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Arnalich-Montiel F, Ortiz-Toquero S, Kandel H, Lewis N, Chiong Hong S, Downie N, Watson A, Abbondanza M, Watson S. Intereye Asymmetry as a Predictor of Progression in Patients With Untreated Keratoconus: Findings From a Longitudinal Study. Cornea 2024:00003226-990000000-00586. [PMID: 38913977 DOI: 10.1097/ico.0000000000003601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Indexed: 06/26/2024]
Abstract
PURPOSE The purpose of this study was to evaluate interocular predictors of progression in patients with untreated keratoconus. METHODS This is a multicenter longitudinal observational study with real-world data collected through the Save Sight Keratoconus Registry. Patients between the period of June 2000 and September 2022 were included in this study. Parameters such as patient age, sex, ocular history, visual acuity, K2, Max-K, and thinnest corneal thickness pachymetry (TCT) were analyzed. RESULTS There were 4342 untreated eyes from 2171 patients with keratoconus. A total of 333 patients showed progression of either Max-K, TCT, or both, whereas 1838 patients showed stable parameters. Factors associated with a higher incidence of progression in Max-K were younger baseline age (HR 0.96 per year older; 95% CI 0.95-0.98, P < 0.0001) and a higher baseline intereye asymmetry in Max-K (HR 1.02 per higher diopter; 95% CI 1.00-1.04, P = 0.04). A younger baseline age was the only predictor of progression in TCT (HR 0.97 per year older; 95% CI 0.95-0.99, P = 0.001). CONCLUSIONS Age is the most significant predictor of progression for both corneal thinning and progression of Max-K. Interocular asymmetry in Max-K at baseline could be used as part of an algorithm for determining the risk of keratoconus progression. It is recommended that patients with higher interocular asymmetry in Max-K have a closer follow-up of both eyes as they are at a higher risk of progression.
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Affiliation(s)
- Francisco Arnalich-Montiel
- Department of Ophthalmology, Cornea Unit, Ramón y Cajal University Hospital, Madrid, Spain
- School of Medicine, University CEU San Pablo, Madrid, Spain
| | - Sara Ortiz-Toquero
- Department of Ophthalmology, Cornea Unit, Ramón y Cajal University Hospital, Madrid, Spain
| | - Himal Kandel
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia
- Sydney Eye Hospital, Sydney, New South Wales, Australia
| | - Noni Lewis
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia
- Central Sydney Eye Surgeons, Sydney, New South Wales, Australia
| | - Sheng Chiong Hong
- Dunedin Public Hospital, Te Ora Whatu Southern, Dunedin, New Zealand
| | | | | | | | - Stephanie Watson
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia
- Sydney Eye Hospital, Sydney, New South Wales, Australia
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Vaccaro S, Vivarelli C, Yu AC, Pecora N, Lionetti G, Gioia R, Scorcia V, Giannaccare G. Longitudinal Changes of Cornea Volume Measured by Means of Anterior Segment-Optical Coherence Tomography in Patients with Stable and Progressive Keratoconus. Life (Basel) 2024; 14:176. [PMID: 38398685 PMCID: PMC10890364 DOI: 10.3390/life14020176] [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: 12/10/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
Keratoconus is a corneal disease which results in progressive thinning and protrusion of the cornea leading to irregular astigmatism. The purpose of this study was to evaluate longitudinal changes in corneal volume (CV) occurring over time in keratoconus eyes. Consecutive patients affected by keratoconus were evaluated by means of anterior segment-optical coherence tomography (AS-OCT) at two different time points: baseline (T0) and after 1 year (T1). Anterior and posterior refractive value; corneal thickness at the thinnest point (TP) and corneal volume (CV) calculated within discs of 3, 5 and 8 mm of diameter; anterior chamber depth (ACD); and anterior chamber volume (ACV) were obtained. Enrolled patients were divided into 3 groups (groups 1, 2, 3) according to the increasing disease severity and into 2 groups (groups A, B) according to the progression or stability of the disease. Overall, 116 eyes of 116 patients (76 males and 40 females, mean age 34.76 ± 13.99 years) were included. For the entire group of keratoconus patients, in comparison with T0, mean TP decreased at T1 from 458.7 ± 52.2 µm to 454.6 ± 51.6 µm (p = 0.0004); in parallel, mean value of CV calculated at 5 mm and 8 mm decreased significantly (from 10.78 ± 0.8 at T0 to 10.75 ± 0.79 at T1 (p = 0.02), and from 32.03 ± 2.01 mm3 at T0 to 31.95 ± 1.98 at T1 (p = 0.02), respectively). Conversely, there were no statistically significant differences in CV at 3 mm from T0 to T1 (p = 0.08), as well as for ACD and ACV. Regarding the course of the disease, patients belonging to group A showed statistically significant differences from T0 to T1 for TP, and for CV at 3 mm, 5 mm and 8 mm (p < 0.0001, p < 0.0001, p < 0.001 and p = 0.0058 respectively). There were no statistically significant differences for ACD (p = 0.6916) and ACV calculated at 3, 5 and 8 mm (p = 0.7709, p = 0.3765, p = 0.2475, respectively) in group A. At the same time, no statistically significant differences for ACD (p = 0.2897) and ACV calculated at 3, 5 and 8 mm (p = 0.9849, p = 0.6420, p = 0.8338, respectively) were found in group B. There were statistically significant positive correlations between changes of TP and CV at 3 mm (r = 0.6324, p < 0.0001), 5 mm (r = 0.7622, p < 0.0001) and 8 mm (r = 0.5987 p < 0.0001). In conclusion, given the strong correlation with TP, CV might be considered an additional AS-OCT parameter to be used in association with conventional parameters when detecting longitudinal changes in keratoconic eyes.
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Affiliation(s)
- Sabrina Vaccaro
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Chiara Vivarelli
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.V.); (A.C.Y.)
- Department of Ophthalmology, Ospedali Privati Forlì “Villa Igea”, 47122 Forlì, Italy
| | - Angeli Christy Yu
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.V.); (A.C.Y.)
- Department of Ophthalmology, Ospedali Privati Forlì “Villa Igea”, 47122 Forlì, Italy
| | - Nicolò Pecora
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Giovanna Lionetti
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Raffaella Gioia
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Vincenzo Scorcia
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Giuseppe Giannaccare
- Eye Clinic, Department of Surgical Sciences, University of Cagliari, Via Università 40, 09124 Cagliari, Italy
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Wu Y, Guo LL, Tian L, Xu ZQ, Li Q, Hu J, Huang YF, Wang LQ. Comparative analysis of the morphological and biomechanical properties of normal cornea and keratoconus at different stages. Int Ophthalmol 2021; 41:3699-3711. [PMID: 34232432 PMCID: PMC8536578 DOI: 10.1007/s10792-021-01929-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 06/19/2021] [Indexed: 11/07/2022]
Abstract
Purpose To compare the morphological and biomechanical properties of normal cornea and keratoconus at different stages. Methods A total of 408 patients (517 eyes) with keratoconus were included in this study. According to the Topographic Keratoconus (TKC) grading method, keratoconus was divided into stage I (TKC = 1, 130 eyes), stage II (TKC = 1–2, 2, 164 eyes), stage III (TKC = 2–3, 3, 125 eyes) and stage IV (TKC = 3–4, 4, 98 eyes). A total of 158 normal subjects (158 eyes) were recruited as the normal group. The corneal morphological parameters and biomechanical parameters were obtained with Scheimpflug tomography (Pentacam) and corneal visualization Scheimpflug technology (Corvis ST), and the receiver operating characteristic (ROC) curves were drawn. Results Each corneal morphological and most biomechanical parameters of the keratoconic eyes were significantly different from those of the normal eyes in this study (p < 0.001). ROC curve demonstrated that most parameters in this study showed high efficiency in diagnosing keratoconus (the area under the ROC (AUC) was > 0.9), with the Belin-Ambrósio deviation (BAD-D) and Tomographic and Biomechanical Index (TBI) showing higher efficiency. The efficiency of BAD-D and TBI was high in differentiating keratoconus at different stages (AUC > 0.963). The comparison of ROC curves of keratoconus at different stages did not reveal statistically significant differences for TBI. Conclusion BAD-D and TBI can effectively diagnose stage I keratoconus. Moreover, the efficiency of TBI is the same in diagnosing keratoconus at all stages, while the diagnostic efficiency of other parameters increases with the increase in keratoconus stages.
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Affiliation(s)
- Ying Wu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Li-Li Guo
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China. .,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, 100730, China.
| | - Ze-Quan Xu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Qian Li
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Jian Hu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Yi-Fei Huang
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Li-Qiang Wang
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China.
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Veerappa AM. Cascade of interactions between candidate genes reveals convergent mechanisms in keratoconus disease pathogenesis. Ophthalmic Genet 2021; 42:114-131. [PMID: 33554698 DOI: 10.1080/13816810.2020.1868013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Keratoconus is a progressive thinning, steepening and distortion of the cornea which can lead to loss of vision if left untreated. Keratoconus has a complex multifactorial etiology, with genetic and environmental components contributing to the disease pathophysiology. Studies have observed high concordance between monozygotic twins, discordance between dizygotic twins, and high familial segregation indicating the presence of a very strong genetic component in the pathogenesis of keratoconus. The use of genome-wide linkage studies on families and twins, genome-wide association studies (GWAS) on case-controls, next-generation sequencing (NGS)-based genomic screens on both familial and non-familial cohorts have led to the identification of keratoconus candidate genes with much greater success and increased resproducibility of genetic findings. This review focuses on candidate genes identified till date and attempts to understand their role in biological processes underlying keratoconus pathogenesis. In addition, using these genes I propose molecular pathways that could contribute to keratoconus pathogenesis. The pathways identified the presence of direct cross-talk between known candidate genes of keratoconus and remarkably, 28 known candidate genes have a direct relationship among themselves that involves direct protein-protein binding, regulatory activities such as activation and inhibition, chaperone, transcriptional activation/co-activation, and enzyme catalysis. This review attempts to describe these relationships and cross-talks in the context of keratoconus pathogenesis.
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Affiliation(s)
- Avinash M Veerappa
- Department of Ophthalmology, NYU Langone Medical Center, New York, New York, USA
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Awwad ST, Yehia M, Mehanna CJ, Fattah MA, Saad A, Hatoum A, Al-Haddad C. Tomographic and Refractive Characteristics of Pediatric First-Degree Relatives of Keratoconus Patients. Am J Ophthalmol 2019; 207:71-76. [PMID: 31194951 DOI: 10.1016/j.ajo.2019.05.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/26/2019] [Accepted: 05/31/2019] [Indexed: 11/27/2022]
Abstract
PURPOSE To evaluate the tomographic and refractive characteristics of pediatric first-degree relatives of patients with keratoconus. DESIGN Cross-sectional study. METHODS Setting: Department of Ophthalmology at the American University of Beirut Medical, Beirut, Lebanon. STUDY POPULATION Pediatric first-degree relatives of patients with keratoconus. Both eyes of all participants aged between 6 and 18 years were included and studied. EXCLUSION CRITERIA Soft contact lens use in the past 2 weeks or rigid gas-permeable lens wear within 4 weeks, history of prior ocular surgery or infectious keratitis, and unreliable corneal tomography. Masking and Randomization: Two masked cornea and refractive surgeons of different training backgrounds independently evaluated the participants' tomographic outputs. Additionally, the tomographic data were analyzed using Smadja's decision tree. OBSERVATION PROCEDURES Scheimpflug tomography, manifest refraction, and slit-lamp examination. MAIN OUTCOME MEASURES Anterior curvature indices, posterior elevation values, thinnest pachymetry, and subjective and objective tomographic interpretation. RESULTS One hundred eighty-three subjects were recruited. Tomographic evaluation after Cohen's kappa coefficient analysis revealed 32 patients as having keratoconus (17.5%), while 35 patients (19.1%) were labeled as keratoconus by objective analysis. There were 11.5%-15.5% of patients with keratoconus aged less than 11 years, 18.0% aged 12-15 years, and 25.5% aged 16-18 years. Their respective steepest anterior curvature and thinnest pachymetry are 44.8 ± 6.5 diopters (D) and 515.9 ± 39.2 μm, 47.34 ± 3.4 D and 496.1 ± 37.9 μm, and 49.7 ± 6.1 D and 486.0 ± 66.5 μm. A total of 37.5% of the keratoconus patients were unilateral as evaluated by tomography alone. CONCLUSIONS The prevalence of keratoconus in pediatric first-degree relatives of diagnosed keratoconus patients is high. Screening in this high-risk group is warranted.
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Distribution of Different Corneal Topography Patterns in Iranian Schoolchildren: The Shahroud Schoolchildren Eye Cohort Study. Eye Contact Lens 2019; 46:154-159. [PMID: 31490850 DOI: 10.1097/icl.0000000000000652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To determine the distribution of corneal topography patterns (CTPs) in children aged 6 to 12 years and its association with the central corneal thickness (CCT), axial length (AL), mean corneal power (MCP), and corneal astigmatism (CA). METHODS In this population-based study, 5,620 children selected through random stratified cluster sampling were examined. After applying the inclusion criteria, 4,655 right eyes were analyzed. The Pentacam was used to determine the CTP and measure CA and MCP, and the BioGraph was used to measure the AL. Corneal topography patterns were classified based on the 10 patterns proposed by Rabinowitz et al. RESULTS:: The most common pattern in the right eye was the oval pattern [32.7%, 95% confidence interval (CI): 30.9-34.5] followed by asymmetric bowtie with superior steepening (AB-SS) (14.5%, 95% CI: 13.3-15.7), whereas the rarest patterns were AB with skewed radial axis (AB-SRAX) (0.1%, 95% CI: 0.0-0.2) and irregular pattern (0.2%, 95% CI: 0.1-0.4). The similarity between the two eyes was 23.2% (95% CI: 20.9-25.7). The mean CCT was significantly higher in AB-SS than inferior steepening (IS) (P=0.023), symmetric bowtie with SRAX (SB-SRAX) (P=0.030), and AB with IS (AB-IS) (P=0.015). Corneal astigmatism was higher in SB-SRAX compared with round and oval patterns (P value for both <0.001). The AL was greater, and the MCP was lower in the oval versus the SB-SRAX pattern (P value for both <0.001). CONCLUSION The distribution of CTP was different in children and adults, and the oval and AB-SS patterns were the most common CTPs in the current study.
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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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Malfeito M, Regueiro U, Pérez-Mato M, Campos F, Sobrino T, Lema I. Innate Immunity Biomarkers for Early Detection of Keratoconus. Ocul Immunol Inflamm 2018; 27:942-948. [DOI: 10.1080/09273948.2018.1511813] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Mercedes Malfeito
- Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Universidade de Santiago de Compostela, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
- Facultade de Óptica E Optometría, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Uxía Regueiro
- Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Universidade de Santiago de Compostela, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
- Facultade de Óptica E Optometría, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - María Pérez-Mato
- Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Universidade de Santiago de Compostela, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - Francisco Campos
- Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Universidade de Santiago de Compostela, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - Tomás Sobrino
- Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Universidade de Santiago de Compostela, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - Isabel Lema
- Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Universidade de Santiago de Compostela, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
- Facultade de Óptica E Optometría, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
- Hospital Provincial de Conxo, Instituto Galego de Oftalmoloxía (INGO), Santiago de Compostela, Spain
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Huseynli S, Abdulaliyeva F. Evaluation of Scheimpflug Tomography Parameters in Subclinical Keratoconus, Clinical Keratoconus and Normal Caucasian Eyes. Turk J Ophthalmol 2018; 48:99-108. [PMID: 29988819 PMCID: PMC6032960 DOI: 10.4274/tjo.89587] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 11/30/2017] [Indexed: 12/01/2022] Open
Abstract
Objectives To evaluate tomographic and topographic parameters in subclinical and clinical keratoconus eyes by comparing them with normal eyes in a young Caucasian population. Materials and Methods This cross-sectional study included 88 normal eyes (control group), bilateral data from the preclinical stage of 24 progressive keratoconus eyes (bilateral subclinical keratoconus group), 40 fellow eyes of patients with unilateral keratoconus (fellow eyes group) and 97 eyes with mild keratoconus (clinical keratoconus group). Topographic and tomographic data, data from enhanced elevation maps and keratoconus indices were measured in all study eyes using Scheimpflug tomography. Receiver operating characteristic (ROC) curve analysis was used to assess individual parameters to discriminate eyes of patients with subclinical and clinical keratoconus from control eyes. The sensitivity and specificity of the main effective parameters were evaluated and optimal cut-off points were identified to differentiate subclinical keratoconus and keratoconus from normal corneas. Results Comparison of all subclinical and clinical keratoconus eyes from the normal group revealed significant differences in most diagnostic parameters. The ROC curve analysis showed high overall predictive accuracy of several Pentacam parameters (overall D value, anterior and posterior elevations and difference elevations, pachymetry progression index, index of surface variance, index of height decentration and keratoconus index) in discriminating ectatic corneas from normal ones. These outcomes were proportionally less pronounced in all subclinical keratoconus eyes than in the clinical keratoconus eyes. Pachymetric readings were progressively lower in the bilateral subclinical keratoconus eyes and sensitivity and specificity of the analyzed tomographic and topographic parameters were higher than the fellow eyes group when differentiating subclinical keratoconus from healthy corneas. Conclusion Scheimpflug tomography parameters such as D value, elevation parameters, progression index and several surface indices can effectively differentiate keratoconus from normal corneas in a Caucasian population. Nevertheless, a combination of different data is required to distinguish subclinical keratoconus.
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Affiliation(s)
- Samira Huseynli
- National Ophthalmology Center Named After Academician Zarifa Aliyeva, Ophthalmology Clinic, Baku, Azerbaijan
| | - Farah Abdulaliyeva
- National Ophthalmology Center Named After Academician Zarifa Aliyeva, Ophthalmology Clinic, Baku, Azerbaijan
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Koc M, Tekin K, Tekin MI, Uzel MM, Kosekahya P, Ozulken K, Yilmazbas P. An Early Finding of Keratoconus: Increase in Corneal Densitometry. Cornea 2018; 37:580-586. [PMID: 29384807 DOI: 10.1097/ico.0000000000001537] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate the corneal densitometry in subclinical keratoconus with normal elevation and pachymetric parameters. METHODS Patients with clinical keratoconus in one eye and subclinical keratoconus in the fellow eye were identified. The study group was selected from patients with subclinical keratoconus who showed normal results from topographic and Belin-Ambrósio Enhanced Ectasia Display III (BAD) analysis (Kmean <47.2 diopters, inferior-superior asymmetry <1.4 diopters, and KISA% <60%, elevation <5 μm, PPIaverage <1.06, PPImaximum <1.44, ARTaverage <414 μm, ARTmaximum <339 μm, and final D <1.6). The control group was selected from candidates for refractive surgery. The densitometric analyses were performed through the Pentacam HR (Oculus, Germany). RESULTS The medical records of 3474 patients with keratoconus were examined, and 116 (3.3%) subclinical keratoconus cases were detected. Normal BAD analysis results were obtained from 38 patients (1.1%). The control group also consisted of 38 patients. There were no significant differences between the eyes with subclinical keratoconus and those of the control in corrected distance visual acuity and topographic, topometric, and tomographic parameters (P > 0.05). In all layers of the 0- to 2-mm zone and in the anterior and central layers of the 0- to 6-mm zone, corneal densitometry was significantly higher in the subclinical keratoconus than the control (P < 0.001). In discriminating eyes with subclinical keratoconus from normal, the anterior layer in the 0- to 2-mm zone showed the highest area under the curve (0.883; cutoff: 19.7; sensitivity: 75%; specificity: 90%) in a receiver operating characteristic analysis. CONCLUSIONS The increase in densitometry in the central zone could be useful in detecting subclinical keratoconus.
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Affiliation(s)
- Mustafa Koc
- Ophthalmology Department, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Kemal Tekin
- Ophthalmology Department, Kars State Hospital, Kars, Turkey
| | - Merve Inanc Tekin
- Ophthalmology Department, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | | | - Pinar Kosekahya
- Ophthalmology Department, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Kemal Ozulken
- Ophthalmology Department, Dunyagoz Hospital, Ankara, Turkey
| | - Pelin Yilmazbas
- Ophthalmology Department, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
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Aksoy S, Akkaya S, Özkurt Y, Kurna S, Açıkalın B, Şengör T. Topography and Higher Order Corneal Aberrations of the Fellow Eye in Unilateral Keratoconus. Turk J Ophthalmol 2017; 47:249-254. [PMID: 29109892 PMCID: PMC5661173 DOI: 10.4274/tjo.45220] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 02/23/2017] [Indexed: 12/01/2022] Open
Abstract
Objectives Comparison of topography and corneal higher order aberrations (HOA) data of fellow normal eyes of unilateral keratoconus patients with keratoconus eyes and control group. Materials and Methods The records of 196 patients with keratoconus were reviewed. Twenty patients were identified as unilateral keratoconus. The best corrected visual acuity (BCVA), topography and aberration data of the unilateral keratoconus patients' normal eyes were compared with their contralateral keratoconus eyes and with control group eyes. For statistical analysis, flat and steep keratometry values, average corneal power, cylindrical power, surface regularity index (SRI), surface asymmetry index (SAI), inferior-superior ratio (I-S), keratoconus prediction index, and elevation-depression power (EDP) and diameter (EDD) topography indices were selected. Results Mean age of the unilateral keratoconus patients was 26.05±4.73 years and that of the control group was 23.6±8.53 years (p>0.05). There was no statistical difference in BCVA between normal and control eyes (p=0.108), whereas BCVA values were significantly lower in eyes with keratoconus (p=0.001). Comparison of quantitative topographic indices between the groups showed that all indices except the I-S ratio were significantly higher in the normal group than in the control group (p<0.05). The most obvious differences were in the SRI, SAI, EDP, and EDD values. All topographic indices were higher in the keratoconus eyes compared to the normal fellow eyes. There was no difference between normal eyes and the control group in terms of spherical aberration, while coma, trefoil, irregular astigmatism, and total HOA values were higher in the normal eyes of unilateral keratoconus patients (p<0.05). All HOA values were higher in keratoconus eyes than in the control group. Conclusion According to our study, SRI, SAI, EDP, EDD values, and HOA other than spherical aberration were higher in the clinically and topographically normal fellow eyes of unilateral keratoconus patients when compared to a control group. This finding may be due to the mild asymmetric and morphologic changes in the subclinical stage of keratoconus leading to deterioration in the indicators of corneal irregularity and elevation changes. Therefore, these eyes may be exhibiting the early form of the disease.
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Affiliation(s)
- Sibel Aksoy
- Fatih Sultan Mehmet Training and Research Hospital, Ophthalmology Clinic, İstanbul, Turkey
| | - Sezen Akkaya
- Fatih Sultan Mehmet Training and Research Hospital, Ophthalmology Clinic, İstanbul, Turkey
| | - Yelda Özkurt
- Fatih Sultan Mehmet Training and Research Hospital, Ophthalmology Clinic, İstanbul, Turkey
| | - Sevda Kurna
- Fatih Sultan Mehmet Training and Research Hospital, Ophthalmology Clinic, İstanbul, Turkey
| | - Banu Açıkalın
- Fatih Sultan Mehmet Training and Research Hospital, Ophthalmology Clinic, İstanbul, Turkey
| | - Tomris Şengör
- Bilim University Faculty of Medicine, Department of Ophthalmology, İstanbul, Turkey
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Topographic typology in a consecutive series of refractive surgery candidates. Int Ophthalmol 2017; 38:1611-1619. [PMID: 28676992 DOI: 10.1007/s10792-017-0631-2] [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: 05/05/2017] [Accepted: 06/26/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE The term 'keratoconus (KC) suspect' is used as a blanket term to refer to any deviation of virgin cornea shape toward KC features. We intend to subclassify such topographies in meaningful and informative designations. METHODS Pentacam corneal topographies of 199 consecutive refractive surgery candidates (398 eyes) are examined. Features of steepness, inferior-superior asymmetry, focal steepening, thinning, and bounded anterior or posterior elevations are observed in the quad map. Scissoring on retinoscopy, loss of best spectacle-corrected visual acuity, and iron ring deposition were looked for. Through iterative observation and refinement of classification criteria-partly taken from the literature-all eyes were designated a specific topographic diagnosis, i.e., circumventing the usage of the expression KC 'suspect'. RESULTS Topographies of 308, 48, 21, 13, 6, 1, and 1 (collectively 398 eyes) were designated: normal, 'atypical normal,' forme fruste KC, posterior KC, subclinical/mild KC, superior KC, and pseudo-KC, respectively. CONCLUSION Current imaging modalities of the cornea and our accumulated experience in refractive science allow assignment of distinctive designations for abnormal corneal shapes along the topography spectrum. We devised and used the expressions: normal, atypical normal, forme fruste (arrested-incomplete) KC, posterior KC, subclinical (active latent) KC, superior KC, and pseudo-keratoconus. Identification of 1.5% (mild) KC highlights the importance of screening for ultraviolet cross-linkage candidacy in refractive surgery referrals.
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Godefrooij DA, Mangen MJJ, Chan E, O'Brart DPS, Imhof SM, de Wit GA, Wisse RPL. Cost-Effectiveness Analysis of Corneal Collagen Crosslinking for Progressive Keratoconus. Ophthalmology 2017; 124:1485-1495. [PMID: 28532974 DOI: 10.1016/j.ophtha.2017.04.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/07/2017] [Accepted: 04/10/2017] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To evaluate the cost effectiveness of corneal collagen crosslinking (CXL) for progressive keratoconus from the healthcare payer's perspective. DESIGN A probabilistic Markov-type model using data from published clinical trials and cohort studies. PARTICIPANTS Two identical cohorts, each comprising 1000 virtual patients with progressive bilateral keratoconus, were modeled; one cohort underwent CXL and the other cohort received no intervention. METHODS Both cohorts were modeled and evaluated annually over a lifetime. Quality-adjusted life years (QALYs), total cost, disease progression, and the probability of corneal transplantation, graft failure, or both were calculated based on data from published trials and cohort studies. These outcomes were compared between the 2 cohorts. In our base scenario, the stabilizing effect of CXL was assumed to be 10 years; however, longer durations also were analyzed. One-way sensitivity analyses were performed to test the robustness of the outcomes. MAIN OUTCOME MEASURE Incremental cost-effectiveness ratio (ICER), defined as euros per QALY. RESULTS Assuming a 10-year effect of CXL, the ICER was €54 384/QALY ($59 822/QALY). When we adjusted the effect of CXL to a lifelong stabilizing effect, the ICER decreased to €10 149/QALY ($11 163/QALY). Other sensitivity and scenario analyses that had a relevant impact on ICER included the discount rate, visual acuity before CXL, and healthcare costs. CONCLUSIONS Corneal collagen crosslinking for progressive keratoconus is cost effective at a willingness-to-pay threshold of 3 times the current gross domestic product (GDP) per capita. Moreover, a longer stabilizing effect of CXL increases cost effectiveness. If CXL had a stabilizing effect on keratoconus of 15 years or longer, then the ICER would be less than the 1 × GDP per capita threshold and thus very cost effective.
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Affiliation(s)
- Daniel A Godefrooij
- Utrecht Cornea Research Group, Department of Ophthalmology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Marie-Josee J Mangen
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands; National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Elsie Chan
- Royal Victorian Eye and Ear Hospital, Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
| | - David P S O'Brart
- King's College, Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom
| | - Saskia M Imhof
- Utrecht Cornea Research Group, Department of Ophthalmology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - G Ardine de Wit
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands; National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Robert P L Wisse
- Utrecht Cornea Research Group, Department of Ophthalmology, University Medical Center Utrecht, Utrecht, The Netherlands
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Naderan M, Rajabi MT, Zarrinbakhsh P. Intereye asymmetry in bilateral keratoconus, keratoconus suspect and normal eyes and its relationship with disease severity. Br J Ophthalmol 2017; 101:1475-1482. [PMID: 28432114 DOI: 10.1136/bjophthalmol-2016-309841] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/10/2017] [Accepted: 02/28/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND/AIM To describe the intereye asymmetry in patients with keratoconus (KC), keratoconus suspect (KCS) and normal participants, and to evaluate the relationship between asymmetry and disease severity. METHODS In this prospective observational comparative study, 446 patients with bilateral KC, 68 patients with bilateral KCS and 306 normal participants underwent topographic, keratometric and pachymetric evaluations by Pentacam as well as refractive and visual acuity examinations. The intereye asymmetry in each parameter was calculated and compared between the groups. RESULTS All parameters were significantly different between the worse and better eyes in the KC group (p<0.05), but not in the KCS and normal groups. No significant differences were observed in the measurements of the worse and better eyes of the normal group (p>0.05). There was a statistically significant greater intereye asymmetry in all parameters in the KC group compared with the KCS and normal groups (p<0.05). The intraclass correlations were poor in patients with KC, moderate to good in patients suspected with KC and strong in normal participants. There were statistically significant relationships between the intereye asymmetry in all parameters and KC severity in the worse eye in which intereye asymmetry significantly increased with an increase in disease severity, based on Keratoconus Severity Score classification (p<0.05). According to receiver operating characteristic analysis, the intereye asymmetry would effectively discriminate KC and KCS from normal eyes. CONCLUSION KC is an asymmetric disease, and the degree of asymmetry is associated with disease severity. The analysis of intereye asymmetry should be performed along with unilateral evaluation in the screening of KC.
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Affiliation(s)
- Mohammad Naderan
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Taher Rajabi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Kovács I, Miháltz K, Kránitz K, Juhász É, Takács Á, Dienes L, Gergely R, Nagy ZZ. Accuracy of machine learning classifiers using bilateral data from a Scheimpflug camera for identifying eyes with preclinical signs of keratoconus. J Cataract Refract Surg 2016; 42:275-83. [PMID: 27026453 DOI: 10.1016/j.jcrs.2015.09.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/19/2015] [Accepted: 09/30/2015] [Indexed: 12/20/2022]
Abstract
PURPOSE To describe the topographic and tomographic characteristics of normal fellow eyes of unilateral keratoconus cases and to evaluate the accuracy of machine learning classifiers in discriminating healthy corneas from the normal fellow corneas. SETTING Department of Ophthalmology, Semmelweis University, Budapest, Hungary. DESIGN Retrospective case-control study. METHODS Patients with bilateral keratoconus (keratoconus group), clinically and according to the keratoconus indices of the Pentacam HR Scheimpflug camera; normal fellow eyes of patients with unilateral keratoconus (fellow-eye group); and eyes of refractive surgery candidates (control group) were compared. Tomographic data, topographic data, and keratoconus indices were measured in both eyes using the Scheimpflug camera. Receiver operating characteristic (ROC) analysis was used to assess the performance of automated classifiers trained on bilateral data as well as individual parameters to discriminate fellow eyes of patients with keratoconus from control eyes. RESULTS Keratometry, elevation, and keratoconus indices values were significantly higher and pachymetry values were significantly lower in keratoconus eyes than in fellow eyes of unilateral keratoconus cases (P < .001). These fellow eyes had significantly higher keratometry, elevation, and keratoconus index values and significantly lower pachymetry values than control eyes (P < .001). Automated classifiers trained on bilateral data of index of height decentration had higher accuracy than the unilateral single parameter in discriminating fellow eyes of patients with keratoconus from control eyes (area under ROC 0.96 versus 0.88). CONCLUSION Automatic classifiers trained on bilateral data were better than single parameters in discriminating fellow eyes of patients with unilateral keratoconus with preclinical signs of keratoconus from normal eyes. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Illés Kovács
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria.
| | - Kata Miháltz
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Kinga Kránitz
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Éva Juhász
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Ágnes Takács
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Lóránt Dienes
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Róbert Gergely
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Zoltán Z Nagy
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
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Nishtala K, Pahuja N, Shetty R, Nuijts RMMA, Ghosh A. Tear biomarkers for keratoconus. EYE AND VISION 2016; 3:19. [PMID: 27493978 PMCID: PMC4973115 DOI: 10.1186/s40662-016-0051-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 07/19/2016] [Indexed: 12/21/2022]
Abstract
Keratoconus is a progressive corneal thinning, ectatic condition, which affects vision. Recent advances in corneal topography measurements has helped advance proper diagnosis of this condition and increased research and clinical interests in the disease etiopathogenesis. Considerable progress has been achieved in understanding the progression of the disease and tear fluid has played a major role in the progress. This review discusses the importance of tear fluid as a source of biomarker for keratoconus and how advances in technology have helped map the complexity of tears and thereby molecular readouts of the disease. Expanding knowledge of the tear proteome, lipidome and metabolome opened up new avenues to study keratoconus and to identify probable prognostic or diagnostic biomarkers for the disease. A multidimensional approach of analyzing tear fluid of patients layering on proteomics, lipidomics and metabolomics is necessary in effectively decoding keratoconus and thereby identifying targets for its treatment.
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Affiliation(s)
| | - Natasha Pahuja
- Cornea Department, Narayana Nethralaya, Bangalore, India
| | - Rohit Shetty
- Cornea Department, Narayana Nethralaya, Bangalore, India
| | - Rudy M M A Nuijts
- Cornea Clinic, Department of Ophthalmology, Maastricht University Medical Center, Maastricht, Netherlands
| | - Arkasubhra Ghosh
- GROW Research Laboratory, Narayana Nethralaya Foundation, Bangalore, India
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National survey of pellucid marginal corneal degeneration in Japan. Jpn J Ophthalmol 2016; 60:341-8. [DOI: 10.1007/s10384-016-0462-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 05/11/2016] [Indexed: 11/25/2022]
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Reinstein DZ, Archer TJ, Urs R, Gobbe M, RoyChoudhury A, Silverman RH. Detection of Keratoconus in Clinically and Algorithmically Topographically Normal Fellow Eyes Using Epithelial Thickness Analysis. J Refract Surg 2016; 31:736-44. [PMID: 26544561 DOI: 10.3928/1081597x-20151021-02] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 08/11/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the effectiveness of a keratoconus-detection algorithm derived from Artemis very high-frequency (VHF) digital ultrasound (ArcScan Inc., Morrison, CO) epithelial thickness maps in the fellow eye from a series of patients with unilateral keratoconus. METHODS The study included 10 patients with moderate to advanced keratoconus in one eye but a clinically and algorithmically topographically normal fellow eye. VHF digital ultrasound epithelial thickness data were acquired and a previously developed classification model was applied for identification of keratoconus to the clinically normal fellow eyes. Pentacam (Oculus Optikgeräte, Wetzlar, Germany) Belin-Ambrósio Enhanced Ectasia Display "D" score (BAD-D) data (5 of 10 eyes), and Orbscan (Bausch & Lomb, Rochester, NY) SCORE data (9 of 10 eyes) were also evaluated. RESULTS Five of the 10 fellow eyes were classified as keratoconic by the VHF digital ultrasound epithelium model. Five of 9 fellow eyes were classified as keratoconic by the SCORE model. For the 5 fellow eyes with Pentacam and VHF digital ultrasound data, one was classified as keratoconic by the VHF digital ultrasound model, one (different) eye by a combined VHF digital ultrasound and Pentacam model, and none by BAD-D alone. CONCLUSIONS Under the assumption that keratoconus is a bilateral but asymmetric disease, half of the 'normal' fellow eyes could be found to have keratoconus using epithelial thickness maps. The Orbscan SCORE or the combination of topographic BAD-D criteria with epithelial maps did not perform better.
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Tummanapalli SS, Potluri H, Vaddavalli PK, Sangwan VS. Efficacy of axial and tangential corneal topography maps in detecting subclinical keratoconus. J Cataract Refract Surg 2015; 41:2205-14. [DOI: 10.1016/j.jcrs.2015.10.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 04/09/2015] [Accepted: 04/18/2015] [Indexed: 10/22/2022]
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The genetic and environmental factors for keratoconus. BIOMED RESEARCH INTERNATIONAL 2015; 2015:795738. [PMID: 26075261 PMCID: PMC4449900 DOI: 10.1155/2015/795738] [Citation(s) in RCA: 233] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 12/22/2022]
Abstract
Keratoconus (KC) is the most common cornea ectatic disorder. It is characterized by a cone-shaped thin cornea leading to myopia, irregular astigmatism, and vision impairment. It affects all ethnic groups and both genders. Both environmental and genetic factors may contribute to its pathogenesis. This review is to summarize the current research development in KC epidemiology and genetic etiology. Environmental factors include but are not limited to eye rubbing, atopy, sun exposure, and geography. Genetic discoveries have been reviewed with evidence from family-based linkage analysis and fine mapping in linkage region, genome-wide association studies, and candidate genes analyses. A number of genes have been discovered at a relatively rapid pace. The detailed molecular mechanism underlying KC pathogenesis will significantly advance our understanding of KC and promote the development of potential therapies.
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Munsamy AJ, Moodley VR, Naidoo P, Mangwarara TR, Abdullah R, Govender D, Dlamini P. A frequency analysis of cone characteristics for the different stages of keratoconus. AFRICAN VISION AND EYE HEALTH 2015. [DOI: 10.4102/aveh.v74i1.302] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Background: The stages of keratoconus can be classified according to the degree of corneal conicity as either early or advanced, or morphologically by the shape of the cone. Knowledge of the different cone characteristics for the different stages of keratoconus may assist practitioners in diagnosing and managing these patients.Aim: To describe the cone characteristics for the different stages of keratoconus.Methods: In this retrospective study, a sample of 190 eyes from 106 cases of previously diagnosed keratoconic patients was analysed. The stage of keratoconus and cone characteristics, namely: cone location, cone decentration, morphology, and topographical patterns were analysed using an Oculus 3M corneal topographer.Results: Our study revealed that for all stages of keratoconus centrally located cones were the most frequent, with corneal apical decentration between 0 mm and 2 mm. Frequency analysis revealed that nipple cones were most frequent in all stages. Topographical pattern frequencies revealed a wide distribution amongst the different corneal patterns in all stages of keratoconus.Conclusion: Cone analysis should be of consideration to the contact lens practitioner when deciding on management of the condition. It additionally serves to compliment the clinical signs such as nerve visibility, Fleischer’s ring, Vogt’s striae and corneal scarring.
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Galletti JD, Ruiseñor Vázquez PR, Minguez N, Delrivo M, Bonthoux FF, Pförtner T, Galletti JG. Corneal Asymmetry Analysis by Pentacam Scheimpflug Tomography for Keratoconus Diagnosis. J Refract Surg 2015; 31:116-23. [DOI: 10.3928/1081597x-20150122-07] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 11/19/2014] [Indexed: 11/20/2022]
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Evaluation of intereye corneal asymmetry in patients with keratoconus. A scheimpflug imaging study. PLoS One 2014; 9:e108882. [PMID: 25296183 PMCID: PMC4189959 DOI: 10.1371/journal.pone.0108882] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 08/26/2014] [Indexed: 11/19/2022] Open
Abstract
Purpose To assess the correlation between keratoconus severity and intereye asymmetry of pachymetric data and posterior elevation values and to evaluate their combined accuracy in discriminating normal corneas from those with keratoconus. Methods This study included 97 patients: 65 subjects with bilateral normal corneas (NC) and 32 with keratoconus (KC). Central corneal thickness (CCT), thinnest corneal thickness (ThCT) and posterior elevation (PE) at the thinnest point of the cornea were measured in both eyes using Scheimpflug imaging. Intereye asymmetry and its correlation with keratoconus severity were calculated for each variable. The area under the receiver operating characteristic curve (AUROC) was used to compare predictive accuracy of different variables for keratoconus. Results In normal eyes, intereye differences were significantly lower compared with the keratoconus eyes (p<0.001, for CCT, ThCT and PE). There was a significant exponential correlation between disease severity and intereye asymmetry of steep keratometry (r2 = 0.55, p<0.001), CCT (r2 = 0.39, p<0.001), ThCT (r2 = 0.48, p<0.001) and PE (r2 = 0.64, p<0.001). After adjustment for keratoconus severity, asymmetry in thinnest pachymetry proved to be the best parameter to characterize intereye corneal asymmetry in keratoconus. This variable had high accuracy and significantly better discriminating ability (AUROC: 0.99) for KC than posterior elevation (AUROC: 0.96), ThCT (AUROC: 0.94) or CCT (AUROC: 0.92) alone. Conclusions There is an increased intereye asymmetry in keratometry, pachymetry and posterior corneal elevation values in keratoconic patients compared to subjects with normal corneas. Keratoconus patients with more severe disease are also more asymmetric in their disease status which should be taken into account during clinical care.
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Reddy JC, Rapuano CJ, Cater JR, Suri K, Nagra PK, Hammersmith KM. Comparative evaluation of dual Scheimpflug imaging parameters in keratoconus, early keratoconus, and normal eyes. J Cataract Refract Surg 2014; 40:582-92. [PMID: 24680519 DOI: 10.1016/j.jcrs.2013.08.061] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 08/27/2013] [Accepted: 08/27/2013] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine the efficacy of various parameters measured by dual Scheimpflug imaging technology in differentiating eyes with keratoconus or early keratoconus from normal eyes. SETTING Cornea Service, Wills Eye Institute, Philadelphia, Pennsylvania, USA. DESIGN Comparative case series. METHODS A retrospective evaluation was performed of the parameters provided by the Galilei dual Scheimpflug analyzer in keratoconus, early keratoconus, and normal eyes. Logistic regression and receiver operating characteristic curve analysis were used to compare the mean values and to calculate the sensitivity and specificity of these parameters. RESULTS Many parameters were statistically significantly different between keratoconus and normal eyes compared with early keratoconus eyes (P<.05). Total cornea power-steep and posterior curvature-steep keratometry had the highest area under the curve (AUC) score (0.99) for differentiating keratoconus eyes from normal eyes. All anterior curvature parameters were statistically significant in differentiating keratoconus eyes from normal eyes, whereas only the anterior curvature-steep was statistically significant in differentiating early keratoconus eyes from normal eyes. The central pachymetry and thinnest pachymetry were statistically significant in differentiating keratoconus and early keratoconus eyes from normal eyes. Third-order root mean square (RMS) and total RMS had the highest AUC scores (0.83 and 0.82, respectively) for differentiating early keratoconus eyes from normal eyes. CONCLUSION Total corneal power, anterior curvature, posterior curvature, pachymetry, and corneal aberration data generated from the dual Scheimpflug analyzer showed promising results in differentiating keratoconus and early keratoconus eyes from normal eyes. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Jagadesh C Reddy
- From the Cornea Service (Reddy, Rapuano, Cater, Suri, Nagra, Hammersmith), Wills Eye Institute, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Cornea, Anterior Segment and Refractive Surgery Services (Reddy), LV Prasad Eyes Institute, Kallam Anji Reddy Campus, Hyderabad, India
| | - Christopher J Rapuano
- From the Cornea Service (Reddy, Rapuano, Cater, Suri, Nagra, Hammersmith), Wills Eye Institute, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Cornea, Anterior Segment and Refractive Surgery Services (Reddy), LV Prasad Eyes Institute, Kallam Anji Reddy Campus, Hyderabad, India.
| | - Jacqueline R Cater
- From the Cornea Service (Reddy, Rapuano, Cater, Suri, Nagra, Hammersmith), Wills Eye Institute, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Cornea, Anterior Segment and Refractive Surgery Services (Reddy), LV Prasad Eyes Institute, Kallam Anji Reddy Campus, Hyderabad, India
| | - Kunal Suri
- From the Cornea Service (Reddy, Rapuano, Cater, Suri, Nagra, Hammersmith), Wills Eye Institute, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Cornea, Anterior Segment and Refractive Surgery Services (Reddy), LV Prasad Eyes Institute, Kallam Anji Reddy Campus, Hyderabad, India
| | - Parveen K Nagra
- From the Cornea Service (Reddy, Rapuano, Cater, Suri, Nagra, Hammersmith), Wills Eye Institute, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Cornea, Anterior Segment and Refractive Surgery Services (Reddy), LV Prasad Eyes Institute, Kallam Anji Reddy Campus, Hyderabad, India
| | - Kristin M Hammersmith
- From the Cornea Service (Reddy, Rapuano, Cater, Suri, Nagra, Hammersmith), Wills Eye Institute, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Cornea, Anterior Segment and Refractive Surgery Services (Reddy), LV Prasad Eyes Institute, Kallam Anji Reddy Campus, Hyderabad, India
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Abu Ameerh MA, Bussières N, Hamad GI, Al Bdour MD. Topographic characteristics of keratoconus among a sample of Jordanian patients. Int J Ophthalmol 2014; 7:714-9. [PMID: 25161949 DOI: 10.3980/j.issn.2222-3959.2014.04.24] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 01/16/2014] [Indexed: 11/02/2022] Open
Abstract
AIM To identify topographic characteristics of keratoconus in a Jordanian sample. METHODS This study characterized 210 corneas affected with keratoconus presenting to Jordan University Hospital. Patients were diagnosed based on clinical examinations and Pentacam imaging. Eyes of males (n=101) were of a similar proportion to females (n=109). All of the 111 patients were affected bilaterally. Ages ranged between 13 and 44y with a mean age of 25.2y. RESULTS Results revealed significant differences between males and females at the level of the flat curvature power, basement membrane thickness and size of the anterior chamber. Eyes were arranged in three groups based on severity levels: mild, moderate and severe determined by the mean curvature power (Km). Results show that the flat (K1) and steep (K2) curvature powers, corneal asphericity coefficient (QV), thinnest point, pachy apex and basement membrane thickness are significantly different among the three groups, but not the corneal and anterior chamber volumes. Morphological analyses, based on sagittal maps, show no differences in keratometric values between eyes with different sagittal patterns except for the vertical location of the pachy apex relative to the pupil center and the thinnest point. Eyes with the island front elevation map are significantly more affected than eyes with the U shape and the ridge pattern. CONCLUSION All keratometric values measured except for corneal and anterior chamber volumes vary significantly with disease severity. The vertical pachy apex location correlates well with severity levels while the horizontal location seems to have no effect. Our study also indicates that front elevation maps may be a better predictor of the severity of keratoconus than sagittal maps.
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Affiliation(s)
| | - Nathalie Bussières
- Faculty of Applied Medical Sciences, German Jordanian University, Amman 11180, Jordan
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Corneal topographic and tomographic analysis of fellow eyes in unilateral keratoconus patients using Pentacam. Am J Ophthalmol 2014; 157:103-109.e1. [PMID: 24452012 DOI: 10.1016/j.ajo.2013.08.014] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 08/13/2013] [Accepted: 08/13/2013] [Indexed: 11/23/2022]
Abstract
PURPOSE To evaluate topographic and tomographic changes in fellow eyes in unilateral keratoconus (KCN) patients by comparing them with normal eyes. DESIGN Retrospective comparative case series. METHODS Fourteen eyes of 14 patients with unilateral KCN and 34 eyes of 34 refractive surgery candidates were divided into 3 diagnostic groups using a Pentacam rotating Scheimpflug camera: advanced KCN eyes of unilateral KCN (KCN group, 14 eyes), normal fellow eyes of unilateral KCN (fellow eye group, 14 eyes), and refractive surgery candidates (normal group, 34 eyes). Topographic and tomographic parameters, which were obtained from Pentacam using sagittal curvature, elevation, and corneal thickness maps, were compared among the 3 groups. Receiver operating characteristic (ROC) curves were used to identify cutoff points in discriminating between fellow and normal eyes. RESULTS Keratometric asymmetry, topometric indices, and elevation differences (maximum - minimum) on both the anterior and posterior surfaces were statistically different (P < .05). On ROC curve analysis, keratometric asymmetry and topometric index were best at discriminating fellow eyes from normal, followed by elevation differences (maximum - minimum) on the posterior and anterior cornea surface. CONCLUSIONS Fellow eyes in unilateral KCN showed differences in several parameters that were not detectable with the Pentacam detection program, when compared with normal. However, each single parameter alone is not sufficient to detect early changes; thus, elevation indices as well as indices of anterior curvature should be considered together.
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Intereye Asymmetry Detected by Scheimpflug Imaging in Subjects With Normal Corneas and Keratoconus. Cornea 2013; 32:779-82. [DOI: 10.1097/ico.0b013e31827b14ae] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Saad A, Gatinel D. Association of Corneal Indices for the Detection of Ectasia-susceptible Corneas. J Refract Surg 2012; 28:166; author reply 166-7. [DOI: 10.3928/1081597x-20120214-01] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
ABSTRACT
Undetected subclinical keratoconus (KC) is the main risk factor for iatrogenic ectasia. Many parameters have been proposed to help differentiate normal from subclinical KC corneas. Linear discriminant analysis is a technique that models the difference between different classes of data by looking for linear combinations of variables which best explain the data. The association of surfaces elevation, corneal thickness profile and anterior curvature indices leads to the best sensitivity and specificity for the discrimination between normal and early subclinical KC corneas.
How to cite this article
Gatinel D, Saad A. The Challenges of the Detection of Subclinical Keratoconus at Its Earliest Stage. Int J Keratoco Ectatic Corneal Dis 2012;1(1):36-43.
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Randleman JB. The expanding spectrum of refractive surgery. J Refract Surg 2011; 27:707. [PMID: 21986001 DOI: 10.3928/1081597x-20110920-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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