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Lee SSY, Diaz-Torres S, He W, Yazar S, Chan E, Chong EW, Gharahkhani P, Macgregor S, Lingham G, Mackey DA. Polygenic Prediction of Keratoconus and its Measures: Cross-Sectional and Longitudinal Analyses in Community-Based Young Adults. Am J Ophthalmol 2024; 265:248-256. [PMID: 38740237 DOI: 10.1016/j.ajo.2024.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 04/28/2024] [Accepted: 05/07/2024] [Indexed: 05/16/2024]
Abstract
PURPOSE This study evaluates the performance of a multitrait polygenic risk score (PRS) in an independent cohort to predict incident or progression of keratoconus. DESIGN Prospective cross-sectional and cohort study METHODS: Setting: Single-center; Study population: 1478 community-based young adults (18-30 years; 51% female), including 609 (52% female) who returned for an 8-year follow-up; Observation procedures: Scheimpflug imaging (Pentacam, Oculus), genotyping and development of a multitrait PRS previously validated to predict keratoconus in older adults.; Main outcome measure: Belin/Ambrόsio enhanced ectasia display (BAD-D) score and keratoconus, defined as BAD-D ≥2.6, were each analyzed against the PRS using linear and logistic regression, respectively. RESULTS Prevalence of keratoconus was 2.5% (95% confidence interval [CI] = 1.9-3.6) in the cross-sectional cohort. Each z-score increase in PRS was associated with worse BAD-D z-score by 0.13 (95%CI = 0.08-0.18) and 1.6 increased odds of keratoconus. The 8-year keratoconus incidence was 2.6% (95%CI = 1.3-4.0). Participants in the highest PRS decile were more likely to have incident keratoconus compared to the rest of the cohort (odds ratio = 3.85, 95%CI = 1.21-12.22). For each z-score increase in PRS, 8-year change in BAD-D z-score worsened by 0.11 (95%CI = 0.04-0.17). CONCLUSIONS A PRS for keratoconus could be useful in predicting incident keratoconus and progression, demonstrating its potential utility in clinical settings to identify patients at high risk of postsurgery ectasia or those who may benefit most from keratoconus intervention.
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Affiliation(s)
- Samantha Sze-Yee Lee
- From the University of Western Australia (S.S.Y.L., S.Y., G.L., D.A.M.), Centre for Ophthalmology and Visual Science (Incorporating the Lions Eye Institute), Perth, WA, Australia.
| | - Santiago Diaz-Torres
- QIMR Berghofer Medical Research Institute (S.D.T., W.H., P.G., S.M.), Brisbane, QLD, Australia; Faculty of Medicine (S.D.T., W.H., P.G., S.M.), University of Queensland, Brisbane, QLD, Australia
| | - Weixiong He
- QIMR Berghofer Medical Research Institute (S.D.T., W.H., P.G., S.M.), Brisbane, QLD, Australia; Faculty of Medicine (S.D.T., W.H., P.G., S.M.), University of Queensland, Brisbane, QLD, Australia
| | - Seyhan Yazar
- From the University of Western Australia (S.S.Y.L., S.Y., G.L., D.A.M.), Centre for Ophthalmology and Visual Science (Incorporating the Lions Eye Institute), Perth, WA, Australia; Single Cell and Computational Genomics Laboratory (S.Y.), Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
| | - Elsie Chan
- Centre for Eye Research Australia (E.C., E.W.C., D.A.M.), University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Elaine W Chong
- Centre for Eye Research Australia (E.C., E.W.C., D.A.M.), University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia; Royal Melbourne Hospital (E.W.C.), Melbourne, VIC, Australia
| | - Puya Gharahkhani
- QIMR Berghofer Medical Research Institute (S.D.T., W.H., P.G., S.M.), Brisbane, QLD, Australia; Faculty of Medicine (S.D.T., W.H., P.G., S.M.), University of Queensland, Brisbane, QLD, Australia; School of Biomedical Sciences (P.G.), Queensland University of Technology, Brisbane, QLD, Australia
| | - Stuart Macgregor
- QIMR Berghofer Medical Research Institute (S.D.T., W.H., P.G., S.M.), Brisbane, QLD, Australia; Faculty of Medicine (S.D.T., W.H., P.G., S.M.), University of Queensland, Brisbane, QLD, Australia
| | - Gareth Lingham
- From the University of Western Australia (S.S.Y.L., S.Y., G.L., D.A.M.), Centre for Ophthalmology and Visual Science (Incorporating the Lions Eye Institute), Perth, WA, Australia; Centre for Eye Research Ireland (G.L.), Environmental, Sustainability and Health Institute, Technological University Dublin, Dublin, Ireland
| | - David A Mackey
- From the University of Western Australia (S.S.Y.L., S.Y., G.L., D.A.M.), Centre for Ophthalmology and Visual Science (Incorporating the Lions Eye Institute), Perth, WA, Australia; Centre for Eye Research Australia (E.C., E.W.C., D.A.M.), University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia; School of Medicine, Menzies Research Institute Tasmania (D.A.M.), University of Tasmania, Hobart, TAS, Australia
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Zhang X, Wang Q, Cui F, Wu X, Zhang C. Mendelian randomization analysis does not reveal a causal influence between keratoconus and three major mental disorders. Front Psychiatry 2024; 15:1370670. [PMID: 39234617 PMCID: PMC11371735 DOI: 10.3389/fpsyt.2024.1370670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 08/05/2024] [Indexed: 09/06/2024] Open
Abstract
Background Observational studies have suggested at a possible link between keratoconus (KC) and various mental disorders, but the exact direction of causation in these associations remains unclear. This study aims to investigate the potential causal link between KC and three prominent mental conditions: Anxiety, Depression, and Schizophrenia. Methods Using instrumental variables identified from Genome-wide association study (GWAS) data of European individuals, we conducted bidirectional two-sample Mendelian Randomization (MR) analyses to explore potential causal relationships between KC and the three major mental disorders. We primarily employed the Inverse-Variance Weighted (IVW) method to evaluate causality. In addition, we performed four supplementary MR methods (MR-Egger, Weighted Median, Simple Mode, and Weighted Mode). Furthermore, we conducted various sensitivity analyses to assess heterogeneity, horizontal pleiotropy, and result stability. Results Our findings did not reveal any concrete evidence of a causal link between KC and the three major mental disorders, namely anxiety, depression, and schizophrenia [anxiety: odds ratio (OR)=0.997, 95% confidence interval (CI)=0.988-1.008, p = 0.621; depression: OR=1.008, 95% CI=0.999-1.017, p = 0.084; schizophrenia: OR=1.002, 95% CI= 0.984-1.020, p = 0.840]. Similarly, the three major mental disorders were not caustically associated with KC [anxiety: OR=1.014, 95% CI=0.635-1.620, p = 0.953; depression: OR=1.109, 95% CI= 0.749-1.643, p = 0.604; schizophrenia: OR= 0.969, 95% CI= 0.884-1.062, p = 0.497]. The sensitivity analyses indicated that the results remained robust, with no signs of pleiotropy or heterogeneity. Conclusions Our study does not support a genetically determined significant causal connection between KC and the three major mental disorders. The increased occurrence of mental disorders observed in KC patients in observational reports likely arises from factors that can be modified. Further research is warranted to unveil the underlying mechanisms behind the associations observed in observational studies.
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Affiliation(s)
- Xueyan Zhang
- Department of Ophthalmology, The Jinan Second People's Hospital, Jinan, Shandong, China
| | - Qiaoling Wang
- Department of Ophthalmology, The Jinan Second People's Hospital, Jinan, Shandong, China
| | - Fenghua Cui
- Department of Ophthalmology, The Jinan Second People's Hospital, Jinan, Shandong, China
| | - Xuelian Wu
- Department of Ophthalmology, The Jinan Second People's Hospital, Jinan, Shandong, China
| | - Chenming Zhang
- Department of Ophthalmology, The Jinan Second People's Hospital, Jinan, Shandong, China
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Ben-Shaul O, Segal A, Schwartz S, Stein N, Hyams M, Saliba W, Mimouni M. Factors associated with keratoconus in Israel-A cross-sectional population-based study. Acta Ophthalmol 2024. [PMID: 38742987 DOI: 10.1111/aos.16706] [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: 06/08/2023] [Accepted: 04/11/2024] [Indexed: 05/16/2024]
Abstract
PURPOSE To identify potential factors associated with keratoconus. METHODS This cross-sectional study included data from Israel's largest healthcare provider for the years 2005-2020. Keratoconus patients and age-matched controls were identified. Demographic factors and comorbid conditions, including smoking, diabetes mellitus, asthma, myalgia, mental retardation, Down syndrome, atopic dermatitis and allergy/allergic rhinitis, were compared between the two cohorts. The independent risk factors associated with keratoconus were determined using a multivariable conditional logistic regression model. RESULTS Overall, 145 508 subjects were reviewed of which 13 228 were keratoconus patients. A ten-fold group (n = 132 280) of age-matched control subjects served as controls for comparisons. In multivariable analysis, several factors were found to be significantly associated with keratoconus. Male gender (OR = 1.27, p < 0.001), Arab ethnicity (OR = 1.50, p < 0.001), diabetes (OR = 1.19, p < 0.001), asthma (OR = 1.50, p < 0.001), myalgia (OR = 1.09, p = 0.02), mental retardation (OR = 2.63, p < 0.001), atopic dermatitis (OR = 1.35, p < 0.001) and allergic rhinitis (OR = 1.21, p < 0.001) were significantly associated with keratoconus. Smoking was significantly protective of keratoconus (OR = 0.66, p < 0.001). CONCLUSIONS This population-based study reports male gender, Arab ethnicity, diabetes, asthma, myalgia, mental retardation/Down syndrome, atopic dermatitis and allergic rhinitis as factors associated with keratoconus while smoking demonstrates a protective effect. The results of this study could guide enhanced screening strategies and early interventions, particularly for high-risk groups.
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Affiliation(s)
- Or Ben-Shaul
- Department of Ophthalmology, Lady Davis Carmel Medical Center, Haifa, Israel
- Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Adi Segal
- Department of Ophthalmology, Lady Davis Carmel Medical Center, Haifa, Israel
| | - Sharon Schwartz
- Department of Ophthalmology, Lady Davis Carmel Medical Center, Haifa, Israel
| | - Nili Stein
- Department of Community Medicine and Epidemiology, Lady Davis Carmel Medical Center, Haifa, Israel
| | - Michael Hyams
- Department of Ophthalmology, Lady Davis Carmel Medical Center, Haifa, Israel
| | - Walid Saliba
- Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
- Department of Community Medicine and Epidemiology, Lady Davis Carmel Medical Center, Haifa, Israel
| | - Michael Mimouni
- Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
- Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel
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Shetty R, Mahendran K, Joshi PD, Jeyabalan N, Jayadev C, Das D. Corneal stromal regeneration-keratoconus cell therapy: a review. Graefes Arch Clin Exp Ophthalmol 2023; 261:3051-3065. [PMID: 37074409 DOI: 10.1007/s00417-023-06064-7] [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: 01/05/2023] [Revised: 03/28/2023] [Accepted: 04/05/2023] [Indexed: 04/20/2023] Open
Abstract
BACKGROUND Keratoconus is a corneal ectatic disease caused by stromal thinning leading to astigmatism and progressive loss of vision. Loss of the keratocytes and excessive degradation of collagen fibres by matrix metalloproteinases are the molecular signatures of the disease. Despite several limitations, corneal collagen cross-linking and keratoplasty are the most widely used treatment options for keratoconus. In the pursuit of alternative treatment modalities, clinician scientists have explored cell therapy paradigms for treating the condition. METHODS Articles pertaining to keratoconus cell therapy with relevant key words were used to search in PubMed, Researchgate, and Google Scholar. The articles were selected based on their relevance, reliability, publication year, published journal, and accessibility. RESULTS Various cellular abnormalities have been reported in keratoconus. Diverse cell types such as mesenchymal stromal cells, dental pulp cells, bone marrow stem cells, haematopoietic stem cells, adipose-derived stem cells apart from embryonic and induced pluripotent stem cells can be used for keratoconus cell therapy. The results obtained show that there is a potential for these cells from various sources as a viable treatment option. CONCLUSION There is a need for consensus with respect to the source of cells, mode of delivery, stage of disease, and duration of follow-up, to establish a standard operating protocol. This would eventually widen the cell therapy options for corneal ectatic diseases beyond keratoconus.
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Affiliation(s)
- Rohit Shetty
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bangalore, India
| | - Krithikaa Mahendran
- Stem Cell Research Lab, GROW Lab, Narayana Nethralaya Foundation, Narayana Nethralaya, Bangalore, India
| | - Parth D Joshi
- Stem Cell Research Lab, GROW Lab, Narayana Nethralaya Foundation, Narayana Nethralaya, Bangalore, India
| | | | - Chaitra Jayadev
- Department of Vitreo-Retina, Narayana Nethralaya Eye Hospital, Bangalore, India
| | - Debashish Das
- Stem Cell Research Lab, GROW Lab, Narayana Nethralaya Foundation, Narayana Nethralaya, Bangalore, India.
- Stem Cell Lab, GROW Lab, Narayana Nethralaya Foundation, Narayana Nethralaya Eye Hospital, Narayana Health City, 258/A Bommasandra Industrial Area, Bangalore, 560099, Karnataka, India.
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Sahebjada S, Chan E, Sutton G, Pang CPC, Kerdraon Y, Natarajan S, Meteoukki W, Ang A, Daniell M, Baird PN. Keratoconus International Consortium (KIC)- advancing keratoconus research. BMC Ophthalmol 2023; 23:337. [PMID: 37501133 PMCID: PMC10375634 DOI: 10.1186/s12886-023-03087-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 07/16/2023] [Indexed: 07/29/2023] Open
Abstract
CLINICAL RELEVANCE The Keratoconus International Consortium (KIC) will allow better understanding of keratoconus. BACKGROUND Keratoconus is a disorder characterised by corneal elevation and thinning, leading to reduced vision. The current gaps in understanding of this disease will be discussed and the need for a multi-pronged and multi-centre engagement to enhance our understanding of keratoconus will be highlighted. DESIGN KIC has been established to address the gaps in our understanding of keratoconus with the aim of collecting baseline as well as longitudinal data on several fields. PARTICIPANTS Keratoconus and control (no corneal condition) subjects from different sites globally will be recruited in the study. METHODS KIC collects data using an online, secure database, which enables standardised data collection at member sites. Data fields collected include medical history, clinical features, quality of life and economic burden questionnaires and possible genetic sample collection from patients of different ethnicities across different geographical locations. RESULTS There are currently 40 Australian and international clinics or hospital departments who have joined the KIC. Baseline data has so far been collected on 1130 keratoconus patients and indicates a median age of 29.70 years with 61% being male. A total of 15.3% report a positive family history of keratoconus and 57.7% self-report a history of frequent eye rubbing. CONCLUSION The strength of this consortium is its international, collaborative design and use of a common data collection tool. Inclusion and analyses of cross-sectional and longitudinal data will help answer many questions that remain in keratoconus, including factors affecting progression and treatment outcomes.
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Affiliation(s)
- Srujana Sahebjada
- Centre for Eye Research Australia, Level 7, 32 Gisborne St, East Melbourne, Victoria, 3002, Australia.
- Department of Surgery, Ophthalmology, The University of Melbourne, Melbourne, Australia.
| | - Elsie Chan
- Centre for Eye Research Australia, Level 7, 32 Gisborne St, East Melbourne, Victoria, 3002, Australia
- Department of Surgery, Ophthalmology, The University of Melbourne, Melbourne, Australia
- Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Gerard Sutton
- Sydney Medical School, The University of Sydney, Sydney, Australia
- NSW Tissue Banks, Sydney, Australia
| | | | - Yves Kerdraon
- Sydney Medical School, The University of Sydney, Sydney, Australia
- Envision Eye Centre, Sydney, Australia
| | | | - Wafaa Meteoukki
- Molecular and Cellular Genetics Laboratory, Oran University of Science and Technology - Mohamed Boudiaf (USTOMB), Oran, Algeria
| | | | - Mark Daniell
- Centre for Eye Research Australia, Level 7, 32 Gisborne St, East Melbourne, Victoria, 3002, Australia
- Department of Surgery, Ophthalmology, The University of Melbourne, Melbourne, Australia
- Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Paul N Baird
- Department of Surgery, Ophthalmology, The University of Melbourne, Melbourne, Australia
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Unni P, Lee HJ. Systemic Associations with Keratoconus. Life (Basel) 2023; 13:1363. [PMID: 37374145 DOI: 10.3390/life13061363] [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: 05/06/2023] [Revised: 06/04/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Keratoconus is a disease of the cornea that results in progressive steepening and thinning of the cornea and subsequent vision loss. It nearly always presents as a bilateral disease, suggesting that there is an underlying abnormality of the corneas that becomes manifest with time. However, the mechanisms underlying the development of keratoconus are largely unknown. Associations reported between keratoconus and systemic diseases are abundant in the literature, and the list of possible associations is very long. We found that atopy, Down syndrome, and various connective tissue diseases were the most frequently cited associations in our broad literature search. Additionally, Diabetes Mellitus has been increasingly studied as a possible protective factor against keratoconus. In this review, we have summarized the evidence for and against these particular systemic conditions and keratoconus and have discussed some of the implications of keratoconus patients having these conditions.
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Affiliation(s)
- Prasida Unni
- Chobanian and Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Hyunjoo Jean Lee
- Chobanian and Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
- Department of Ophthalmology, Boston Medical Center, Boston, MA 02118, USA
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Wagner FM, Sekundo W. Iatrogenic Keratectasia after Refractive Surgery - Causes, Prophylaxis, Therapy. Klin Monbl Augenheilkd 2023; 240:783-794. [PMID: 37348513 DOI: 10.1055/a-2073-8478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
Iatrogenic keratectasia is induced thinning and protrusion of the cornea after laser refractive surgery. Known risk factors include an excessively thin postoperative residual stromal bed, a thicker flap, or preoperatively undetected evidence of preexisting subclinical keratoconus. The rate of post-refractive ectasia in eyes without identifiable preoperative risk factors is 20 per 100 000 eyes for photorefractive keratectomy, 90 per 100 000 eyes for laser in situ keratomileusis, and 11 per 100 000 eyes for small incision lenticule extraction. Traditional screening tools for preoperative risk include the ectasia risk score system and percentage of tissue alteration. More recent methods include corneal elastography and epithelial mapping, in addition to Artificial Intelligence methods for data analysis. Therapy includes contact lenses, cross-linking, implantation of intracorneal ring segments, penetrating or lamellar keratoplasty, and, in early studies, implantation of corneal lenticules.
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Affiliation(s)
- Felix Mathias Wagner
- Universitätsaugenklinik Mainz, Mainz, Deutschland
- Universitätsaugenklinik Marburg, Marburg, Deutschland
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Mazharian A, Flamant R, Elahi S, Panthier C, Rampat R, Gatinel D. Medium to long term follow up study of the efficacy of cessation of eye-rubbing to halt progression of keratoconus. Front Med (Lausanne) 2023; 10:1152266. [PMID: 37293301 PMCID: PMC10244573 DOI: 10.3389/fmed.2023.1152266] [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: 01/27/2023] [Accepted: 04/28/2023] [Indexed: 06/10/2023] Open
Abstract
Purpose To study the progression of keratoconus after cessation of eye rubbing with a minimum follow up of three-years. Design Retrospective, monocentric, longitudinal cohort study of keratoconus patients with a minimum of 3 years follow-up. Participants One hundred fifty three eyes of seventy-seven consecutive patients with keratoconus were included. Methods Initial examination consisted of anterior and posterior segment evaluation using slit-lamp biomicroscopy. At the initial visit, patients were thoroughly informed of their pathology and instructed to stop rubbing their eyes. Eye rubbing cessation was assessed at all the follow-up visits at 6 months, 1 year, 2 years, 3 years, and yearly afterward. Corneal topography using the Pentacam® (Oculus®, Wetzlar, Germany) was used to obtain maximum and average anterior keratometry readings (Kmax and Kmean), as well as thinnest pachymetry (Pachymin, μm) in both eyes. Main outcome measures The main outcomes measured were maximum keratometry (Kmax), mean keratometry (Kmean), and thinnest pachymetry (Pachymin) values at various time points to assess for keratoconus progression. Keratoconus progression was defined as a significant augmentation of Kmax (>1D), Kmean (>1D), or significant diminution of Pachymin (>5%) throughout the total follow-up duration. Results One hundred fifty three eyes of seventy-seven patients (75.3% males) aged 26.4 years old, were followed for an average of 53 months. Over the course of the follow-up, there was no statistically significant variation of ∆Kmax (+0.04 ± 0.87; p = 0.34), ∆ Kmean (+0.30 ± 0.67; p = 0.27) nor ∆Pachymin (-4.36 ± 11.88; p = 0.64). Among the 26 of the 153 eyes which had at least one criterion of KC progression, 25 admitted continuing eye rubbing, or other at-risk behaviors. Conclusion This study suggests that a significant proportion of keratoconus patients are likely to remain stable if close monitoring and strict ARB cessation are achieved, without the need for further intervention.
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Mohaghegh S, Kangari H, Masoumi SJ, Bamdad S, Rahmani S, Abdi S, Fazil N, Shahbazi S. Prevalence and risk factors of keratoconus (including oxidative stress biomarkers) in a cohort study of Shiraz university of medical science employees in Iran. BMC Ophthalmol 2023; 23:188. [PMID: 37106365 PMCID: PMC10142163 DOI: 10.1186/s12886-023-02934-0] [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: 11/24/2022] [Accepted: 04/21/2023] [Indexed: 04/29/2023] Open
Abstract
BACKGROUND To determine the prevalence of keratoconus in Shiraz University of Medical Sciences Employees and the related risk factors including oxidative stress biomarkers. METHODS 2546 subjects' mean age ± SD, 40.35 ± 6.70 (46% male) were recruited. All participants underwent objective refraction using auto-refractometer and retinoscopy, followed by subjective refraction, and bio-microscopy. Pentacam imaging was performed for the detected keratoconus patients. The prevalence of keratoconus and frequency of the visual impairment among keratoconus cases were evaluated. Potential risk factors of sex, age, family history of keratoconus, body mass index ≥ 30 kg/m2, serum levels of glucose ≥ 100 mg/d, low-density-lipoprotein-cholesterol (LDL) ≥ 110 mg/dL, high-density-lipoprotein-cholesterol ≤ 40 mg/d, and triglycerides ≥ 150 mg/dL in the blood were evaluated. RESULTS The prevalence of keratoconus at least in one eye was 0.98% (95% CI: 0.6- 1.4%). The best corrected visual acuity in the keratoconus group was 0.06 ± 0.1 and the rest of the population was 0.01 ± 0.07 logMAR (p < 0.001). The frequency of visual impairment in the keratoconus group was zero. Odds ratios of the family history of keratoconus (21.00, 95% CI: 9.00-48.00, p < 0.001) and LDL ≥ 110 mg/dL (3.00, 95% CI: 1.20-6.40, p = 0.01) were significant. CONCLUSIONS Keratoconus is rare and is not considered a risk factor for visual impairment. A family history of keratoconus and elevated serum LDL levels are contributing risk factors, suggesting an inflammatory background for the disease. Serum levels of LDL ≥ 110 mg/dL in the blood increased the risk of keratoconus three folds.
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Affiliation(s)
- Sahar Mohaghegh
- Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Haleh Kangari
- Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Seyed Jalil Masoumi
- Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition and Food Sciences, Shiraz University of Medical Science, Shiraz, Iran
| | - Shahram Bamdad
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Saeed Rahmani
- Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Saeed Abdi
- Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nagham Fazil
- Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Saeedeh Shahbazi
- Labbafinejad Hospital, Shahid Beheshti University of Medical Sciences and health services, Tehran, Iran
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Akoto T, Cai J, Nicholas S, McCord H, Estes AJ, Xu H, Karamichos D, Liu Y. Unravelling the Impact of Cyclic Mechanical Stretch in Keratoconus-A Transcriptomic Profiling Study. Int J Mol Sci 2023; 24:7437. [PMID: 37108600 PMCID: PMC10139219 DOI: 10.3390/ijms24087437] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/04/2023] [Accepted: 04/16/2023] [Indexed: 04/29/2023] Open
Abstract
Biomechanical and molecular stresses may contribute to the pathogenesis of keratoconus (KC). We aimed to profile the transcriptomic changes in healthy primary human corneal (HCF) and KC-derived cells (HKC) combined with TGFβ1 treatment and cyclic mechanical stretch (CMS), mimicking the pathophysiological condition in KC. HCFs (n = 4) and HKCs (n = 4) were cultured in flexible-bottom collagen-coated 6-well plates treated with 0, 5, and 10 ng/mL of TGFβ1 with or without 15% CMS (1 cycle/s, 24 h) using a computer-controlled Flexcell FX-6000T Tension system. We used stranded total RNA-Seq to profile expression changes in 48 HCF/HKC samples (100 bp PE, 70-90 million reads per sample), followed by bioinformatics analysis using an established pipeline with Partek Flow software. A multi-factor ANOVA model, including KC, TGFβ1 treatment, and CMS, was used to identify differentially expressed genes (DEGs, |fold change| ≥ 1.5, FDR ≤ 0.1, CPM ≥ 10 in ≥1 sample) in HKCs (n = 24) vs. HCFs (n = 24) and those responsive to TGFβ1 and/or CMS. PANTHER classification system and the DAVID bioinformatics resources were used to identify significantly enriched pathways (FDR ≤ 0.05). Using multi-factorial ANOVA analyses, 479 DEGs were identified in HKCs vs. HCFs including TGFβ1 treatment and CMS as cofactors. Among these DEGs, 199 KC-altered genes were responsive to TGFβ1, thirteen were responsive to CMS, and six were responsive to TGFβ1 and CMS. Pathway analyses using PANTHER and DAVID indicated the enrichment of genes involved in numerous KC-relevant functions, including but not limited to degradation of extracellular matrix, inflammatory response, apoptotic processes, WNT signaling, collagen fibril organization, and cytoskeletal structure organization. TGFβ1-responsive KC DEGs were also enriched in these. CMS-responsive KC-altered genes such as OBSCN, CLU, HDAC5, AK4, ITGA10, and F2RL1 were identified. Some KC-altered genes, such as CLU and F2RL1, were identified to be responsive to both TGFβ1 and CMS. For the first time, our multi-factorial RNA-Seq study has identified many KC-relevant genes and pathways in HKCs with TGFβ1 treatment under CMS, suggesting a potential role of TGFβ1 and biomechanical stretch in KC development.
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Affiliation(s)
- Theresa Akoto
- Department of Cellular Biology & Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Jingwen Cai
- Department of Cellular Biology & Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Sarah Nicholas
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- Department of Pharmaceutical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Hayden McCord
- Department of Cellular Biology & Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Amy J. Estes
- Department of Ophthalmology, Augusta University, Augusta, GA 30912, USA
- James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Hongyan Xu
- Department of Population Health Sciences, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Dimitrios Karamichos
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- Department of Pharmaceutical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Yutao Liu
- Department of Cellular Biology & Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
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11
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Gao S, Chen Y, Shi F, Peng Y, Xu C, Chen Z, Zhu W, Xu X, Tang W, Tan Z, Xu Y, Ren Y, Zhang X, Chen X. LKG-Net: lightweight keratoconus grading network based on corneal topography. BIOMEDICAL OPTICS EXPRESS 2023; 14:799-814. [PMID: 36874500 PMCID: PMC9979687 DOI: 10.1364/boe.480564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/01/2022] [Accepted: 12/10/2022] [Indexed: 06/18/2023]
Abstract
Keratoconus (KC) is a noninflammatory ectatic disease characterized by progressive thinning and an apical cone-shaped protrusion of the cornea. In recent years, more and more researchers have been committed to automatic and semi-automatic KC detection based on corneal topography. However, there are few studies about the severity grading of KC, which is particularly important for the treatment of KC. In this work, we propose a lightweight KC grading network (LKG-Net) for 4-level KC grading (Normal, Mild, Moderate, and Severe). First of all, we use depth-wise separable convolution to design a novel feature extraction block based on the self-attention mechanism, which can not only extract rich features but also reduce feature redundancy and greatly reduce the number of parameters. Then, to improve the model performance, a multi-level feature fusion module is proposed to fuse features from the upper and lower levels to obtain more abundant and effective features. The proposed LKG-Net was evaluated on the corneal topography of 488 eyes from 281 people with 4-fold cross-validation. Compared with other state-of-the-art classification methods, the proposed method achieves 89.55% for weighted recall (W_R), 89.98% for weighted precision (W_P), 89.50% for weighted F1 score (W_F1) and 94.38% for Kappa, respectively. In addition, the LKG-Net is also evaluated on KC screening, and the experimental results show the effectiveness.
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Affiliation(s)
- Song Gao
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
- These authors contributed equally to this paper
| | - Yingjie Chen
- Department of Ophthalmology, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, 215006, China
- These authors contributed equally to this paper
| | - Fei Shi
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
| | - Yuanyuan Peng
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
| | - Chenan Xu
- State Key Laboratory of Radiation Medicine and Protection, Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, and School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou 215006, China
| | - Zhongyue Chen
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
| | - Weifang Zhu
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
| | - Xin Xu
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
| | - Wei Tang
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
| | - Zhiwei Tan
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
| | - Yue Xu
- Department of Ophthalmology, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, 215006, China
| | - Yaru Ren
- Department of Ophthalmology, Soochow University-Affiliated First Hospital, Suzhou, Suzhou, 215006, China
| | - Xiaofeng Zhang
- Department of Ophthalmology, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, 215006, China
- Department of Ophthalmology, Soochow University-Affiliated First Hospital, Suzhou, Suzhou, 215006, China
| | - Xinjian Chen
- MIPAV Lab, School of Electronics and Information Engineering, Soochow University, Suzhou, 215006, China
- State Key Laboratory of Radiation Medicine and Protection, Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, and School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou 215006, China
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12
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McMonnies CW. Mechanisms of corneal trauma in response to rubbing and other intraocular pressure elevating activities in keratoconus. EXPERT REVIEW OF OPHTHALMOLOGY 2022. [DOI: 10.1080/17469899.2022.2153119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Charles W McMonnies
- Faculty of Medicine and Health, School of Optometry and Vision Science, University of New South Wales
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13
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Cheng WY, Yang SY, Huang XY, Zi FY, Li HP, Sheng XL. Identification of genetic variants in five chinese families with keratoconus: Pathogenicity analysis and characteristics of parental corneal topography. Front Genet 2022; 13:978684. [PMID: 36276932 PMCID: PMC9583916 DOI: 10.3389/fgene.2022.978684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 09/12/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose: The study aims to identify genetic variants in five Chinese families with Keratoconus (KC) and describe the characteristics of parental corneal topography. Methods: Fifteen participants, including five probands and ten parents from five Chinese families with KC, were recruited for genetic and clinical analyses. Targeted next-generation sequencing using a custom-designed panel for KC was applied on the probands for variant identification. Sanger sequencing and cosegregation analysis of the suspected pathogenic variants were performed on the family members. The pathogenicities of variants were evaluated according to the American College of Medical Genetics and Genomics guidelines (ACMG). Pentacam 3D anterior segment analysis system was applied for keratectasia detection and the Corvis ST for corneal biomechanics measurement. Fifteen parameters were recorded, including nine keratectasia indicators (BAD-D, TP, Kmax, Df, Db, Dp, Dt, Da, ARTH), six corneal biomechanical indicators (CBI, DA ratio, SP-A1, IR, bIOP, TBI). Results: A total of six novel variants, including five missense variants and one frameshift variant, were detected in the HMX1, SLC4A11, TGFBI, PIKFYVE, and ZEB1 genes in five probands, all of which showed co-segregation of genotype and clinical phenotype and were determined to be pathogenic. The genetic model was autosomal dominant (AD) in four families and autosomal recessive (AR) in 1 family. The analysis of keratectasia and corneal biomechanical indicators of the proband’s parents (first-generation relatives) in AD families revealed that there were several abnormal indexes in BAD-D, TP, Kmax, Df, Db, Dp, Dt, Da, CBI, DA ratio, SP-A1, IR, bIOP and TBI test indexes, showing clinical characteristics of incipient KC. Conclusion: Our study shows that variants in HMX1, SLC4A11, TGFBI, PIKFYVE, and ZEB1 were associated with KC. Our study extends the gene spectrum associated with KC, provides novel insights into KC phenotypic assessments, and contributes to early diagnosis for these patients.
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Affiliation(s)
- Wan-Yu Cheng
- Ningxia Eye Hospital, People’s Hospital of Ningxia Hui Autonomous Region, Third Clinical Medical College of Ningxia Medical University, Yinchuan, China
| | - Shang-Ying Yang
- Ningxia Eye Hospital, People’s Hospital of Ningxia Hui Autonomous Region, Third Clinical Medical College of Ningxia Medical University, Yinchuan, China
| | - Xiao-Yu Huang
- Ningxia Eye Hospital, People’s Hospital of Ningxia Hui Autonomous Region, Third Clinical Medical College of Ningxia Medical University, Yinchuan, China
| | - Fei-Yin Zi
- Ningxia Eye Hospital, People’s Hospital of Ningxia Hui Autonomous Region, Third Clinical Medical College of Ningxia Medical University, Yinchuan, China
| | - Hui-Ping Li
- Ningxia Eye Hospital, People’s Hospital of Ningxia Hui Autonomous Region, Third Clinical Medical College of Ningxia Medical University, Yinchuan, China
- *Correspondence: Hui-Ping Li, ; Xun-Lun Sheng,
| | - Xun-Lun Sheng
- Gansu Aier Ophthalmology and Optometry Hospital, Lanzhou City, China
- *Correspondence: Hui-Ping Li, ; Xun-Lun Sheng,
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14
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Akoto T, Li JJ, Estes AJ, Karamichos D, Liu Y. The Underlying Relationship between Keratoconus and Down Syndrome. Int J Mol Sci 2022; 23:ijms231810796. [PMID: 36142709 PMCID: PMC9503764 DOI: 10.3390/ijms231810796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Keratoconus (KC) is one of the most significant corneal disorders worldwide, characterized by the progressive thinning and cone-shaped protrusion of the cornea, which can lead to severe visual impairment. The prevalence of KC varies greatly by ethnic groups and geographic regions and has been observed to be higher in recent years. Although studies reveal a possible link between KC and genetics, hormonal disturbances, environmental factors, and specific comorbidities such as Down Syndrome (DS), the exact cause of KC remains unknown. The incidence of KC ranges from 0% to 71% in DS patients, implying that as the worldwide population of DS patients grows, the number of KC patients may continue to rise significantly. As a result, this review aims to shed more light on the underlying relationship between KC and DS by examining the genetics relating to the cornea, central corneal thickness (CCT), and mechanical forces on the cornea, such as vigorous eye rubbing. Furthermore, this review discusses KC diagnostic and treatment strategies that may help detect KC in DS patients, as well as the available DS mouse models that could be used in modeling KC in DS patients. In summary, this review will provide improved clinical knowledge of KC in DS patients and promote additional KC-related research in these patients to enhance their eyesight and provide suitable treatment targets.
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Affiliation(s)
- Theresa Akoto
- Department of Cellular Biology & Anatomy, Augusta University, Augusta, GA 30912, USA
| | - Jiemin J. Li
- Department of Cellular Biology & Anatomy, Augusta University, Augusta, GA 30912, USA
| | - Amy J. Estes
- Department of Ophthalmology, Augusta University, Augusta, GA 30912, USA
- James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Dimitrios Karamichos
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- Department of Pharmaceutical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Yutao Liu
- Department of Cellular Biology & Anatomy, Augusta University, Augusta, GA 30912, USA
- James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Correspondence: ; Tel.: +1-706-721-2015
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15
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Joshi MR, Voison KJ, Piano M, Farnon N, Bex PJ. A novel tool for quantitative measurement of distortion in keratoconus. Eye (Lond) 2022:10.1038/s41433-022-02240-x. [PMID: 36104521 PMCID: PMC9472732 DOI: 10.1038/s41433-022-02240-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 09/05/2022] [Indexed: 11/23/2022] Open
Abstract
Background Keratoconus is associated with thinning and anterior protrusion of the cornea resulting in the symptoms of blurry and distorted vision. The commonly used clinical vision tests such as visual acuity and contrast sensitivity may not reflect the symptoms experienced in keratoconus and there are no quantitative tools to measure visual distortion. In this study, we used a quantitative test based on vernier alignment and field matching techniques to quantify visual distortion in keratoconus and assess its relation to corneal structural changes. Methods A total of 50 participants (25 keratoconus and 25 visually normal) completed the experiment where they aligned supra-threshold white target circles in opposite field in reference to guidelines and circles to complete a square structure monocularly. The task was repeated five times and the global distortion index (GDI) and global uncertainty index (GUI) were calculated as the mean and standard deviation respectively of local perceived misalignment of target circles over five trials. Results Both GDI and GUI were higher in participants with keratoconus compared to controls (p < 0.01). Both parameters correlated with the best corrected visual acuity, maximum corneal curvature (Kmax), topographical keratoconus classification (TKC) and central corneal thickness (CCT). Conclusion Our findings show that the quantitative measure of distortion could be a useful tool for behavioural assessment of progressive keratoconus.
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16
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Santodomingo-Rubido J, Carracedo G, Suzaki A, Villa-Collar C, Vincent SJ, Wolffsohn JS. Keratoconus: An updated review. Cont Lens Anterior Eye 2022; 45:101559. [PMID: 34991971 DOI: 10.1016/j.clae.2021.101559] [Citation(s) in RCA: 183] [Impact Index Per Article: 91.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/23/2021] [Accepted: 12/12/2021] [Indexed: 02/06/2023]
Abstract
Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20- to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal cross-linking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus.
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Affiliation(s)
| | - Gonzalo Carracedo
- Department of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Asaki Suzaki
- Clinical Research and Development Center, Menicon Co., Ltd., Nagoya, Japan
| | - Cesar Villa-Collar
- Department of Pharmacy, Biotechnology, Nutrition, Optics and Optometry, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Madrid, Spain
| | - Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Centre for Vision and Eye Research, Queensland University of Technology, Brisbane, Australia
| | - James S Wolffsohn
- School of optometry, Health and Life Sciences, Aston University, Birmingham B4 7ET, United Kingdom
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17
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Gurnani B, Kaur K, Tripathy K. Is there a genetic link between Keratoconus and Fuch's endothelial corneal dystrophy? Med Hypotheses 2021; 157:110699. [PMID: 34666260 DOI: 10.1016/j.mehy.2021.110699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/19/2021] [Accepted: 10/04/2021] [Indexed: 10/20/2022]
Abstract
Keratoconus (KC) is a noninflammatory, bilateral, progressive corneal stromal thinning disorder that leads to corneal ectasia, central anterior corneal stromal scarring, irregular myopic astigmatism, and reduced visual acuity. Fuchs endothelial corneal dystrophy (FECD) is bilateral, sporadic, or autosomal dominant, non-inflammatory, dystrophy involving the corneal endothelium. As the dystrophy evolves, the major complaints include glare, halos, and reduced visual acuity. Very rarely, both the pathologies can co-exist in the same patient. After the initial report of KC with FECD, there have been nearly 70 cases of coexistence reported in the literature till now. The reported number of cases varies from region to region and the majority of cases have no documented family history, hence it is difficult to approximate the incidence and prevalence based on the available literature. Hence, we hypothesize that both pathologies have probably the same genetic link. Available literature supporting the hypothesis has been discussed. We have also discussed various probable mechanisms of coexistence and proposed a management algorithm while assessing and attempting surgery in these patients. We also propose that all these patients must undergo genetic screening and counselling to prevent the spread of these pathologies in future generations.
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Affiliation(s)
- Bharat Gurnani
- Consultant Cataract, Cornea and Refractive Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry 605007, India
| | - Kirandeep Kaur
- Consultant Cataract, Pediatric Ophthalmology and Squint Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry 605007, India
| | - Koushik Tripathy
- Consultant Retina and Uvea Services, ASG Eye Hospital, Kolkata, India
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18
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Ong APC, Zhang J, Vincent AL, McGhee CNJ. Megalocornea, anterior megalophthalmos, keratoglobus and associated anterior segment disorders: A review. Clin Exp Ophthalmol 2021; 49:477-497. [PMID: 34114333 DOI: 10.1111/ceo.13958] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 01/21/2023]
Abstract
Megalocornea and anterior megalophthalmos (megalocornea spectrum) disorders are typically defined by corneal diameter > 12.5 mm in the absence of elevated intraocular pressure. Clinical features overlap with keratoglobus but are distinct from buphthalmos and severe (globus) keratoconus. Megalocornea spectrum disorders and keratoglobus are primarily congenital disorders, often with syndromic associations; both can present with large and thin corneas, creating difficulty in diagnosis, however, only keratoglobus is typically progressive. Molecular genetics provide significant insight into underlying aetiologies. Nonetheless, careful clinical assessment remains intrinsic to diagnosis. Surgical management can be challenging due to the enlarged ciliary ring and weakened zonules in megalocornea spectrum disorders and the extreme corneal thinning of keratoglobus. In this review, the established literature on measurement of corneal diameter, diagnosis of megalocornea, anterior megalophthalmos and keratoglobus, differentiation from severe keratoconus, recent molecular genetics research and key surgical modalities in the management of these rare disorders are outlined and discussed.
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Affiliation(s)
- Aaron P C Ong
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Department of Ophthalmology, Southern District Health Board, Dunedin, New Zealand
| | - Jie Zhang
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Andrea L Vincent
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Charles N J McGhee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Donoso R, Rodríguez Á, Esteffan K, Lagos C, Aránguiz D, Hernández N. Analysis of OPD-Scan and Pentacam Parameters for Early Keratoconus Detection. Am J Ophthalmol 2021; 226:235-242. [PMID: 33529586 DOI: 10.1016/j.ajo.2021.01.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/15/2020] [Accepted: 01/20/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND PURPOSE: To evaluate Pentacam and OPD-Scan parameters in the early detection of keratoconus. DESIGN Retrospective case-control study. METHODS Case group included 50 clinically unaffected fellow eyes diagnosed with asymmetric keratoconus showing subtle qualitative changes at the 0.5-D sensitivity OPD-Scan scale, as well as normal anterior and back elevation difference map at Belin/Ambrósio enhanced ectasia display (BAD) at the Pentacam. Control group included 172 normal eyes that underwent Lasik surgery and presented no complications throughout the 2-year follow-up period. OPD-Scan and Pentacam parameters were compared, calculating sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). A multivariate analysis was performed using Pentacam or OPD-Scan variables, and a model using variables of both devices. RESULTS Pentacam variables with AUC ≥0.8 were keratoconus index (0.85), index of height decentration (0.81), and overall deviation at BAD (0.8). OPD-Scan variables with AUC ≥0.8 were keratoconus prediction index (0.83), surface asymmetry index (0.83), and total of higher-order trefoil aberration (0.8). In the multivariate analysis, the AUC was 0.85 in the case of OPD-Scan whereas it was 0.89 in the case of Pentacam. When combining all variables from the 2 devices, the AUC was 0.93, with a sensitivity of 82% and a specificity of 94%. CONCLUSIONS Several parameters of OPD-Scan and Pentacam can be useful to differentiate cases from normal control eyes, demonstrating even better results when combining parameters of both devices. Anterior corneal indexes were the most important parameters to discriminate both groups.
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Affiliation(s)
- Rodrigo Donoso
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile.
| | - Álvaro Rodríguez
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
| | - Karim Esteffan
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
| | - Claudio Lagos
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
| | - Diego Aránguiz
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
| | - Nicolás Hernández
- From the Department of Ophthalmology, Faculty of Medicine, Universidad de Chile (R.D., A.R., K.E.), Clínica Oftalmológica Pasteur (R.D., A.R., K.E., D.A., N.H.), and Department of Radiology, Pontificia Universidad Católica de Chile (C.L.), Santiago, Chile
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Keratoconus concordance in monozygotic twins before and after combined CXL/PRK (Athens Protocol) using Scheimflung and OCT tomography. J Cataract Refract Surg 2021; 48:83-88. [PMID: 34091554 DOI: 10.1097/j.jcrs.0000000000000691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/24/2021] [Indexed: 11/26/2022]
Abstract
PUPOSE To describe the concordance of keratoconus expression in two pairs of monozygotic twins before and after a combined CXL/PRK procedure. SETTING Private Ambulatory Eye Surgery Unit. DESIGN Retrospective Interventional Twin Study. METHODS Two pairs of male monozygotic twins with keratoconus (KCN) were studied retrospectively. Improvement of flattest (k1) and steepest (k2) keratometry, Index of Height Decentration (IHD), corneal thickness at thinnest point and corneal epithelial thickness measured by AS-OCT and Scheimpflug tomography was compared between respective eyes of monozygotic twin siblings 1 to 5 years after the application of combined corneal cross linking (CXL) and topography guided photorefractive keratectomy (PRK) of part of the refractive error (the Athens Protocol). RESULTS Significant improvement was noted in all the keratometric indices of all 8 eyes after the combined CXL/PRK procedure.The difference in k1, k2, IHD corneal thickness at thinnest point and corneal epithelial thickness percentage improvement between the right eyes of each pair of twins was statistically significant 1 and 5 years post-operatively (P < .05). Statistically significant discordance in the aforementioned parameters percentage improvement was likewise observed between the left eyes of each pair of twins (P < .05). CONCLUSIONS Although a genetic predisposition in KCN is well documented, the discordance in keratometric indices improvement after a CXL/PRK procedure between respective eyes of monozygotic twins suggests that environmental influences may contribute to the disease expression as well. Variable degree of synergy in a combined CXL/PRK procedure may also explain the aforementioned discordant improvement.
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Kristianslund O, Drolsum L. Prevalence of keratoconus in persons with Down syndrome: a review. BMJ Open Ophthalmol 2021; 6:e000754. [PMID: 33981858 PMCID: PMC8061858 DOI: 10.1136/bmjophth-2021-000754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/04/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose Keratoconus is a vision-threatening condition, and there is a need for knowledge about the occurrence in subgroups of the population. The progression of the disease can be effectively stopped, and vision may be restored, if keratoconus is diagnosed at an early stage. The purpose of this review was to evaluate the literature of the prevalence of keratoconus in persons with Down syndrome. Methods We conducted a literature review of keratoconus prevalence in persons with Down syndrome. A thorough search was performed in Pubmed (Medline), and the quality of evidence was evaluated. Results The literature review identified 20 relevant studies, which reported keratoconus in 0%–71% of persons with Down syndrome. These studies varied greatly in design, patient selection, sample sizes and mean age, and the quality of evidence concerning estimates for the prevalence of keratoconus was generally evaluated as low. Most studies that included adults reported high prevalences of keratoconus–in many studies more than 10-fold the prevalence in the general population. No large screening studies in persons with Down syndrome were identified. Conclusions The present review showed that the prevalence of keratoconus in persons with Down syndrome is higher than in the general population. However, estimates from previous studies vary widely. Screening for keratoconus in this group should be considered.
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Affiliation(s)
- Olav Kristianslund
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Liv Drolsum
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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Burdon KP, Vincent AL. Insights into keratoconus from a genetic perspective. Clin Exp Optom 2021; 96:146-54. [DOI: 10.1111/cxo.12024] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 10/18/2012] [Accepted: 10/30/2012] [Indexed: 01/08/2023] Open
Affiliation(s)
- Kathryn P Burdon
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia,
| | - Andrea L Vincent
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
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Fan gaskin JC, Good WR, Jordan CA, Patel DV, Mcghee CN. The Auckland keratoconus study: Identifying predictors of acute corneal hydrops in keratoconus. Clin Exp Optom 2021; 96:208-13. [DOI: 10.1111/cxo.12048] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/13/2013] [Accepted: 01/17/2013] [Indexed: 11/27/2022] Open
Affiliation(s)
- Jennifer C Fan gaskin
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - William R Good
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Charlotte A Jordan
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Dipika V Patel
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Charles Nj Mcghee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
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Kristianslund O, Drolsum L. Prevalence of Keratoconus in Persons With Down Syndrome in a National Registry in Norway. JAMA Netw Open 2021; 4:e210814. [PMID: 33666660 PMCID: PMC7936259 DOI: 10.1001/jamanetworkopen.2021.0814] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This cross-sectional study evaluates the association of keratoconus with Down syndrome by estimation of the prevalence of keratoconus in persons with Down syndrome in Norway.
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Affiliation(s)
- Olav Kristianslund
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Liv Drolsum
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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Lin KK, Lee JS, Hou CH, Chen WM, Hsiao CH, Chen YW, Yeh CT, See LC. The Sociodemographic and Risk Factors for Keratoconus: Nationwide Matched Case-Control Study in Taiwan, 1998-2015. Am J Ophthalmol 2021; 223:140-148. [PMID: 33007273 DOI: 10.1016/j.ajo.2020.09.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 12/30/2022]
Abstract
PURPOSE The aim of this study was to determine the sociodemographic and risk factors for keratoconus (KC) patients with a nationwide Asian database. DESIGN Population-based matched case-control study. METHODS We performed a secondary data analysis of the Taiwan National Health Insurance Research Database (NHIRD). Cases were patients with newly diagnosed KC in 1998-2015. Controls were patients without KC and matched 4:1 with the KC cases by age, sex, and index date. Comorbidities diagnosed before KC included diabetes mellitus (DM), asthma, allergic rhinitis, mitral valve prolapse, collagen vascular disease, aortic aneurysm, Down syndrome, sleep apnea, depression, hyperlipidemia, astigmatism, and myopia. Conditional logistic regression with forward selection were used to obtain risk factors for KC. RESULTS A total of 5,055 patients with KC were matched with 20,220 controls. The average age at KC first diagnosis was 29.76 years. Individuals who lived in suburban and rural area had lower odds ratio of KC (adjusted odds ratio [OR] 0.86, 95% confidence interval [CI] 0.80-0.94; and 0.73, 95% CI 0.67-0.79; respectively) when comparing with those who lived in urban area. Multivariate analysis revealed that Down syndrome, astigmatism, myopia, allergic rhinitis, and asthma were positively associated with KC with adjusted odds ratios (adjusted OR 8.69, 95% CI 3.74-20.19; 6.23, 95% CI 5.35-7.24; 2.99, 95% CI 2.70-3.32; 1.22, 95% CI 1.14-1.32; and 1.18, 95% CI 1.07-1.30, respectively). On the other hand, hyperlipidemia, depression, and DM (uncomplicated and complicated) were negatively associated with KC (adjusted OR 0.67, 95% CI 0.59-0.77; 0.58, 95% CI 0.48-0.71; 0.77, 95% CI 0.64-0.93; and 0.61, 95% CI 0.44-0.86, respectively). CONCLUSIONS Our study found that patients with hyperlipidemia, depression, or DM were less likely to have KC, and patients with asthma, allergic rhinitis, astigmatism, myopia, or Down syndrome had higher odds ratio of KC.
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Results of Corneal Collagen Cross-Linking in Adolescents with Progressive Keratoconus - A Prospective Study. J Cataract Refract Surg 2021; 47:1333-1337. [PMID: 33769766 DOI: 10.1097/j.jcrs.0000000000000617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 02/10/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE Evaluate the safety and efficacy of epi-off corneal cross-linking (CXL) in adolescents with progressive keratoconus (KC). SETTING Private clinical practice DESIGN:: Nonrandomized prospective clinical trial METHODS:: 230 adolescent patients aged 10-19 years old with progressive keratoconus (increasing maximum keratometry (Kmax) or astigmatism of ≥ 1 D associated with decreased corrected distance visual acuity (CDVA)) underwent CXL. Exclusion criteria were age at time of CXL < 10 years or > 19 years, corneas that were thinner than 400 μm or demonstrated central corneal scarring, history of herpetic eye disease, or pregnancy or nursing. Follow up examinations of uncorrected distance visual acuity (UDVA), CDVA, Kmax and minimum pachymetry occurred on 130 eyes at 1 year, 77 eyes at 2 years and 55 eyes at 3 years post-CXL. RESULTS UCVA significantly improved from preop to 1, 2 and 3 years post-CXL. CDVA significantly improved from preop to 1, 2 and 3 years post-CXL. Kmax significantly reduced (improved) from preop to 1 and 3 years post-CXL and reduced (improved) (p=0.22) from preop to two years post-CXL. Minimum pachymetry decreased significantly from preop to 1, 2 and 3 years post-CXL. CONCLUSIONS CXL in patients aged 10-19 years old is safe and efficacious, halts progression of KC and can improve UCVA, CDVA and Kmax. Minimum pachymetry decreases and stabilizes post-CXL. Ophthalmologists should encourage adolescent patients with KC to obtain prompt evaluation and possible CXL to halt progression of the disease.
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Crawford AZ, Zhang J, Gokul A, McGhee CNJ, Ormonde SE. The Enigma of Environmental Factors in Keratoconus. Asia Pac J Ophthalmol (Phila) 2020; 9:549-556. [PMID: 33284230 DOI: 10.1097/apo.0000000000000334] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Keratoconus is an ectatic disorder with highly complex and varied causes including genetic variations and environmental factors. Its prevalence varies widely between regions and countries. Many environmental factors have been proposed to be associated with keratoconus, but the interpretation of their individual contributions is difficult due to the presence of many confounding variables. The current literature was reviewed to evaluate the strength of the associations and the causative effects of environmental factors on keratoconus. Ethnicity and consanguinity have been revealed as important determinants for geographical variations in keratoconus prevalence. Eye rubbing, atopy, floppy eyelid syndrome, contact lens wear, pregnancy, and thyroid hormone disturbances are likely associated with keratoconus. The first 4 factors can induce ocular surface inflammation, matrix metalloproteinase release, and keratocyte apoptosis, consistent with the postulated etiology of keratoconus. The associations of keratoconus with UV exposure, cigarette smoking, personality, and sex were less convincing once confounding factors were considered. Future studies powered for multivariate analysis of factors discussed will hopefully shed light on what is truly important in the development and progression of keratoconus.
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Affiliation(s)
- Alexandra Z Crawford
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Ophthalmology, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Jie Zhang
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Akilesh Gokul
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Charles N J McGhee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Ophthalmology, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Sue E Ormonde
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Ophthalmology, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
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Mazharian A, Panthier C, Courtin R, Jung C, Rampat R, Saad A, Gatinel D. Incorrect sleeping position and eye rubbing in patients with unilateral or highly asymmetric keratoconus: a case-control study. Graefes Arch Clin Exp Ophthalmol 2020; 258:2431-2439. [PMID: 32524239 PMCID: PMC7584543 DOI: 10.1007/s00417-020-04771-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/19/2020] [Accepted: 05/25/2020] [Indexed: 12/19/2022] Open
Abstract
PURPOSE To evaluate eye rubbing and sleeping position in patients with Unilateral or Highly Asymmetric Keratoconus (UHAKC). METHODS Case-control study of consecutive UHAKC patients diagnosed at the Rothschild Foundation. Controls were age- and sex-matched, randomly selected refractive surgery clinic patients. Patients self-administered questionnaires regarding their family history of keratoconus, eye rubbing, and sleeping habits. All the eyes underwent a comprehensive ocular examination. Logistic regression was used to analyze univariate and multivariate data to identify risk factors for keratoconus. RESULTS Thirty-three UHAKC patients and 64 controls were included. Univariate analyses showed that daytime eye rubbing [OR = 172.78], in the morning [OR = 24.3], or in eyes with the steepest keratometry [OR = 21.7] were significantly different between groups. Allergy [OR = 2.94], red eyes in the morning [OR = 6.36], and sleeping on stomach/sides [OR = 14.31] or on the same side as the steepest keratometry [OR = 94.72] were also significantly different. The multivariate model also showed statistical significance for most factors including daytime eye rubbing [OR = 134.96], in the morning [OR = 24.86], in the steepest eye [OR = 27.56], and sleeping on stomach/sides [OR = 65.02] or on the steepest side [OR = 144.02]. A univariate analysis in UHAKC group, comparing the worse and better eye, showed that eye rubbing [OR = 162.14] and sleeping position [OR = 99.74] were significantly (p < 0.001) associated with the worse eye. CONCLUSION Our data suggests that vigorous eye rubbing and incorrect sleeping position are associated with UHAKC. This is especially true in rubbing the most afflicted eye, and contributory sleep position, including positions placing pressure on the eye with the steepest keratometry.
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Affiliation(s)
- Adrien Mazharian
- Ophthalmology department, Fondation Ophtalmologique Adolphe de Rothschild, 25 Rue Manin, 75019, Paris, France
| | - Christophe Panthier
- Ophthalmology department, Fondation Ophtalmologique Adolphe de Rothschild, 25 Rue Manin, 75019, Paris, France
- Institut Laser Vision Noémie de Rothschild, Paris, France
| | - Romain Courtin
- Ophthalmology department, Fondation Ophtalmologique Adolphe de Rothschild, 25 Rue Manin, 75019, Paris, France
- Institut Laser Vision Noémie de Rothschild, Paris, France
| | - Camille Jung
- Clinical Research Center, Biological Resources Center, Centre Hospitalier Intercommunal de Créteil, Créteil, France
| | - Radhika Rampat
- Ophthalmology department, Fondation Ophtalmologique Adolphe de Rothschild, 25 Rue Manin, 75019, Paris, France
- Institut Laser Vision Noémie de Rothschild, Paris, France
| | - Alain Saad
- Ophthalmology department, Fondation Ophtalmologique Adolphe de Rothschild, 25 Rue Manin, 75019, Paris, France
- Institut Laser Vision Noémie de Rothschild, Paris, France
- Department of Ophthalmology, American University of Beirut - Medical Center, Beirut, Lebanon
| | - Damien Gatinel
- Ophthalmology department, Fondation Ophtalmologique Adolphe de Rothschild, 25 Rue Manin, 75019, Paris, France.
- Institut Laser Vision Noémie de Rothschild, Paris, France.
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Short-term bilateral keratoconus progression after deep anterior lamellar keratoplasty in one eye and intracorneal ring segments and corneal crosslinking in the other due to eye rubbing. J Cataract Refract Surg 2020; 46:e44-e47. [PMID: 32925655 DOI: 10.1097/j.jcrs.0000000000000422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A 15-year-old boy had deep anterior lamellar keratoplasty in the right eye and intracorneal ring segments/corneal crosslinking in the left eye for the treatment of progressive keratoconus due to eye rubbing. He achieved a good surgical results, and 6 months later, the uncorrected distance visual acuity (UDVA) was 0.30 logarithm of the minimum angle of resolution (logMAR) in each eye, the refraction in the right eye was plano -2.75 × 135 = 0.30 logMAR and in the left eye was -0.75 -2.50 × 45 = 0.18 logMAR. Twelve months postoperatively, there was recurrence of intense eye rubbing. UDVA dropped, and bilateral corneal steepening was noted. Bilateral corneal crosslinking was performed along with an allergist consultation for eye rubbing control. Ten years later, his UDVA was 1.3 logMAR and 0.40 logMAR and corrected distance visual acuity was 0.10 logMAR and 0.18 logMAR in the right and left eyes, respectively.
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Keratoconus-susceptibility gene identification by corneal thickness genome-wide association study and artificial intelligence IBM Watson. Commun Biol 2020; 3:410. [PMID: 32737415 PMCID: PMC7395727 DOI: 10.1038/s42003-020-01137-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 07/10/2020] [Indexed: 02/07/2023] Open
Abstract
Keratoconus is a common ocular disorder that causes progressive corneal thinning and is the leading indication for corneal transplantation. Central corneal thickness (CCT) is a highly heritable characteristic that is associated with keratoconus. In this two-stage genome-wide association study (GWAS) of CCT, we identified a locus for CCT, namely STON2 rs2371597 (P = 2.32 × 10−13), and confirmed a significant association between STON2 rs2371597 and keratoconus development (P = 0.041). Additionally, strong STON2 expression was observed in mouse corneal epithelial basal cells. We also identified SMAD3 rs12913547 as a susceptibility locus for keratoconus development using predictive analysis with IBM’s Watson question answering computer system (P = 0.001). Further GWAS analyses combined with Watson could effectively reveal detailed pathways underlying keratoconus development. Yoshikatsu Hosoda et al. study the genetic basis for central corneal thickness (CCT) that is associated with keratoconus. They identify two susceptibility loci, STON2 rs2371597 and SMAD3 rs12913547, using two-step genome-wide association study (GWAS) and predictive analysis with IBM’s Watson question answering computer system, respectively.
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Yam GHF, Riau AK, Funderburgh ML, Mehta JS, Jhanji V. Keratocyte biology. Exp Eye Res 2020; 196:108062. [PMID: 32442558 DOI: 10.1016/j.exer.2020.108062] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/01/2020] [Accepted: 05/04/2020] [Indexed: 12/12/2022]
Abstract
The study of corneal stromal keratocytes is motivated by its strong association with corneal health and visual function. They play a dominant role in the maintenance of corneal homeostasis and transparency through the production of collagens, proteoglycans and corneal crystallins. Trauma-induced apoptosis of keratocytes and replacement by fibroblasts and myofibroblasts disrupt the stromal matrix organization, resulting in corneal haze formation and vision loss. It is, therefore, important to understand the biology and behaviours of keratocytes and the associated stromal cell types (like fibroblasts, myofibroblasts, stromal stem cells) in wound healing, corneal pathologies (including keratoconus, keratitis, endothelial disorders) as well as different ophthalmic situations (such as collagen crosslinking/photodynamic treatment, keratoplasty and refractive surgery, and topical medications). The recent development of ex vivo propagation of keratocytes and stromal stem cells, and their translational applications, either via stromal injection or incorporated in bioscaffold, have been shown to restore the corneal transparency and regenerate native stromal tissue in animal models of corneal haze and other disorders.
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Affiliation(s)
- Gary H F Yam
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Andri K Riau
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore
| | | | - Jodhbir S Mehta
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
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Loukovitis E, Kozeis N, Gatzioufas Z, Kozei A, Tsotridou E, Stoila M, Koronis S, Sfakianakis K, Tranos P, Balidis M, Zachariadis Z, Mikropoulos DG, Anogeianakis G, Katsanos A, Konstas AG. The Proteins of Keratoconus: a Literature Review Exploring Their Contribution to the Pathophysiology of the Disease. Adv Ther 2019; 36:2205-2222. [PMID: 31363996 PMCID: PMC6822850 DOI: 10.1007/s12325-019-01026-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Keratoconus (KC) is a complex, genetically heterogeneous multifactorial degenerative disorder characterized by corneal ectasia and thinning. Its incidence is approximately 1/2000-1/50,000 in the general population. KC is associated with moderate to high myopia and irregular astigmatism, resulting in severe visual impairment. KC structural abnormalities primarily relate to the weakening of the corneal collagen. Their understanding is crucial and could contribute to effective management of the disease, such as with the aid of corneal cross-linking (CXL). The present article critically reviews the proteins involved in the pathophysiology of KC, with particular emphasis on the characteristics of collagen that pertain to CXL. METHODS PubMed, MEDLINE, Google Scholar and GeneCards databases were screened for relevant articles published in English between January 2006 and June 2018. Keyword combinations of the words "keratoconus," "risk factor(s)," "genetics," "genes," "genetic association(s)," "proteins", "collagen" and "cornea'' were used. In total, 272 articles were retrieved, reviewed and selected, with greater weight placed on more recently published evidence. Based on the reviewed literature, an attempt was made to tabulate the up- and down-regulation of genes involved in KC and their protein products and to delineate the mechanisms involved in CXL. RESULTS A total of 117 proteins and protein classes have been implicated in the pathogenesis and pathophysiology of KC. These have been tabulated in seven distinct tables according to their gene coding, their biochemistry and their metabolic control. CONCLUSION The pathogenesis and pathophysiology of KC remain enigmatic. Emerging evidence has improved our understanding of the molecular characteristics of KC and could further improve the success rate of CXL therapies.
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Choroidal thickness in keratoconus. Int Ophthalmol 2019; 40:135-140. [PMID: 31432355 DOI: 10.1007/s10792-019-01156-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/22/2019] [Accepted: 08/14/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE Keratoconus is an ectatic eye disease characterized by progressive thinning and steepening of the cornea which leads to irregular astigmatism and visual function loss. Determination of choroidal thickness in keratoconus patients may help us to better understand and manage the keratoconus disease. Choroidal thickness may be a potential marker for disease activity in keratoconus patients. In this study, we aimed to determine choroidal thickness in keratoconus patients and compare the results with the age-matched control group. METHODS This is a prospective study with a control group. Keratometry and thinnest corneal thickness was measured and recorded in keratoconus patients. Choroidal thickness of all subjects was measured using an optical coherence tomography device (Spectralis OCT, version 6.0, Heidelberg Engineering, Germany) with an enhanced depth imaging mode without pupil dilation. Mean choroidal thickness of keratoconus patients was compared with healthy subjects. RESULTS One hundred and sixty eyes of 80 healthy subjects and 160 eyes of 80 keratoconus patients were included in the study. Mean thinnest corneal thickness of the keratoconus patients was 449.7 ± 3.2 microns. Mean corneal keratometry value and cylindrical refraction error in the keratoconus patients were 53.2 ± 0.2 and 3.3 ± 0.1 diopters, respectively. Mean choroidal thickness was 363.9 ± 59.8 and 328.4 ± 67.2 microns in keratoconus patients and healthy subjects, respectively. There was a very significant difference between keratoconus patients and healthy subjects in terms of choroidal thickness (P = 0.000). There was not a statistically significant correlation between choroidal thickness and thinnest corneal thickness in keratoconus patients (P = 0.814). CONCLUSION Choroidal thickness was found to be increased in keratoconus patients. Choroidal thickness could potentially become a new clinical marker for disease activity in keratoconus patients.
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Abstract
The scientific problem of epidemiology of keratoconus in different countries is covered in the article. The results of original studies were analyzed and a conclusion has been drawn that keratoconus is quite a common disease in the world.
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Affiliation(s)
- F I Abdulalieva
- National Centre of Ophthalmology named after acad. Zarifa Aliyeva, 32/15 Javadkhan St., Baku, Azerbaijan, AZ 1114
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35
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Litke AM, Samuelson S, Delaney KR, Sauvé Y, Chow RL. Investigating the Pathogenicity of VSX1 Missense Mutations and Their Association With Corneal Disease. Invest Ophthalmol Vis Sci 2019; 59:5824-5835. [PMID: 30535423 DOI: 10.1167/iovs.18-25490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Despite numerous studies associating Visual System Homeobox 1 (VSX1), with posterior polymorphous corneal dystrophy and keratoconus, its role in these diseases is unclear. Here we examine the pathogenicity of VSX1 missense mutations in vitro and in a mouse genetic model. Methods Vsx1 transcriptional repressor activity, protein stability, and subcellular localization activity, was examined using luciferase reporter-based assays, western blotting and immunolabeling, respectively, in transfected human embryonic kidney 293T cells. A genetic model for VSX1 p.P247R was generated to investigate pathogenicity of the mutation, in vivo. A wholemount confocal imaging approach on unfixed intact eyes was developed to examine corneal morphology, curvature, and thickness. Immunolabeling and electroretinography was used to examine retinal phenotype. Results A mutation corresponding to human VSX1 p.P247R led to enhanced transcriptional repressor activity, in vitro. A mouse model for VSX1 p.P247R did not have any observable corneal defect, but did exhibit an abnormal electroretinogram response characterized by a more prominent ON as opposed to OFF panretinal responsiveness. In vitro analysis of additional VSX1 missense mutations showed that they either enhanced repressor activity or did not alter activity. Conclusions Our results indicate that although VSX1 sequence variants can alter transcriptional activity, in the context of a mouse genetic model, at least one of these changes does not lead to corneal abnormalities. While we cannot exclude a role for VSX1 as a risk factor for corneal disease, on its own, it does not appear to play a major causative role.
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Affiliation(s)
| | - Sarah Samuelson
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Kerry R Delaney
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Yves Sauvé
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Robert L Chow
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
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Foster JW, Shinde V, Soiberman US, Sathe G, Liu S, Wan J, Qian J, Dauoud Y, Pandey A, Jun AS, Chakravarti S. Integrated Stress Response and Decreased ECM in Cultured Stromal Cells From Keratoconus Corneas. Invest Ophthalmol Vis Sci 2019; 59:2977-2986. [PMID: 30029277 PMCID: PMC5995483 DOI: 10.1167/iovs.18-24367] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Keratoconus (KC) is a multifactorial disease where progressive thinning and weakening of the cornea leads to loss of visual acuity. Although the underlying etiology is poorly understood, a major endpoint is a dysfunctional stromal connective tissue matrix. Using multiple individual KC corneas, we determined that matrix production by keratocytes is severely impeded due to an altered stress response program. Methods KC and donor (DN) stromal keratocytes were cultured in low glucose serum-free medium containing insulin, selenium and transferrin. Fibronectin, collagens and proteins related to their chaperone, processing and export, matrix metalloproteinase, and stress response related proteins were investigated by immunoblotting, immunocytochemistry, hydroxyproline quantification, and gelatin zymography. Multiplexed mass spectrometry was used for global proteomic profiling of 5 individual DN and KC cell culture. Transcription of selected proteins was assayed by qPCR. Results DN and KC cells showed comparable survival and growth. However, immunoblotting of selected ECM proteins and global proteomics showed decreased fibronectin, collagens, PCOLCE, ADAMTS2, BMP1, HSP47, other structural and cytoskeletal proteins in KC. Phosphorylated (p) eIF2α, a translation regulator and its target, ATF4 were increased in KC cultured cells and corneal sections. Conclusions The profound decrease in structural proteins in cultured KC cells and increase in the p-eIF2α, and ATF4, suggest a stress related blockade in structural proteins not immediately needed for cell survival. Therefore, this cell culture system reveals an intrinsic aggravated stress response with consequent decrease in ECM proteins as potential pathogenic underpinnings in KC.
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Affiliation(s)
- James W Foster
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Vishal Shinde
- Department of Ophthalmology, NYU Langone Health, New York, New York, United States
| | - Uri S Soiberman
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Gajanan Sathe
- Manipal Academy of Higher Education, Karnataka, India
| | - Sheng Liu
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Julius Wan
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Jiang Qian
- Department of Ophthalmology, NYU Langone Health, New York, New York, United States
| | - Yassine Dauoud
- Department of Ophthalmology, NYU Langone Health, New York, New York, United States
| | - Akhilesh Pandey
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Albert S Jun
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Shukti Chakravarti
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States.,Department of Ophthalmology, NYU Langone Health, New York, New York, United States
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Loukovitis E, Sfakianakis K, Syrmakesi P, Tsotridou E, Orfanidou M, Bakaloudi DR, Stoila M, Kozei A, Koronis S, Zachariadis Z, Tranos P, Kozeis N, Balidis M, Gatzioufas Z, Fiska A, Anogeianakis G. Genetic Aspects of Keratoconus: A Literature Review Exploring Potential Genetic Contributions and Possible Genetic Relationships with Comorbidities. Ophthalmol Ther 2018; 7:263-292. [PMID: 30191404 PMCID: PMC6258591 DOI: 10.1007/s40123-018-0144-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 01/24/2023] Open
Abstract
INTRODUCTION Keratoconus (KC) is a complex, genetically heterogeneous, multifactorial degenerative disorder that is accompanied by corneal ectasia which usually progresses asymmetrically. With an incidence of approximately 1 per 2000 and 2 cases per 100,000 population presenting annually, KC follows an autosomal recessive or dominant pattern of inheritance and is, apparently, associated with genes that interact with environmental, genetic, and/or other factors. This is an important consideration in refractive surgery in the case of familial KC, given the association of KC with other genetic disorders and the imbalance between dizygotic twins. The present review attempts to identify the genetic loci contributing to the different KC clinical presentations and relate them to the common genetically determined comorbidities associated with KC. METHODS The PubMed, MEDLINE, Google Scholar, and GeneCards databases were screened for KC-related articles published in English between January 2006 and November 2017. Keyword combinations of "keratoconus," "risk factor(s)," "genetics," "genes," "genetic association(s)," and "cornea" were used. In total, 217 articles were retrieved and analyzed, with greater weight placed on the more recent literature. Further bibliographic research based on the 217 articles revealed another 124 relevant articles that were included in this review. Using the reviewed literature, an attempt was made to correlate genes and genetic risk factors with KC characteristics and genetically related comorbidities associated with KC based on genome-wide association studies, family-based linkage analysis, and candidate-gene approaches. RESULTS An association matrix between known KC-related genes and KC symptoms and/or clinical signs together with an association matrix between identified KC genes and genetically related KC comorbidities/syndromes were constructed. CONCLUSION Twenty-four genes were identified as potential contributors to KC and 49 KC-related comorbidities/syndromes were found. More than 85% of the known KC-related genes are involved in glaucoma, Down syndrome, connective tissue disorders, endothelial dystrophy, posterior polymorphous corneal dystrophy, and cataract.
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Affiliation(s)
| | - Konstantinos Sfakianakis
- Division of Surgical Anatomy, Laboratory of Anatomy, Medical School, Democritus University of Thrace, University Campus, Alexandroupolis, Greece
| | - Panagiota Syrmakesi
- AHEPA University Hospital, Thessaloníki, Greece
- Ophthalmica Eye Institute, Thessaloníki, Greece
| | - Eleni Tsotridou
- Ophthalmica Eye Institute, Thessaloníki, Greece
- Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloníki, Greece
| | - Myrsini Orfanidou
- Ophthalmica Eye Institute, Thessaloníki, Greece
- Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloníki, Greece
| | - Dimitra Rafailia Bakaloudi
- Ophthalmica Eye Institute, Thessaloníki, Greece
- Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloníki, Greece
| | - Maria Stoila
- Ophthalmica Eye Institute, Thessaloníki, Greece
- Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloníki, Greece
| | - Athina Kozei
- Ophthalmica Eye Institute, Thessaloníki, Greece
- School of Pharmacology, University of Nicosia, Makedonitissis, Nicosia, Cyprus
| | | | | | | | | | | | - Zisis Gatzioufas
- Department of Ophthalmology, Cornea, Cataract and Refractive Surgery, University Hospital Basel, Basel, Switzerland
| | - Aliki Fiska
- Laboratory of Anatomy, Medical School, Democritus University of Thrace, University Campus, Alexandroupolis, Greece
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Karadağ AS, Bilgin B, Özdemir N. Keratokonus hastalarında UVA-Riboflavin korneal kollajen çapraz bağlama tedavisinin sonuçları. CUKUROVA MEDICAL JOURNAL 2018. [DOI: 10.17826/cumj.336939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Prevalence of Keratoconus in a Refractive Surgery Population. J Ophthalmol 2018; 2018:5983530. [PMID: 30271629 PMCID: PMC6146781 DOI: 10.1155/2018/5983530] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 08/07/2018] [Indexed: 12/14/2022] Open
Abstract
Objective This study examined the prevalence of keratoconus among patients who were interested in undergoing refractive surgery. Corneal tomography measurements were used to help detect keratoconus. Methods Adult subjects who presented to the private hospital Cataract and Refractive Surgery Unit (Abha, Saudi Arabia) for refractive surgery evaluation were considered for inclusion in this cross-sectional, retrospective study. All subjects were from the Aseer province, a southern, high-altitude region in Saudi Arabia, and presented between January and December 2017. The incidence of keratoconus and other refractive surgery contraindications were examined. Results A total of 2931 patients were considered for inclusion in analyses. Of these, 2280 patients (77.8%) were not candidates for refractive surgery. These 2280 patients had a mean age of 24.1 ± 6.6 years and 1231 patients (54.0%) were male. Of the subjects who did not undergo refractive surgery, 548 (24%) had keratoconus, 400 (17.5%) were keratoconus suspects, 344 (15.1%) had thin corneas, 321 (14.1%) had high myopia, and 52 (2.3%) had a high astigmatism. An additional 479 subjects (21%) were candidates for refractive surgery, but chose not to undergo a procedure. Conclusion The incidence of keratoconus in Saudi Arabian refractive surgery prospects was 18.7%. Keratoconus was the most common reason for not performing refractive surgery and accounted for 24.0% of cases in which surgery was not performed.
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Uysal BS, Yaman D, Sarac O, Akcay E, Cagil N. Sterile keratitis after uneventful corneal collagen cross-linking in a patient with Axenfeld-Rieger syndrome. Int Ophthalmol 2018; 39:1169-1173. [DOI: 10.1007/s10792-018-0907-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 03/22/2018] [Indexed: 11/28/2022]
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Validation of an Objective Keratoconus Detection System Implemented in a Scheimpflug Tomographer and Comparison With Other Methods. Cornea 2018; 36:689-695. [PMID: 28368992 DOI: 10.1097/ico.0000000000001194] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To validate a recently developed program for automatic and objective keratoconus detection (Keratoconus Assistant [KA]) by applying it to a new population and comparing it with other methods described in the literature. METHODS KA uses machine learning and 25 Pentacam-derived parameters to classify eyes into subgroups, such as keratoconus, keratoconus suspect, postrefractive surgery, and normal eyes. To validate this program, it was applied to 131 eyes diagnosed separately by experienced corneal specialists from 2 different centers (Fondation Rothschild, Paris, and Antwerp University Hospital [UZA]). The agreement of the KA classification with 7 other indices from the literature was assessed using interrater reliability and confusion matrices. The agreement of the 2 clinical classifications was also assessed. RESULTS For keratoconus, KA agreed in 92.6% of cases with the clinical diagnosis by UZA and in 98.0% of cases with the diagnosis by Rothschild. In keratoconus suspect and forme fruste detection, KA agreed in 65.2% (UZA) and 100% (Rothschild) of cases with the clinical assessments. This corresponds with a moderate agreement with a clinical assessment (κ = 0.594 and κ = 0.563 for Rothschild and UZA, respectively). The agreement with the other classification methods ranged from moderate (κ = 0.432; Score) to low (κ = 0.158; KISA%). Both clinical assessments agreed substantially (κ = 0.759) with each other. CONCLUSIONS KA is effective at detecting early keratoconus and agrees with trained clinical judgment. As keratoconus detection depends on the method used, we recommend using multiple methods side by side.
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Awad EA, Abou Samra WA, Torky MA, El-Kannishy AM. Objective and subjective diagnostic parameters in the fellow eye of unilateral keratoconus. BMC Ophthalmol 2017; 17:186. [PMID: 28985735 PMCID: PMC5639589 DOI: 10.1186/s12886-017-0584-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 10/03/2017] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Keratoconus (KC) is usually a bilateral corneal ectatic disease. For significant asymmetric presentation (so called unilateral KC), the fellow eye has the mildest and earliest form of the disease, which is typically called forme fruste keratoconus. The aim of this study was to evaluate the sensitivity and specificity of parameters derived from a Scheimpflug imaging system (Pentacam) as well as the changes in the quality of mesopic vision in the apparently normal fellow eye (forme fruste) to detect the earliest and most sensitive parameters. METHODS Patients with clinical keratoconus in one eye and forme fruste keratoconus in the fellow eye were compared to subjects with normal eyes. The patients were examined using a rotating Scheimpflug imaging system (Pentacam).The following parameters were evaluated: keratometry, minimum corneal thickness, pachymetry progression index (PPI), Ambrósio relational thickness (ART), posterior elevation, back difference elevation (BDE) and multimetric D index(D index). Receiver operating characteristic (ROC) curves were analyzed by evaluating the area under the curve (AUC) to detect the sensitivity and specificity of each parameter. Mesopic vision evaluations were performed by contrast sensitivity and glare tests for each group. RESULTS A total of 48 patients with clinical keratoconus in one eye and forme fruste keratoconus in the fellow eye and 72normal subjects were evaluated. In the clinical keratoconus eyes, the mean K, back difference elevation (BDE), pachymetric progression index maximum(PPI max), and multimetric D were significantly higher compared to the normal subjects, whereas the corneal pachymetry and Ambrósio relational thickness maximum (ART max) were significantly lower. In the forme fruste eyes, the ROC analysis showed that the AUC values of the mean K, thinnest pachymetry, ARTmax, BDE, D index, and PPI max were 0.82, 0.61, 0.88, 0. 67, and 0.64, respectively. The contrast sensitivity and glare tests were significantly affected in the forme fruste cases. CONCLUSION In forme fruste keratoconus eyes, the ART max is considered a highly sensitive objective parameter. Contrast sensitivity and glare is an important subjective test, which is affected in forme fruste patients.
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Affiliation(s)
- Eman A. Awad
- Ophthalmology Center, Faculty of Medicine, Mansoura University, 24 Al-Gomhoria street, Mansoura, Egypt
| | - Waleed A. Abou Samra
- Ophthalmology Center, Faculty of Medicine, Mansoura University, 24 Al-Gomhoria street, Mansoura, Egypt
| | - Magda A. Torky
- Ophthalmology Center, Faculty of Medicine, Mansoura University, 24 Al-Gomhoria street, Mansoura, Egypt
| | - Amr M. El-Kannishy
- Ophthalmology Center, Faculty of Medicine, Mansoura University, 24 Al-Gomhoria street, Mansoura, Egypt
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Moussa S, Grabner G, Ruckhofer J, Dietrich M, Reitsamer H. Genetics in Keratoconus - What is New? Open Ophthalmol J 2017; 11:201-210. [PMID: 28932336 PMCID: PMC5585456 DOI: 10.2174/1874364101711010201] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 04/01/2017] [Accepted: 06/14/2017] [Indexed: 11/22/2022] Open
Abstract
Background: Keratoconus is characterized as a bilateral, progressive, non-inflammatory thinning of the cornea resulting in blurred vision due to irregular astigmatism. Keratoconus has a multifactorial etiology, with multiple genetic and environmental components contributing to the disease pathophysiology. Several genomic loci and genes have been identified that highlight the complex molecular etiology of this disease. Conclusion: The review focuses on current knowledge of these genetic risk factors associated with keratoconus.
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Affiliation(s)
- Sarah Moussa
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Günther Grabner
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Josef Ruckhofer
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Marie Dietrich
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Herbert Reitsamer
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
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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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Bikbov MM, Usubov EL, Oganisyan KK, Lobov SL, Khasanova RR, Dzhemileva LU, Khusnutdinova EK. Genetic aspects of keratoconus development. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417040020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Cruzat A, Qazi Y, Hamrah P. In Vivo Confocal Microscopy of Corneal Nerves in Health and Disease. Ocul Surf 2017; 15:15-47. [PMID: 27771327 PMCID: PMC5512932 DOI: 10.1016/j.jtos.2016.09.004] [Citation(s) in RCA: 218] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 09/19/2016] [Accepted: 09/25/2016] [Indexed: 12/20/2022]
Abstract
In vivo confocal microscopy (IVCM) is becoming an indispensable tool for studying corneal physiology and disease. Enabling the dissection of corneal architecture at a cellular level, this technique offers fast and noninvasive in vivo imaging of the cornea with images comparable to those of ex vivo histochemical techniques. Corneal nerves bear substantial relevance to clinicians and scientists alike, given their pivotal roles in regulation of corneal sensation, maintenance of epithelial integrity, as well as proliferation and promotion of wound healing. Thus, IVCM offers a unique method to study corneal nerve alterations in a myriad of conditions, such as ocular and systemic diseases and following corneal surgery, without altering the tissue microenvironment. Of particular interest has been the correlation of corneal subbasal nerves to their function, which has been studied in normal eyes, contact lens wearers, and patients with keratoconus, infectious keratitis, corneal dystrophies, and neurotrophic keratopathy. Longitudinal studies have applied IVCM to investigate the effects of corneal surgery on nerves, demonstrating their regenerative capacity. IVCM is increasingly important in the diagnosis and management of systemic conditions such as peripheral diabetic neuropathy and, more recently, in ocular diseases. In this review, we outline the principles and applications of IVCM in the study of corneal nerves in various ocular and systemic diseases.
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Affiliation(s)
- Andrea Cruzat
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Yureeda Qazi
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Pedram Hamrah
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA; Boston Image Reading Center, Tufts Medical Center, Tufts University School of Medicine, Boston, MA; Cornea Service, New England Eye Center, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA.
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Barbara R, Turnbull AMJ, Hossain P, Anderson DF, Barbara A. Epidemiology of Keratoconus. KERATOCONUS 2017. [DOI: 10.1007/978-3-319-43881-8_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Dr John Nottingham's 1854 Landmark Treatise on Conical Cornea Considered in the Context of the Current Knowledge of Keratoconus. Cornea 2016; 35:673-8. [PMID: 26989959 DOI: 10.1097/ico.0000000000000801] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
John Nottingham has been widely credited with the first accurate description of keratoconus in his treatise on conical cornea, published in 1854. Contained within the 270-page treatise are accounts and theories of keratoconus postulated by authors such as Scarpa, von Carion, von Ammon, and Mackenzie, synthesized by Nottingham in a treatise containing his own original observations. Nottingham's work delves deeply into keratoconus, with coverage reminiscent of a modern review, albeit in a far less succinct manner. He extensively describes the epidemiology, clinical presentation, underlying cause, and treatment of keratoconus. However, the concepts put forth are limited largely by the contemporary lack of understanding of the underlying anatomy and physiology of the eye, and the observations, by technological limitations. He postulates a similar treatment algorithm to that used today; optical devices being the management option of choice in the mild stages with surgery being a last resort. None of the surgical methods discussed are used in the modern era, but he does make reference to the possible efficacy of corneal transplantation. Nottingham's treatise was published over 160 years ago, yet his ideas and observations are surprisingly accurate. It is very possible that he was the first person to publish an accurate, comprehensive description of keratoconus.
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Lee A, Sakhalkar MV. Ocular manifestations of Noonan syndrome in twin siblings: a case report of keratoconus with acute corneal hydrops. Indian J Ophthalmol 2016; 62:1171-3. [PMID: 25579364 PMCID: PMC4313503 DOI: 10.4103/0301-4738.126992] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Ocular manifestations of Noonan syndrome (NS) in a set of healthy 20-year-old African-American fraternal twins are reported with emphasis on a rare finding of keratoconus with acute corneal hydrops in one twin. Both the twins had learning disabilities and attended a special needs school. Evaluation included visual acuity assessment, tonometry and external eye, slit lamp and dilated fundus examinations, topography with Pentacam and external photographs. The first case was more remarkable as keratoconus with acute corneal hydrops was observed. The patient presented with severe cloudy vision that had worsened over a span of 1 month. It improved significantly on follow-up. The second case included a unique constellation of ocular pathology that highlights the diversity of NS manifestations even amongst twins. Conservative treatment of keratoconus with acute corneal hydrops in a NS patient helped largely resolve the patient's condition. We report the diverse spectrum of ocular manifestations associated with this rare congenital disorder.
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Affiliation(s)
| | - Monali V Sakhalkar
- Department of Surgery, Mercer University School of Medicine, Middle Georgia Ophthalmology, Medical Center of Central Georgia, Macon, GA, USA
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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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