.002). Weaker and non-significant correlations were found between corneal densitometry and the other parameters analysed (i.e., OSI, retinal straylight LOG(s) and retinal straylight times). CONCLUSIONS Backscattered light, retinal straylight and the OSI show clear differences between healthy eyes and those with moderate KC. The changes present in the stages of KC evaluated in the current study (stages II and III according to the Amsler-Krumeich classification) might alter the scattering of the light entering the eye.
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Affiliation(s)
- Celia Villanueva
- Optometry and Vision Department, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain.,Ophthalmology Department, Hospital Clínico San Carlos, Madrid, Spain
| | - Francesco Viviano
- Optometry and Vision Department, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - María García-Montero
- Optometry and Vision Department, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Amalia Lorente-Velázquez
- Optometry and Vision Department, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Irene Martínez-Alberquilla
- Optometry and Vision Department, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Nuria Garzón
- Optometry and Vision Department, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
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16
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Chou CC, Shih PJ, Jou TS, Hsu MY, Chen JP, Hsu RH, Lee NC, Chien YH, Hwu WL, Wang IJ. Corneal Biomechanical Characteristics in Osteogenesis Imperfecta With Collagen Defect. Transl Vis Sci Technol 2023; 12:14. [PMID: 36622688 PMCID: PMC9838590 DOI: 10.1167/tvst.12.1.14] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Purpose To identify the characteristic corneal biomechanical properties of osteogenesis imperfecta (OI), and to compare the corneal biomechanical properties between OI and keratoconus. Methods We included 46 eyes of 23 patients with OI, 188 eyes of 99 keratoconus patients, and 174 eyes of 92 normal controls to compare corneal biomechanical parameters between OI corneas, keratoconus, and normal controls by using Corneal Visualization Scheimpflug Technology (Corvis ST). Results Patients with OI had significantly higher Corvis biomechanical index (CBI) (P < 0.001), higher tomographic and biomechanical index (TBI) (P = 0.040), lower Corvis Biomechanical Factor (CBiF) (P = 0.034), and lower stiffness parameter at first applanation (SP-A1) (P < 0.001) compared with normal controls. In contrast, OI group showed lower CBI (P < 0.001), lower TBI (P < 0.001), higher CBiF (P < 0.001), and higher SP-A1 (P = 0.020) than keratoconus group. Notably, the stress-strain index (SSI) was not significantly different between the OI and normal controls (P = 1.000), whereas keratoconus showed the lowest SSI compared with OI group (P = 0.025) and normal controls (P < 0.001). Conclusions Although the corneal structures of OI patients are less stable and easier to deform as compared to those of the control group, there is no significant difference in material stiffness observed between the OI and normal controls. In contrast, the corneas of keratoconus showed not only lower structural stability and higher deformability but also lower material stiffness compared with those of OI cornea and normal controls. Translational Relevance The biomechanical alterations are different between OI corneas and keratoconus.
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Affiliation(s)
- Chien-Chih Chou
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan,Department of Ophthalmology, Taichung Veterans General Hospital, Taichung, Taiwan,Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Po-Jen Shih
- Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Tzuu-Shuh Jou
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Min-Yen Hsu
- School of Medicine, Chung Shan Medical University, Taichung, Taiwan,Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Jun-Peng Chen
- Biostatistics Task Force of Taichung Veterans General Hospital, Taichung, Taiwan
| | - Rai-Hseng Hsu
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan,Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Ni-Chung Lee
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan,Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Yin-Hsiu Chien
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan,Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Wuh-Liang Hwu
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan,Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - I-Jong Wang
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan,Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
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17
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Consejo A, Trillo-Moreno I, Remon L. Corneal tissue changes following short-term soft contact lens wear of different materials. Ophthalmic Physiol Opt 2023; 43:35-45. [PMID: 36408647 PMCID: PMC10099478 DOI: 10.1111/opo.13067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/11/2022] [Accepted: 10/24/2022] [Indexed: 11/22/2022]
Abstract
PURPOSE To study the effect of different soft contact lens (CL) materials during short-term wear on corneal tissue. METHODS Twenty-two healthy participants wore both silicone hydrogel (MyDay, CooperVision) and hydrogel soft CLs (Biomedics 1 day extra, CooperVision) for 8 h per lens. In each session, Scheimpflug images were captured before and immediately after CL removal. Images were analysed using the densitometry distribution analysis, a technique from which two parameters, α (corneal transparency) and β (corneal homogeneity), were estimated. In addition, the central corneal thickness changes after CL wear and the influence of the CL material on corneal transparency were evaluated. RESULTS The β parameter (homogeneity) increased by 5% after wearing both CL materials (paired t-test, p < 0.001). However, the α parameter (transparency) only increased in half of the participants. No material was found to be more determinant in causing the corneal densitometry changes. Statistically significant but not clinically relevant changes in corneal thickness were observed. CONCLUSIONS Biomarkers of corneal tissue integrity (α and β) were affected by short-term soft contact lens wear. The observed changes in corneal transparency and homogeneity were not clinically relevant but support the importance of participant-material biocompatibility.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | | | - Laura Remon
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
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18
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Miażdżyk M, Consejo A, Iskander DR. Assessing and compensating for the confounding factors in Scheimpflug-based corneal densitometry. BIOMEDICAL OPTICS EXPRESS 2022; 13:6258-6272. [PMID: 36589572 PMCID: PMC9774844 DOI: 10.1364/boe.473534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/17/2022] [Accepted: 10/17/2022] [Indexed: 06/17/2023]
Abstract
Scheimpflug-based corneal densitometry is a clinically verified method for assessing corneal transparency. Nevertheless, the estimates of corneal densitometry appear to be correlated with age and eye biometry parameters, such as the anterior chamber depth or the pupil size, and that ensues a convoluted conditional estimation problem, where it is difficult to interpret the results. This study aims at devising a methodology for compensating for such confounding factors by using, as a research platform, a commercially available Scheimpflug camera that allows exporting images in a dynamic fashion, allowing averaging the results from multiple acquisitions. Two approaches are considered, one based on appropriately normalizing the line densitometry signal and one based on image histogram equalization. Then, three parameters for describing corneal densitometry are derived including the mean value of backscatter and the scale and shape parameters of the Weibull distribution estimated in regions of interest encompassing parts of corneal stroma. The results show that, unlike the non-normalized measures, the proposed approaches lead to parameters that are not correlated with age nor the eye biometry.
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Affiliation(s)
- Maria Miażdżyk
- Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - D. Robert Iskander
- Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
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19
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Mohebbi M, Samavat B, Mohammadi A. One-year non-comparative observational study to evaluate corneal tomographic, densitometric, and aberrometric features following accelerated corneal cross-linking in progressive keratoconus. Int Ophthalmol 2022; 43:1721-1735. [PMID: 36418804 DOI: 10.1007/s10792-022-02572-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/12/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the 12 months' changes in tomographic, densitometric, and aberrometric parameters in keratoconic eyes after accelerated corneal cross-linking (CCL) and classify a densitometric course in different stages of the keratoconus separately (mild, moderate, and severe). METHODS In a prospective observational study, 67 keratoconic eyes of 67 patients that underwent accelerated epithelium-off corneal cross-linking (9 mW/cm2 and 10 min) for treatment of progressive keratoconus were included. Corneal tomographic, densitometric, and aberrometric values obtained using the Pentacam HR were recorded at the baseline and 3, 6, and 12 months post-operatively. RESULTS One year after treatment, corrected distance visual acuity (CDVA) was improved, and maximum keratometry, thinnest pachymetry, higher order, and total root mean square (RMS) were significantly decreased (p < 0.001). Corneal densitometry values showed a significant elevation 3 months post-surgery compared to baseline and then decreased to baseline values at 1 year. Only the Anterior 0-2 mm zone densitometry at the 3rd month was different between the three groups. RMS at 1 year correlated with Anterior 0-2 mm, Anterior 2-6 mm, total corneal 0-2 mm, and total corneal 2-6 mm densitometry values in the 3rd month. Final CDVA at 12th month follow-up correlated with the Anterior 0-2 mm corneal densitometry in the 3rd month. CONCLUSION Anterior 0-2 mm zone densitometry at the 3rd-month post-accelerated CCL is different in various stages of keratoconus. Due to the correlation between final aberrometric and peak densitometric values in keratoconic eyes, peak densitometric values can be used as a prognostic factor for the final visual outcomes after accelerated CCL.
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20
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Consejo A, Jiménez-García M, Rozema JJ, Abass A. Influence of eye tilt on corneal densitometry. Ophthalmic Physiol Opt 2022; 42:1032-1037. [PMID: 35708180 PMCID: PMC9543421 DOI: 10.1111/opo.13020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE To investigate whether Pentacam densitometry readings are affected by corneal tilt. METHODS In a prospective study, the right eyes of 86 healthy participants aged 42.8 ± 20.0 years (range 18-79 years) were imaged using Scheimpflug tomography. Elevation maps were exported to calculate corneal tilt using custom-made software, and densitometry readings were acquired directly from the corneal densitometry analysis add-on to the standard software Oculus Pentacam HR. Simple mediation analysis was applied to study age as a confounding factor in the correlation between corneal tilt and corneal densitometry. RESULTS Corneal tilt and corneal densitometry are not independent from one another because age is significantly correlated with both corneal tilt (r = 0.50, p < 0.001) and corneal densitometry (r = 0.91, p < 0.001). Only 3.8% of the correlation between tilt and densitometry operates directly, while the remaining 96.2% depends on age. CONCLUSIONS Corneal tilt plays a role in corneal densitometry readings, even though the interaction is strongly influenced by age. Age is a well-known factor in densitometry readings that should be taken into consideration when interpreting Scheimpflug densitometry.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - Marta Jiménez-García
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Visual Optics Lab Antwerp (VOLANTIS), Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Jos J Rozema
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Visual Optics Lab Antwerp (VOLANTIS), Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Ahmed Abass
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, UK.,Department of Production Engineering and Mechanical Design, Faculty of Engineering, Port Said University, Port Said, Egypt
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21
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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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22
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Zhao L, Jing L, Li J, Du X. Changes in corneal densitometry after long-term orthokeratology for myopia and short-term discontinuation. PLoS One 2022; 17:e0263121. [PMID: 35120161 PMCID: PMC8815901 DOI: 10.1371/journal.pone.0263121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 01/12/2022] [Indexed: 11/18/2022] Open
Abstract
Purpose
To quantify changes in corneal densitometry after long-term orthokeratology treatment in myopic children and to analyze the reversibility one month after discontinuation.
Methods
Seventy-four myopic subjects aged 8–16 years, who wore orthokeratology lenses for two years, were divided into relatively steep- (lens movement within 1.0–1.5 mm, thirty-six participants) and flat-fitting groups (lens movement within 1.5–2.0 mm, thirty-eight participants). Based on refractive errors, they were divided into low and moderate myopia groups (thirty-seven participants in each group). Corneal densitometry was performed using Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) at each follow-up timepoint. Repeated-measures analysis of variance was used to compare the parameters before and after orthokeratology.
Results
The corneal densitometry values over the 0–10 mm diameter area increased from 12.84±1.38 grayscale units (GSU) at baseline to 13.59±1.42 GSU after three-month orthokeratology (P = .001) and reached 14.92±1.45 GSU at two years (P < .001). An increase in densitometry began at one month (P = .001) over the 0–2 mm annulus compared with that at three months over the 2–6 mm and 6–10 mm zones (P = .002,.014). The densitometry values significantly increased at three months in the relatively steep-fitting group (P = .003) and at one year in the relatively flat-fitting group (P = .001). After discontinuation of orthokeratology for one month, the values showed no significant decrease.
Conclusions
Long-term orthokeratology treatment causes a small but statistically significant increase in corneal densitometry values. During the first year, the onset of these changes was related to the fitting mode. Corneal densitometry values showed no significant reduction after one-month discontinuation.
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Affiliation(s)
- Lianghui Zhao
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, China
- Weifang Medical University, Weifang, China
| | - Lili Jing
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, China
| | - Jie Li
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, China
| | - Xianli Du
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, China
- * E-mail:
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23
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Toprak I, Gunes CE. Increased epithelial backscatter: A novel finding in subclinical and clinical keratoconus. Clin Exp Ophthalmol 2021; 49:1000-1008. [PMID: 34472198 DOI: 10.1111/ceo.13996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/11/2021] [Accepted: 08/30/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND To assess alterations in backscatter from the corneal epithelium, anterior stroma and lens surface in eyes with subclinical, mild and moderate keratoconus (KC). METHODS In this single-centre, cross-sectional study involving 24 eyes with subclinical KC, 107 eyes with manifest KC (mild = 40 and moderate = 67 eyes) and 90 controls, line densitometry was performed with Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) to obtain simultaneous backscatter values for the corneal epithelium, anterior stroma and anterior lens surface. Backscatter values and Pentacam parameters were used in subsequent statistical analyses. RESULTS Eyes with subclinical, mild and moderate KC had similar epithelial and stromal backscatter (P > 0.05) that was significantly increased compared with the controls (P < 0.05). Although anterior lens surface backscatter did not differ between the control and KC groups (P > 0.05), it was significantly higher in the mild and moderate KC groups than in the subclinical KC group (P < 0.05). In the KC group (n = 131) epithelial backscatter was strongly correlated with stromal backscatter (r = 0.911, P < 0.0001). CONCLUSIONS Increased epithelial backscatter and a strong correlation with anterior stromal backscatter in the KC groups were consistent with the epithelium-stroma interaction involved in KC pathogenesis. Single-point backscatter analysis can be used with point clouds to construct epithelial and stromal backscatter maps in Pentacam to aid the detection of KC as a novel feature.
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Affiliation(s)
- Ibrahim Toprak
- Department of Ophthalmology, Faculty of Medicine, Pamukkale University, Denizli, Turkey
| | - Celal Emre Gunes
- Department of Ophthalmology, Faculty of Medicine, Pamukkale University, Denizli, Turkey
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Consejo A, Jiménez-García M, Issarti I, Rozema JJ. Detection of Subclinical Keratoconus With a Validated Alternative Method to Corneal Densitometry. Transl Vis Sci Technol 2021; 10:32. [PMID: 34436543 PMCID: PMC8399563 DOI: 10.1167/tvst.10.9.32] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Purpose To enhance the current standards of subclinical keratoconus screening based on the statistical modeling of the pixel intensity distribution of Scheimpflug images. Methods Scheimpflug corneal tomographies corresponding to 25 corneal meridians of 60 participants were retrospectively collected and divided into three groups: controls (20 eyes), subclinical keratoconus (20 eyes), and clinical keratoconus (20 eyes). Only right eyes were selected. After corneal segmentation, pixel intensities of the stromal tissue were statistically modeled using a Weibull probability density function from which parameter α (pixel brightness) was derived. Further, data were transformed to polar coordinates, smoothed, and interpolated to build a map of the corneal α parameter. The discriminative power of the method was analyzed using receiver operating characteristic curves. Results The proposed platform-independent method achieved a higher performance in discriminating subclinical keratoconus from control eyes (90.0% sensitivity, 95.0% specificity, 0.97 area under the curve [AUC]) than the standard method (Belin-Ambrósio enhanced ectasia display), which uses only corneal morphometry (85.0% sensitivity, 85.0% specificity, 0.80 AUC). Conclusions Analysis of light backscatter at the cornea successfully discriminates subclinical keratoconus from control eyes, upgrading the results previously reported in the literature. Translational Relevance The proposed methodology has the potential to support clinicians in the detection of keratoconus before showing clinical signs.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain.,Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Marta Jiménez-García
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Ikram Issarti
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Jos J Rozema
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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Rodrigues PF, Moscovici BK, Ferrara G, Lamazales L, Freitas MMS, Torquetti L, Ambrósio R, Gomes JAP. Corneal densitometry in patients with keratoconus undergoing intrastromal Ferrara ring implantation. Eur J Ophthalmol 2021; 31:3505-3510. [PMID: 34058904 DOI: 10.1177/11206721211020631] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Evaluation of central corneal densitometry changes following Ferrara corneal ring segment implantation in patients with keratoconus, especially the correlation between corneal densitometry and keratometry. METHODS Retrospective, non-comparative, interventional study based on the review of medical records of patients diagnosed with keratoconus who underwent Ferrara corneal ring segment implantation. Pre and post-operative corneal densitometry measurements obtained with Pentacam HR (Oculus, Wetzlar, Germany) were analyzed. The follow-up time was 3 months, and data comparison was made, using specific statistical analysis, with the data of 3 months postoperatively. RESULTS The study sample consisted of 43 eyes of 36 patients. The mean corrected visual acuity improved from 0.82 LogMAR preoperatively (SD ± 0.33) to 0.19 LogMAR (SD ± 0.13) postoperatively. The mean spherical equivalent varied from -4.63 (SD ± 3.94) preoperatively to -2.16 (SD ± 2.63) postoperatively. Asphericity varied from -0.69 (SD ± 0.32) preoperatively to -0.27 (SD ± 0.31) postoperatively. The mean maximum K was 54.01D (SD ± 3.38) preoperatively and 51.50D (SD ± 2.90) postoperatively. The mean anterior densitometric value was 18.26 (SD ± 2.03) preoperatively and 17.66 (SD ± 1.84) postoperatively. CONCLUSION Corneal densitometry is an interesting technology that should be studied in keratoconus patients. Our results suggest that the corneal densitometry in the cornea's anterior layer reduces after ICRS implantation and correlates with corneal keratometry. Further studies should be performed to increase the knowledge in this field.
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Affiliation(s)
- Pablo Felipe Rodrigues
- Escola Paulista de Medicina, Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil.,Instituto Suel Abujamra, São Paulo, Brazil
| | | | | | | | | | | | - Renato Ambrósio
- Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
| | - José Alvaro Pereira Gomes
- Escola Paulista de Medicina, Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil.,Instituto Suel Abujamra, São Paulo, Brazil
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Ozkan HH, Koc M, Kiziltoprak H, Tekin K, Aydemir E. Evaluation of topographic, tomographic, topometric, densitometric, and aberrometric features of cornea with pentacam HR system in subclinical keratoconus. Int Ophthalmol 2021; 41:1729-1741. [PMID: 33772701 DOI: 10.1007/s10792-021-01732-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 01/30/2021] [Indexed: 12/27/2022]
Abstract
PURPOSE To investigate topographic, tomographic, topometric, densitometric, and aberrometric parameters in subclinical keratoconus with the Pentacam HR imaging system. METHODS Data of 3128 patients were evaluated, finding in 108 patients clinical keratoconus in one eye and subclinical keratoconus in the other. Corneal topographic, tomographic, topometric, densitometric, and aberrometric values obtained using the Pentacam HR imaging system were compared between clinical keratoconus, subclinical keratoconus, and normal eyes. RESULTS Comparing eyes with subclinical keratoconus and the control group, while flat K, horizontal coma, horizontal trefoil, and vertical trefoil values were similar (p > 0.05 for each), all other parameters were significantly different (p < 0.05 for each). Densitometry values of eyes with subclinical keratoconus were significantly higher in all layers of the 0-2 mm annular area and in the anterior and central layers of the 2-6 mm annular area compared to the control group (p < 0.05 for each). According to the receiver operating characteristic curve analysis, the densitometry region with the largest area under the curve was the anterior layer of the 0-2 mm annular area. The sensitivity in this region was 79.4% and the specificity 73.2% in distinguishing eyes with subclinical keratoconus from normal eyes when 19.3 GSU was considered the threshold. CONCLUSION Corneal densitometry values in the 0-2 and 2-6 mm annular areas, especially in the anterior layers, are parameters that can be used to predict and distinguish subclinical keratoconus from normal eyes.
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Affiliation(s)
- Haci Hasan Ozkan
- Ophthalmology Department, Ankara Occupational and Environmental Diseases Hospital, Ankara, Turkey.
| | - Mustafa Koc
- Ophthalmology Department, Kayseri Mayagoz Hospital, Kayseri, Turkey
| | - Hasan Kiziltoprak
- Ophthalmology Department, Adiyaman University Faculty of Medicine, Adiyaman, Turkey
| | - Kemal Tekin
- Ophthalmology Department, Hatay Mustafa Kemal University Faculty of Medicine, Hatay, Turkey
| | - Emre Aydemir
- Ophthalmology Department, Adıyaman Training and Research Hospital, Adıyaman, Turkey
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Jiménez-García M, Ní Dhubhghaill S, Hershko S, Koppen C, Rozema JJ. Densitometry marks delineating the affected area in keratoconus: clinical suitability of a new descriptive system based on its repeatability and reproducibility. Ophthalmic Physiol Opt 2021; 41:748-756. [PMID: 33860971 DOI: 10.1111/opo.12821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 01/31/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE To present a descriptive system for the elliptic demarcation area seen in keratoconus densitometry maps (obtained with a Scheimpflug tomographer) and to evaluate its suitability for clinical practice. METHODS The subjects were 30 keratoconus patients at different stages and 20 healthy subjects. The averaged densitometry maps ('two-layers' scan, with fixed layers 120 µm and endothelium) were analysed using a system of four categories (termed 'Brightness', 'Contrast', 'Decentration' and 'Octants surrounded by a dark line') that we created to characterise the demarcation area. Four examiners (three corneal specialists and one junior resident) used the system to classify the maps. The inter-rater agreement was calculated for two subgroups: (1) clinical keratoconus patients and (2) both healthy patients and forme fruste keratoconus patients. Intra-rater agreement was also determined. RESULTS Inter-rater agreement on classification was higher when analysing clinical keratoconus, reaching levels of substantial agreement. Despite this, only low levels of agreement were found in 'Decentration', penalized due to the skewness in the distribution of this descriptor. Almost perfect intra-rater agreement was obtained for all descriptors in the first subgroup of clinical keratoconus, whereas the agreement was generally moderate within the second subgroup of normal and forme fruste eyes. Agreement was slightly lower with the less experienced observer. At least three observers agreed on four forme fruste keratoconus eyes presenting abnormalities in the images. The observers reported that the 'Brightness' descriptor was subjective and redundant with 'Contrast'. CONCLUSIONS The description of the area was repeatable and reproducible, and may be a valuable supplement when documenting clinical keratoconus stage and progression in daily practice. However, a minor learning curve was noticed and agreement was higher among the more experienced observers. Since the descriptor 'Brightness' was found to be subjective and redundant, it was excluded from the final proposed classification.
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Affiliation(s)
- Marta Jiménez-García
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Sorcha Ní Dhubhghaill
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Sarah Hershko
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Carina Koppen
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Jos J Rozema
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium.,Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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Cox AR, Sia RK, Purt B, Ryan DS, Beydoun H, Colyer MH, Rivers BA, Bower KS. Assessment of Corneal Haze After PRK and the Effect of Sutureless Amniotic Membrane Graft by Corneal Densitometry. J Refract Surg 2021; 36:293-299. [PMID: 32396640 DOI: 10.3928/1081597x-20200406-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 04/02/2020] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess whether densitometry analysis appropriately monitors the development of haze in myopic patients after photorefractive keratectomy (PRK) when compared to subjective slit-lamp haze grade examinations, and whether sutureless cryo-preserved amniotic membrane reduced postoperative haze development when compared to the standard bandage contact lens. METHODS In this retrospective cohort at the Center for Refractive Surgery, Walter Reed National Military Medical Center, a secondary analysis of prospectively collected data was performed. In the prospective study, participants underwent PRK for myopia. Postoperatively, a standard bandage contact lens was applied to the dominant eye and a sutureless cryo-preserved amniotic membrane graft to the nondominant eye. Participants were evaluated at 1, 3, and 6 months postoperatively for haze formation and corneal densitometry using slit-lamp biomicroscopy and Scheimpflug imaging, respectively. RESULTS Densitometry measurements at 6 months postoperatively were positively and significantly associated with the presence or absence of haze as assessed by slit-lamp examination in 39 patients (78 eyes; age range: 21 to 44 years). Eyes with increased densitometry measurements had 2.3 to 3.4 times the odds (P ⩽ .014) of having clinical haze on slit-lamp examination. Eyes with the amniotic membrane graft showed a positive correlation with increased corneal densitometry throughout most layers of the cornea. CONCLUSIONS Densitometry analysis appears to be a useful tool to supplement slit-lamp examination in monitoring haze development after PRK. The amniotic membrane failed to show a reduction in corneal densitometry in myopic eyes after PRK. [J Refract Surg. 2020;36(5):293-299.].
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Jabbarvand M, Khodaparast M, Jamali A, Ahmadzadeh H, Bordbar S. Changes in the Optical Corneal Densitometry, Visual Acuity, and Refractive Error after the Annular Intracorneal Inlay Implantation. J Curr Ophthalmol 2021; 33:23-30. [PMID: 34084953 PMCID: PMC8102947 DOI: 10.4103/joco.joco_154_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 09/04/2020] [Accepted: 09/29/2020] [Indexed: 11/17/2022] Open
Abstract
Purpose: To investigate the changes in the optical corneal densitometry as an objective method in assessing the corneal light back-scattering before and 1 year after the annular intracorneal inlay (AICI) implantation into the keratoconic corneas. Methods: Changes in the optical corneal densitometry, visual acuity, refractive, and tomographical status were assessed before and 1 year after the AICI implantation into the corneas with different stages of keratoconus. Optical corneal densitometry was evaluated using the Pentacam-HR in 0–2, 2–6, 6–10, and 10–12 mm rings in the anterior 120 μ, central layers, posterior 60 μ and also the total value were measured for cornea in the Grey Scale Unit criterion. Results: Totally, 34 patients with keratoconus were studied; the uncorrected and best corrected visual acuity were increased after the surgery (0.98 ± 0.25 to 0.53 ± 0.30 logMAR, P < 0.001 and 0.26 ± 0.18 to 0.19 ± 0.14, P = 0.007 logMAR, respectively); the spherical equivalent was decreased from −4.45 ± 2.25 to − 2.06 ± 2.01 D (P = 0.004). AICI implantation led to an increase in the amount of optical corneal densitometry in 0–2 mm central, 2–6 mm central, 6–10 mm central, total central, 2–6 mm posterior, and 2–6 mm total rings (all, P < 0.05); however, a decrease was observed in 0–2 mm anterior ring (P = 0.049). Results of statistical analysis showed that the total optical corneal densitometry, anterior total, and posterior total back-scattering did not change after the AICI implantation (all, P > 0.05). Conclusions: Our results revealed a significant improvement in the visual function, including refractive error and visual acuity following the AICI implantation. Changes in the optical corneal densitometry were different in distinct regions and layers however, the total amount did not change after the AICI implantation.
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Affiliation(s)
- Mahmoud Jabbarvand
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Khodaparast
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Jamali
- Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Hooman Ahmadzadeh
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Soodeh Bordbar
- English Department, Iran University of Medical Sciences, Tehran, Iran
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Corneal and lens densitometry in patients with vernal keratoconjunctivitis. Int Ophthalmol 2021; 41:2667-2676. [PMID: 33754236 PMCID: PMC7983973 DOI: 10.1007/s10792-021-01822-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/16/2021] [Indexed: 10/25/2022]
Abstract
AIM To evaluate corneal and crystalline lens densitometry in patients with vernal keratoconjunctivitis (VKC). METHODS This is a case-control study. Patients with VKC and age-gender-matched healthy controls underwent a complete ophthalmologic examination with corneal and crystalline lens densitometry measurements. Additionally, the anterior chamber parameters comprise anterior and posterior Kmean and astigmatism, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), pachymeter, and corneal volume (CV). Patients who had clinically grade 0 or grade 1 VKC and with only tarsal conjunctiva involvement during the conductance of the study were included. The variables were compared statistically. RESULTS One hundred and nine eyes were included in the study, in which fifty-one were in the VKC group. There were 25 males in the VKC group (26 female) and 22 males in the control group (36 female). A statistically significant difference was found between the groups in terms of posterior corneal astigmatism (p = 0.02). The mean corneal pachymeter, CV, ACD, ACA, and ACV were similar in both groups (p = 0.63, p = 0.26, p = 0.60, p = 0.41, and p = 0.32, respectively). The total mean corneal densitometry in the zones extending from 6 to 10 mm and 10 to 12 mm was increased in the VKC group compared to the control group (p = 0.04 and p = 0.012, respectively). The mean crystalline lens was found to be denser in the VKC group compared to the control group (8.96 ± 1.6 vs. 8.5 ± 0.57, respectively, p = 0.04). CONCLUSION Posterior corneal astigmatism is increased in VKC cases in comparison with age- and gender-matched controls. The peripheral anterior 6-12 mm annular corneal zone showed increased corneal densitometry in VKC cases compared to the healthy subjects. Additionally, the lens clarity is found to be decreased subclinically in VKC cases compared to control cases.
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Jiménez-García M, Ní Dhubhghaill S, Consejo A, Hershko S, Koppen C, Rozema JJ. Scheimpflug Densitometry in Keratoconus: A New Method of Visualizing the Cone. Cornea 2021; 40:194-202. [PMID: 33065713 DOI: 10.1097/ico.0000000000002458] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/07/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE To report an observation made while performing Scheimpflug densitometry analysis on the corneal region affected in keratoconus (KC) that seems to delineate the base of the cone. METHODS Scheimpflug densitometries of 20 healthy subjects and 90 patients with KC were examined. Corneal densitometry was analyzed using both "1-layer" and "2-layer" approaches. The first considers the corneal transparency layer by layer at different depths, whereas the second averages densitometry between 2 corneal layers selected by the examiner. Fixed layers, 120 μm depth, and endothelium were selected. Repeated same-day scans and longitudinal series of scans were also evaluated to see whether the findings evolved over time. RESULTS Eighty-eight of 90 KC cases displayed a bright area on the densitometry map that corresponded to the cone location. The area's characteristics, such as its brightness, contrast, and the presence of a delimiting arc correlated with KC severity and was more noticeable in advanced cases. No similar marks were found in any of the normal subjects. The shape, location, and extent of the mark were consistent over consecutive measures taken on the same day. Changes over time were also seen in eyes with known clinical progression but was also seen in eyes considered clinically stable. CONCLUSIONS The densitometry mark seems to correspond with the zone most affected by KC and could be a supplementary tool for documenting KC stage, alongside conventional parameters. Further studies are required to ascertain whether it could prove useful in KC detection, to determine progression, and to relate it to corneal biomechanical behavior.
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Affiliation(s)
- Marta Jiménez-García
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium ; and
| | - Sorcha Ní Dhubhghaill
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium ; and
| | - Alejandra Consejo
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Sarah Hershko
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium ; and
| | - Carina Koppen
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium ; and
| | - Jos J Rozema
- Department of Ophthalmology, Antwerp University Hospital (UZA), Edegem, Belgium
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium ; and
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The evaluation of corneal topographic parameters with corneal and lens densitometers in pediatric keratoconus. Int Ophthalmol 2020; 41:541-548. [PMID: 33048254 DOI: 10.1007/s10792-020-01605-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 10/01/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE The aim of this study was to compare corneal and lens densitometric measurements and corneal topographic parameters of pediatric keratoconus patients and healthy individuals. METHODS The data of the Pentacam® HR device and the database of our hospital between 2017 and 2019 were analyzed retrospectively. A total of 80 eyes of 47 keratoconus children (one eye of 14 children and two eyes of 33 children) in the Group KC (n = 80); and 74 eyes of 37 children were assessed in healthy children, Group HC (n = 74). The corneal density was measured manually in full-thickness cornea with a diameter of 2 mm in the corneal apex. The lens density (LD) was measured manually in the pupillary area with a diameter of 2 mm throughout the whole central lens thickness in 3D mode. RESULTS The corneal density values were significantly higher in Group KC (12.72 ± 1.68, 1.00 ± 0.34, 16.36 ± 2.32, respectively) compared to Group HC (9.81 ± 1.02, 0.61 ± 0.28, 12.42 ± 1.44, respectively) (p < 0.001). LD-mean and LD-sd measurements were lower in Group KC (7.55 ± 0.48, 0.61 ± 0.49, respectively) compared to Group HC (7.75 ± 0.39, 0.81 ± 0.49, respectively) (p = 0.004, p = 0.014, respectively). CONCLUSION It was found that corneal density increased and lens density decreased in pediatric keratoconus patients. These results showed that there may be factors that prevent or delay lens changes in isolated pediatric keratoconus patients.
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Corneal Abnormalities Are Novel Clinical Feature in Wolfram Syndrome. Am J Ophthalmol 2020; 217:140-151. [PMID: 32335055 DOI: 10.1016/j.ajo.2020.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 04/12/2020] [Accepted: 04/14/2020] [Indexed: 02/02/2023]
Abstract
PURPOSE To evaluate corneal morphology among patients with Wolfram syndrome (WFS). DESIGN Comparative observational longitudinal case series of WFS patients with a laboratory approach in the WFS1 gene knockout (Wfs1KO) mouse model. METHODS A group of 12 patients with biallelic mutations in the WFS1 gene recruited from the whole country and a control group composed of 30 individuals with type 1 diabetes (T1D) were evaluated in a national reference center for monogenic diabetes. All subjects (n = 42) underwent a complete ophthalmic examination, computer videokeratography, and corneal thickness and endothelial measurements. Additionally, WFS patients (n = 9) underwent longitudinal videokeratography and Pentacam evaluation. Corneal characteristics were assessed and compared between both groups. Human and mouse corneas were subjected to immunohistochemistry to detect wolframin expression and microscopic evaluation to study corneal morphology ex vivo. RESULTS Clinical and topographic abnormalities similar to keratoconus were observed in 14 eyes (58.3%) of 8 WFS patients (66.7%). Flat keratometry, inferior-superior dioptric asymmetry, skewed radial axis, logarithm of keratoconus percentage index, index of surface variance, index of vertical asymmetry, keratoconus index, central keratoconus index, index of height asymmetry, and index of height decentration differed between WFS and T1D patients. Immunohistochemistry demonstrated wolframin expression in human and mouse corneas. Compared with Wfs1WT mice, Wfs1KO mice also presented corneal abnormalities. CONCLUSIONS Patients with WFS present a high prevalence of changes in corneal morphology compatible with the diagnosis of early stages of keratoconus. Observations in a mouse model suggest that a mutation in the WFS1 gene may be responsible for corneal abnormalities similar to keratoconus.
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Pillunat KR, Orphal J, Haase M, Pillunat LE, Herber R. Scheimpflug Corneal Densitometry Changes After Trabeculectomy. Cornea 2020; 40:408-414. [PMID: 32732700 DOI: 10.1097/ico.0000000000002439] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To study the possible changes in Scheimpflug corneal densitometry 6 months after mitomycin C-augmented trabeculectomy and to compare these measurements with healthy controls. METHODS Corneal densitometry was monitored with the Pentacam HR3 before and 6 months after first-time uncomplicated mitomycin C-augmented trabeculectomy in 42 eyes of 42 white patients with open-angle glaucoma and in 22 healthy age-matched controls. Preoperative intraocular pressure (IOP), central corneal thickness, known duration of the disease, gender, the type and number of substances, applications and amount of benzalkonium chloride per day, and postoperative topical cortisone use were tested for possible correlations in the trabeculectomy group. RESULTS There was a statistically significant reduction of mean diurnal IOP from 19.0 ± 7.7 to 11.1 ± 7.7 mm Hg (P = 0.003) and the amount of pressure-lowering substances from 3.7 ± 1.0 to 0.1 ± 0.5 (P < 0.001). Densitometry measurements decreased in the entire cornea from 25.5 ± 5.7 to 23.1 ± 5.8 grayscale units (P = 0.001) with emphasis in the anterior layer. They returned close to normal 6 months after trabeculectomy and were not statistically significantly different compared with a healthy control group (22.8 ± 3.4 grayscale unit; P = 0.824). No correlations could be found with these observations and possible causing factors studied. CONCLUSIONS Corneal densitometry, an objective and sensitive measure of corneal transparency, returned close to normal 6 months after trabeculectomy. Although the observations cannot be associated with any causing factor in this study, the significant IOP reduction and the nearly complete cessation of topical antiglaucomatous substances including benzalkonium chloride seem to be the most plausible reasons for this finding.
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Affiliation(s)
- Karin R Pillunat
- Department of Ophthalmology, Medical Faculty Carl Gustav Carus, Technische Universität, Dresden, Germany
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Anterior Segment Findings in Patients With Osteogenesis Imperfecta: A Case-Control Study. Cornea 2020; 39:935-939. [DOI: 10.1097/ico.0000000000002345] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Asgari S, Aghamirsalim M, Mehravaran S, Hashemi H. Effect of Down syndrome and keratoconus on corneal density and volume: a triple comparative study. Sci Rep 2020; 10:9098. [PMID: 32499561 PMCID: PMC7272627 DOI: 10.1038/s41598-020-66108-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/15/2020] [Indexed: 12/13/2022] Open
Abstract
Keratoconus (KCN) and Down syndrome affect the corneal density and volume. In this study included Down syndrome patients with and without KCN (24 Down-KCN and 204 Down-nonKCN eyes) and normal age- and gender-matched individuals (184 eyes). Studied parameters were the corneal density measured with Pentacam HR in 5 concentric zones and annuli (0-2 mm, 2-6 mm, 6-10 mm, 10-12 mm, and 0-12 mm) in 4 different depth layers (anterior 120 µm, posterior 60 µm, middle layer, and the full thickness of the cornea), and the 10 mm zone corneal volume. In Down-KCN, Down-nonKCN, and control groups, respectively, mean full thickness density in the 0-12 mm zone was 19.35 ± 2.92, 17.85 ± 2.55, and 15.78 ± 2.67 GSU, and mean corneal volume was 57.45 ± 4.37, 56.99 ± 3.46, and 61.43 ± 3.42mm3. All density readings were significantly different between the three studied groups (all P < 0.01) except full thickness density in 0-2 mm and 2-6 mm (P > 0.05) and corneal volume (P = 0.519) between Down-KCN and Down-nonKCN groups; these inter-group densitometry differences within the 6 mm zone were only in the middle layer, and not the anterior or posterior thickness layers (all P > 0.05). Corneal density increased with age and corneal thickness, but there was no significant relationship with gender. Overall, Down syndrome is associated with increased density and light scatter in all corneal layers up to the 12 mm diameter. In Down patients with KCN, the increased light scatter and density in the 6 mm zone is only in the middle thickness layer. Corneal volume is reduced in Down syndrome irrespective of the presence or absence of KCN.
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Affiliation(s)
- Soheila Asgari
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | | | - Shiva Mehravaran
- ASCEND Center for Biomedical Research, Morgan State University, Baltimore, MD, USA
| | - Hassan Hashemi
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
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Scheimpflug Corneal Densitometry Changes After the Intrastromal Corneal Ring Segment Implantation. Cornea 2020; 39:761-768. [DOI: 10.1097/ico.0000000000002307] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Koc M, Tekin K, Kiziltoprak H, Inanc M, Kosekahya P, Ozulken K, Durukan I. Topometric and Tomographic Evaluation of Subclinical Keratoconus. Ophthalmic Epidemiol 2020; 27:289-297. [PMID: 32172662 DOI: 10.1080/09286586.2020.1741010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To investigate the corneal topometric and tomographic findings that can be used in the diagnosis of subclinical keratoconus. METHODS A retrospective cohort study. The study group was selected from patients with clinically evident keratoconus in one eye and subclinical keratoconus without evident topographic findings in fellow eye. The age-matched control group was selected from patients who were candidates for laser in situ keratomileusis (LASIK) and did not develop ectasia after LASIK surgery at least 1-year follow-up. All subjects underwent topographic, topometric and tomographic (Belin-Ambrósio Enhanced Ectasia Display III) analyses via a Pentacam HR rotating Scheimpflug camera (Oculus, Germany, version 1.20r.98) before LASIK surgery. RESULTS The study group consisted of 151 patients (69 male and 82 female, mean age of 24.8 ± 7.2 years) and the control group also consisted of 150 patients (70 male and 80 female, mean age of 26.0 ± 6.3 years). There were statistically significant differences in all measured topometric (p˂.05) and tomographic (p˂.001) parameters between the eyes with subclinical keratoconus and those of the control group. In discriminating eyes with subclinical keratoconus from normal eyes, final D showed the highest area under curve value (0.858, sensitivity 85.2%, specificity 66.7%), followed by maximum pachymetric progression index (0.809, sensitivity 81.9%, specificity 69.4%) and average pachymetric progression index (0.796, sensitivity 81.9%, specificity 68.1%) in receiver operating characteristic analysis. CONCLUSION Topometric and tomographic parameters might be useful for early detection of keratoconus, but the sensitivity and specificity of any parameter are not high enough to be used alone.
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Affiliation(s)
- Mustafa Koc
- Ophthalmology Department, Ankara Ulucanlar Eye Training and Research Hospital , Ankara, Turkey
| | - Kemal Tekin
- Ophthalmology Department, Ercis State Hospital , Van, Turkey
| | - Hasan Kiziltoprak
- Ophthalmology Department, Ankara Ulucanlar Eye Training and Research Hospital , Ankara, Turkey
| | - Merve Inanc
- Ophthalmology Department, Ercis State Hospital , Van, Turkey
| | - Pinar Kosekahya
- Ophthalmology Department, Ankara Ulucanlar Eye Training and Research Hospital , Ankara, Turkey
| | - Kemal Ozulken
- Ophthalmology Department, TOBB ETU Hospital , Ankara, Turkey
| | - Irfan Durukan
- Ophthalmology department, Era Eye Hospital , Ankara, Turkey
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Koc M, Aydemir E, Tekin K, Inanc M, Kosekahya P, Kiziltoprak H. Biomechanical Analysis of Subclinical Keratoconus With Normal Topographic, Topometric, and Tomographic Findings. J Refract Surg 2019; 35:247-252. [PMID: 30984982 DOI: 10.3928/1081597x-20190226-01] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 02/26/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the corneal biomechanical responses of subclinical keratoconus with normal topographic, topometric, and tomographic findings. METHODS In this prospective observational study, the study group was selected from patients with clinically evident keratoconus in one eye and subclinical keratoconus with normal topographic, topometric, and tomographic findings in the fellow eye. The control group was selected from candidates for contact lens use. The biomechanical analyses were performed using the Corvis ST (Oculus Optikgeräte, Wetzlar, Germany). The following parameters were analyzed: A1 velocity, A2 velocity, A1 length, A2 length, deformation amplitude ratio, stiffness parameter at the first applanation, Corvis Biomechanical Index, and Tomographic and Biomechanical Index (TBI). RESULTS The study group consisted of 21 patients (10 men and 11 women; mean age: 27.7 ± 6.9 years), and the control group consisted of 35 patients (17 men and 18 women; mean age: 26.1 ± 5.8 years). No significant differences were found between the eyes with subclinical keratoconus and normal eyes in corrected distance visual acuity and the topographic, topometric, and tomographic parameters (P > .05). Significant differences were found in the values of A2 length, A1 velocity, A2 velocity, and TBI between the subclinical keratoconus group and the control group (P < .05). In distinguishing eyes with subclinical keratoconus from normal eyes, the TBI showed the highest area under the curve (0.790; cut-off: 0.29; sensitivity: 67%; specificity: 86%) in the receiver operating characteristic analysis. CONCLUSIONS Biomechanical analysis with the Corvis ST may be used as a complementary diagnostic method in detecting subclinical keratoconus. [J Refract Surg. 2019;35(4):247-252.].
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Steinberg J, Siebert M, Katz T, Frings A, Mehlan J, Druchkiv V, Bühren J, Linke SJ. Tomographic and Biomechanical Scheimpflug Imaging for Keratoconus Characterization: A Validation of Current Indices. J Refract Surg 2019; 34:840-847. [PMID: 30540367 DOI: 10.3928/1081597x-20181012-01] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 10/10/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE To analyze the potential benefit of the newly developed Tomography and Biomechanical Index (TBI) for early keratoconus screening. METHODS In this retrospective study, the discriminatory power of the corneal tomography Belin/Ambrósio Enhanced Ectasia Display (BAD-D) index and the newly developed Corvis Biomechanical Index (CBI) and TBI to differentiate between normal eyes, manifest keratoconus eyes (KCE), very asymmetric keratoconus eyes with ectasia (VAE-E), and their fellow eyes with either regular topography (VAE-NT) or regular topography and tomography (VAE-NTT) were analyzed by applying the t test (for normal distribution), Wilcoxon matched-pairs test (if not normally distributed), and receiver operating characteristic curve (ROC). The DeLong test was used to compare the area under the ROC (AUROC). Further, the cut-offs of the analyzed indices presented in a study by Ambrósio et al. from 2017 were applied in the study population to enable a cross-validation in an independent study population. RESULTS All indices demonstrated a high discriminative power when comparing normal and advanced keratoconus, which decreased when comparing normal and VAE-NT eyes and further when analyzing normal versus VAE-NTT eyes. The difference between the AUROCs reached a statistically significant level when comparing TBI versus BAD-D analyzing normal versus all included keratoconic eyes (P = .02). The TBI presented with the highest AUROCs throughout all conducted analyses when comparing different keratoconus stages, although not reaching a statistically significant level. Applying the cut-offs presented by Ambrósio et al. to differentiate between normal and VAE-NT in the study population, the accuracy was reproducible (accuracy in our study population with an optimized TBI cut-off: 0.72, with the cut-off defined by Ambrósio et al. 0.67). CONCLUSIONS The TBI enables karatoconus screening in topographical and tomographical regular keratoconic eyes. To further improve the screening accuray, prospective studies should be conducted. [J Refract Surg. 2018;34(12):840-847.].
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Koç M, Tekin K. Topography and Higher Order Corneal Aberrations of the Fellow Eye in Unilateral Keratoconus. Turk J Ophthalmol 2018; 48:274-275. [PMID: 30405952 PMCID: PMC6216537 DOI: 10.4274/tjo.65642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 08/31/2018] [Indexed: 12/01/2022] Open
Affiliation(s)
- Mustafa Koç
- Ulucanlar Eye Training and Research Hospital, Ophthalmology Clinic, Ankara, Turkey
| | - Kemal Tekin
- Erciş State Hospital, Ophthalmology Clinic, Van, Turkey
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