Genetic variants in the FOXO1 and ZNF469 genes are associated with keratoconus in Sweden: a case-control study.

BACKGROUND: Keratoconus (KC) is characterized by pathological thinning and bulging of the cornea that may lead to visual impairment. The etiology of sporadic KC remains enigmatic despite intensive research in recent decades. The purpose of this study was to examine the relationship between previously highlighted genetic variants associated with KC and sporadic KC in a Swedish cohort. METHODS: A total of 176 patients (age 16-70 years) with sporadic KC diagnosed by Scheimpflug-topography (Pentacam) were included. The control group (n = 418; age 70 years) was a subsample originating from the Gothenburg H70 Birth Cohort Studies of ageing. Extraction of DNA from blood samples was performed according to standard procedures, and genotyping was performed using competitive allele specific PCR (KASP) technology. A total of 11 single nucleotide polymorphisms (SNPs) were selected for analysis. RESULTS: Statistically significant associations (p = 0.005) were found between the SNPs rs2721051 and rs9938149 and sporadic KC. These results replicate earlier research that found associations between genetic variants in the FOXO1 and BANP-ZNF469 genes and sporadic KC in other populations. CONCLUSION: Genetic variations in the FOXO1 and BANP-ZNF469 genes may be involved in the pathogenesis of sporadic KC.

Patterns in refractive error and treatment delay in keratoconus-An Australian study.

Keratoconus is the most common primary corneal ectasia and is associated with significant morbidity. In its early stages, keratoconus is often asymptomatic, making the identification of subclinical disease challenging. Refractive error is a parameter that is documented at most routine optometry visits, yet interestingly, changes in refraction of keratoconic patients over time have not yet been studied and compared with the general population. Early diagnosis of keratoconus facilitates timely referral for treatments such as corneal collagen cross-linking, which has been shown to slow disease progression. In this context, documenting delays between initial presentation to the optometrist and referral for collagen-cross-linking as well as comparing the trends in visual acuity and refractive error between keratoconic and non-keratoconic patients over time are particularly relevant.

Racial Variation in Visual Impairment of Patients With Keratoconus at Presentation.

PURPOSE: This study aimed to investigate racial disparities in the severity of keratoconus (KCN) at presentation, their intersection with socioeconomic variables, and other factors associated with visual impairment. METHODS: This retrospective cohort study examined medical records of 1989 patients (3978 treatment-naive eyes) with a diagnosis of KCN seen at Wilmer Eye Institute between 2013 and 2020. A multivariable regression model adjusting for age, sex, race, insurance type, KCN family history, atopy, smoking status, and vision correction method examined factors associated with visual impairment, defined as a best available visual acuity of worse than 20/40 in the better eye. RESULTS: Demographically, Asian patients were the youngest (33.4 ± 14.0 years) ( P < 0.001), and Black patients had the highest median area deprivation index (ADI) of 37.0 [interquartile range (IQR): 21.0-60.5] ( P < 0.001). Multivariable analysis showed a higher risk of visual impairment for Black (OR 2.25, 95% CI, 1.71-2.95) versus White patients. Medicaid (OR 2.59, 95% CI, 1.75-3.83) and Medicare (OR 2.48, 95% CI, 1.51-4.07) were also associated with a higher odds of visual impairment compared with private insurance, and active smokers were more likely to have visual impairment than those with no prior smoking history (OR 2.17, 95% CI, 1.42-3.30). Eyes of Black patients had the highest maximum keratometry (Kmax) (56.0 ± 11.0D) ( P = 0.003) and the lowest thinnest pachymetry (463.2 ± 62.5 µm) ( P = 0.006) compared with eyes of other races. CONCLUSIONS: Black race, government-funded insurance, and active smoking were significantly associated with increased odds of visual impairment in adjusted analyses. Black race was also associated with higher Kmax and lower thinnest pachymetry, suggesting that Black patients have more severe disease at presentation.

Keratoconus in India: Clinical presentation and demographic distribution based on big data analytics.

PURPOSE: This paper aims to describe the clinical presentation and demographic distribution of keratoconus (KCN) in India by analyzing the electronic medical records (EMR) of patients presenting at a multitier ophthalmology hospital network. METHODS: This cross-sectional hospital-based study included the data of 2,384,523 patients presenting between January 2012 and March 2020. Data were collected from an EMR system. Patients with a clinical diagnosis of KCN in at least one eye were included in this study. Univariate analysis was performed to identify the prevalence of KCN. A multiple logistic regression analysis was performed using R software (version 3.5.1), and the odds ratios are reported. RESULTS: Data were obtained for 14,749 (0.62%) patients with 27,703 eyes diagnosed with KCN and used for the analysis. The median age of the patients was 22 (inter-quartile range (IQR): 17-27). In total, 76.64% of adults (odds ratio = 8.77; P = <0.001) were affected the most. The majority of patients were male (61.25%), and bilateral (87.83%) affliction was the most common presentation. A significant proportion of the patients were students (63.98%). Most eyes had mild or no visual impairment (<20/70; 61.42%). Corneal signs included ectasia (41.35%), Fleischer ring (44.52%), prominent corneal nerves (45.75%), corneal scarring (13.60%), Vogts striae (18.97%), and hydrops (0.71%). Only 7.85% showed an association with allergic conjunctivitis. A contact lens clinic assessment was administered to 47.87% of patients. Overall, 10.23% of the eyes affected with KCN underwent a surgical procedure. the most common surgery was collagen cross-linking (8.05%), followed by deep anterior lamellar keratoplasty (1.13%) and penetrating keratoplasty (0.88%). CONCLUSION: KCN is usually bilateral and predominantly affects males. It commonly presents in the second and third decade of life, and only a tenth of the affected eyes require surgical treatment.

Preferred practice patterns for keratoconus: An e-survey among Indian cornea specialists.

PURPOSE: This study aimed to report practice patterns in the management of keratoconus in India. METHODS: An e-survey was conducted among members of the Cornea Society of India to assess preferred practice patterns for keratoconus. RESULTS: Of the 912 members, 234 (25.7%) completed the survey. About 88.4% worked in private eye care facilities and 76.1% in cities. Of all the respondents, 91.5% had access to a Scheimpflug-based device or an Orbscan II®; 71.4% of the respondents dispensed scleral contact lenses, and 66.7% dispensed Rose K contact lenses; 92.7% of the respondents performed corneal cross-linking (CXL); and 73.1% of the respondents performed deep anterior lamellar keratoplasty (DALK). A Scheimpflug device or Orbscan II®, Rose K or scleral contact lenses, and CXL were more readily available (P < 0.05) in private eye care facilities. The diagnostic criteria for keratoconus followed by the majority of the respondents (52.1%) were increase in corneal curvature, elevation, and thickness. An increase in keratometry values greater than 0.5 or 1.0D in a 6-month to 1-year period was considered the most favored criterion for keratoconus progression. Epithelium-off, 0.1% riboflavin solution in dextran, and accelerated protocol were the more commonly reported techniques in CXL. About 77.2% of the respondents routinely performed CXL in corneas <400 microns thick. Spectacles (91.0% of the respondents) and topography-guided photorefractive keratectomy (37.6% of the respondents) were, respectively, the preferred optical and surgical methods used to improve vision. CONCLUSION: While keratoconus management in India is comparable to other developed healthcare systems, the concentration of trained corneal surgeons in cities and private eyecare facilities may lead to less equitable distribution of treatment across the country.

Association between keratoconus and allergic conjunctivitis in children attending a Tertiary Hospital in Nigeria.

Objective: To ascertain an association between keratoconus and allergic conjunctivitis and to know if it is necessary to investigate all patients with allergic conjunctivitis for keratoconus. Methods: A hospital-based prospective study in which the eyes of children presenting with ocular allergic diseases were examined. Social demographics and clinical data were captured in a questionnaire. All the patients underwent keratometry using the autorefractor-keratometer and the pachymeter was used to measure the central corneal thickness. Data analysis was done with IBM SPSS version 28 for Windows. Frequency and chi-square were used as descriptive statistics to determine the association between dependent and independent variables. Inferential statistics using one-way ANOVA and t-test. P - Value at <0.05 was considered statistically significant. Results: 121 children with allergic conjunctivitis were reviewed. Males were 72 and females 49. The visual acuity was 6/ 6-6/ 18 in 116, and mild visual impairment - 6/ 18-6/ 60 in 5. The most common complaint was frequent itching in 109 (90.1%). Keratometry was normal in 120 (99.5%), while probable keratoconus was found by keratometry in only one patient (0.5%). Central corneal thickness was within the normal range in 33 (27.3%) children, 43 (35.5%) had thin corneas, while 45 (37.2%) had cornea thickness of more than 560 microns. Discussion: Pediatric keratoconus tends to be more aggressive than adult keratoconus with an increased risk of corneal opacities and subsequent keratoplasty. As a result of these negative impacts, early detection and prompt treatment are mandatory. Conclusion: The prevalence of keratoconus was not found to be high in this study population, but with facts emerging between the association of allergic conjunctivitis, and increased prevalence of keratoconus, it is pertinent to integrate keratoconus screening as part of the management of allergic conjunctivitis using an appropriate tool such as video keratography and slit lamp biomicroscope. Abbreviations: KC = Keratoconus, CLEK = Collaborative Longitudinal Evaluation of Keratoconus, SAC = Seasonal Allergic Conjunctivitis, PAC = Perennial Allergic Conjunctivitis, VKC = Vernal Keratoconjunctivitis, IOP = Intraocular Pressure, CCT = Central Corneal Thickness, TNF-α = Tumor Necrosis Factor-Alpha, IL = Interleukin.

The association between keratoconus and allergic eye diseases: A systematic review and meta-analysis.

BACKGROUND: To investigate the association between keratoconus (KC) and allergic eye diseases, eye rubbing, and atopy. METHODS: PubMed, Web of Science, Scopus, and Cochrane databases were searched for studies investigating eye allergy, atopy, and eye rubbing as risk factors for KC up to April 2021. Two authors independently screened all titles and abstracts against the predefined inclusion and exclusion criteria. The study analysed the prevalence of KC and its risk factors, including eye rubbing, family history of KC, atopy, and allergic eye diseases. The National Institutes of Health Study Quality Assessment Tool was used. Pooled data are presented as odds ratios (OR) and 95% confidence intervals (CI). The analysis was conducted using RevMan version 5.4 software. RESULTS: The initial search yielded 573 articles. After screening, 21 studies were identified for qualitative analysis and 15 for quantitative synthesis. A significant association was found between KC and eye rubbing (OR = 5.22, 95% CI [2.80, 9.75], p < 0.00001), family history of KC (OR = 6.67, 95% CI [4.77, 9.33], p < 0.00001), and allergies (OR = 2.21, 95% CI [1.57, 3.13], p < 0.00001). However, no significant association was found between KC and allergic eye disease (OR = 1.82, 95% CI [0.37, 8.97], p = 0.46), atopy (OR = 1.54, 95% CI [0.58, 4.09], p = 0.39), allergic rhinitis (OR = 0.85, 95% CI [0.54, 1.33], p = 0.47), smoking (OR = 0.96, 95% CI [0.76, 1.21], p = 0.73), and asthma (OR = 1.58, 95% CI [0.99, 2.53], p = 0.05). CONCLUSION: Significant associations were observed between KC and eye rubbing, family history, and allergy, but not with allergic eye disease, atopy, asthma, and allergic rhinitis.

Scleral Lens Applications Focused on Korean Patients with Various Corneal Disorders.

PURPOSE: We aimed to report on the clinical outcomes of scleral lens applications in Korean patients with various corneal disorders. METHODS: This retrospective review was conducted for 62 eyes of 47 patients who had been fitted with scleral lenses for various corneal disorders. The patients were referred for inadequate spectacle-corrected visual acuity and rigid gas permeable (RGP) or soft contact lens intolerance. Uncorrected visual acuity, habitually corrected visual acuity, best lens-corrected visual acuity, topographic indices, keratometry indices, and lens parameters were evaluated. RESULTS: Twenty-six eyes of 19 patients with keratoconus were enrolled. Other conditions included corneal scar (13 eyes of 12 patients), phlyctenules (three eyes), laceration (four eyes), chemical burn (one eye), keratitis (one eye), Peters' anomaly (one eye), fibrous dysplasia (one eye), ocular graft-versus-host disease (two eyes of one patient), irregular astigmatism (18 eyes of 12 patients), and corneal transplant status (five eyes of four patients). The mean topographic values of the eyes include flat keratometric value (43.0 ± 6.1 diopters [D]), steep keratometric value (48.0 ± 7.4 D), and astigmatism (4.9 ± 3.6 D). Of the eyes fitted with scleral lenses, best lens-corrected visual acuity (0.10 ± 0.22 logarithm of the minimum angle of resolution [logMAR]) was significantly better than the habitually corrected visual acuity (0.59 ± 0.62 logMAR, p < 0.001). CONCLUSIONS: Scleral contact lenses are a good alternative for patients with corneal abnormalities and those who are intolerable to RGP contact lenses, resulting in both successful visual outcomes and patient satisfaction, especially concerning keratoconus, corneal scar, and corneal transplant status.

Socioeconomic Correlates of Keratoconus Severity and Progression.

PURPOSE: The purpose of this study was to investigate the social determinants of health for keratoconus. METHODS: In this retrospective cohort study of patients with keratoconus, the electronic health record was reviewed for keratometry, treatments received, clinical comorbidities, and social characteristics. Outcomes included severe keratoconus at presentation (steep keratometry ≥52 diopters), disease progression (≥0.75 diopters increase from the first to the most recent clinical visit), and corneal transplantation. Logistic regression was used to evaluate factors associated with severity at presentation and corneal transplantation. Cox proportional hazards modeling was used to evaluate progression. RESULTS: A total of 1038 patients with keratoconus were identified, 725 (70%) of whom had baseline imaging. Compared with commercially insured patients, Medicaid recipients were more likely to have severe keratoconus, independent of social and clinical confounders [odds ratio (OR) 1.94, 95% confidence interval (CI), 1.12-3.35, P = 0.017]. Male sex was independently associated with progression (hazard ratio = 1.38, 95% CI, 1.03-1.84, P = 0.030). Medicare and Medicaid recipients were more likely to require transplantation compared with commercially insured patients (OR 2.71, 95% CI, 1.65-4.46, P < 0.001 and OR 1.74, 95% CI, 1.08-2.80, P = 0.022, respectively). Other social determinants of health, including non-White race/ethnicity, limited English proficiency, and unemployment, were associated with the outcomes only in univariate analysis. Obstructive sleep apnea, atopy, body mass index, and tobacco use were not associated with any outcome. CONCLUSIONS: Socioeconomic factors were more consistent predictors of keratoconus severity and corneal transplantation compared with clinical factors that have received relatively greater attention in the keratoconus literature.

Progression of keratoconus in children and adolescents.

AIMS: To evaluate the rates of keratoconus progression and associated factors in eyes of children and adolescents. METHODS: Retrospective, cohort study of individuals ≤18 years old at the time of keratoconus diagnosis and with at least 6 months of follow-up. Corneal tomography was performed using an Orbscan tomographer (Bausch & Lomb, Rochester, New York, USA) to determine whether progression occurred. Tomographic progression of keratoconus was defined as a change in any of the investigated parameters (keratometry values, KMAX, maximum anterior or posterior elevation, central pachymetry, thinnest pachymetry) beyond the limits of repeatability. RESULTS: 148 eyes of 106 patients with a mean age of 15.2±2.5 years were studied over a mean follow-up period of 2.9±2.2 years. The overall rate of tomographic progression was 77.0% (114/148 eyes). Eyes that progressed had more advanced disease at presentation with higher anterior curvature (KMAX55.4±6.3 vs 52.2±5.4 dioptres; p<0.01), posterior elevation (108.2±40.9 vs 86.3±35.6 µm; p<0.01) and lower central pachymetry measurements (442.1±56.7 vs 454.4±47.5 µm; p=0.01). Age at presentation, gender, atopy, documented eye rubbing, ethnicity and duration of follow-up were not significantly associated with progression in the multivariate analyses. There was a higher rate of bilateral progression if at least one eye had severe keratoconus (73.9%) compared with no severe keratoconus in either eye (36.8%; p=0.03). CONCLUSIONS: A high rate of progression was identified in keratoconic eyes of children and adolescents. More advanced disease at initial presentation may increase the risk of further keratoconus progression.

Comparison of accelerated corneal cross-linking for progressive keratoconus in pediatric and adult age groups: One-year results.

BACKGROUND: To compare one-year results of accelerated cross-linking (ACXL) treatment for progressive keratoconus in pediatric and adult age groups. METHODS: The records of patients who had undergone the ACXL procedure (9mV/cm2, 10min) for progressive keratoconus were evaluated retrospectively. The patients were divided into 2 groups, with the pediatric group aged 17years or less and the adult group aged 18years or more, for the statistical analysis. Pre- and 12-month post- ACXL best-corrected visual acuity (BCVA), maximum keratometry (Kmax), sim K1, sim K2, corneal thickness at the thinnest point (thCT), and corneal astigmatism (CA) values of the patient groups were recorded. RESULTS: Thirty-two right eyes of 32 patients were included in the pediatric group, and 32 right eyes of 32 patients were included in the adult group. A significant improvement in BCVA and a significant decrease in thCT values were present in both groups 12months after the surgery compared to the preoperative period. The decrease in Kmax, sim K1 and sim K2 values compared to the preoperative period was significant in the adult group. When the two groups were compared after 12months, only the simK1 value was significantly lower in the adult group, and there was no significant difference between the other measurements. CONCLUSIONS: There is a slight tendency toward more flattening in the adult group 12months after ACXL treatment, but this is not statistically significant.

Prevalence of keratoconus in refractive surgery practice population in North Macedonia.

PURPOSE: To determine the prevalence of keratoconus (KC) in relation to ethnicity in a group of people who consulted an ophthalmological care institution seeking for refractive surgery in N. Macedonia. METHODS: This was a cross-sectional, interventional retrospective study. Chart reviews were performed for all new patients attending between January 2016 and January 2020 at the Sistina Ophthalmology Hospital in Skopje. All patients were screened; KC diagnosis and classification were based on the corneal topography. Ethnicity and gender classifications were according to patients' self-opinions. RESULTS: A total of 2812 patients charts reviewed. The mean age was 31.71 years (SD ± 9.73), and 1209 (43%) were male. A total of 2050 (72.9%) declared themselves as Macedonians, 649 (23.1%) Albanians, 76 (2.7%) Turks and 37 (1.3%) in other ethnicities. Differences in age between the ethnic groups were statistically significant (x2 = 90.225, p < 0.001). KC was diagnosed in 343 patients (12.2%), while 9 (0.7%) were KC suspects and 6(0.21%) presented pellucid marginal degeneration. KC was more frequent in males (n = 246, 71.7% of total) and skewed toward younger patients. Increasing patients' age decreased the odds of KC diagnosis by 3.7% (95% CI 1.8%-4.4%) per annum. Males were four times more likely to be diagnosed with KC (AOR = 4.01; 95% CI 3.12-5.16). In comparison with Macedonian patients, Turks were more likely to be diagnosed with KC (AOR = 4.09; 95% CI 2.47-6.78). There was no difference between Macedonians and Albanians (p = 0.08). CONCLUSION: The prevalence of KC at a refractive surgery practice in N. Macedonia is much higher compared with general population (6.8/100,000) and similar to the prevalence in Middle East Asia. Nationwide screening programs are needed to diagnose the disease earlier.

Prevalence of Corneal Topographic Patterns in Ectatic Corneal Diseases.

SIGNIFICANCE: The article highlights various topographic patterns and their prevalence in a large spectrum of ectatic corneal diseases (ECDs). Knowledge of these patterns can help clinicians for quicker diagnosis and selection of appropriate contact lens design. PURPOSE: This study aimed to determine various corneal topography patterns and their prevalence in patients with ECDs who visited a tertiary eye hospital in western India. METHODS: Keratoconus, pellucid marginal degeneration, keratoglobus, and post-refractive surgery progressive corneal ectasia are considered under ECDs. This cross-sectional retrospective study reviewed records of 632 consecutive patients with clinical ECDs at their first presentation. The right eye was considered for pattern analysis. In cases with suspected or forme fruste ectasia in the right eye, the fellow eye was considered. A sagittal map with standard scale of Atlas 9000 topographer (Carl Zeiss Meditec AG, Jena, Germany) was used for pattern analysis. They were classified into 18 categories and grouped under five groups. The prevalence of these patterns was calculated and assessed with 95% confidence interval (CI). RESULTS: The mean ± SD age of patients was 23.6 ± 8.2 years. The highest prevalence was of asymmetric patterns (39.6% [95% CI, 35.7 to 43.5%]; asymmetric bowtie [AB] with steepest radial axis index [SRAX], 18.8%; AB with inferior steep, 16.0%; AB with superior steep [SS], 3.2%; symmetric bowtie with SRAX, 1.6%) and of central or paracentral patterns (28.6% [95% CI, 25.1 to 32.3%]; inferior steep, 12.2%; heart, 7.4%; oval, 4.1%; symmetric bowtie, 2.4%; round, 1.6%; irregular, 0.9%) followed by advanced patterns (17.3% [95% CI, 14.4 to 20.4%; nonmeasurable, 5.4%; globus, 4.9%; indiscriminate, 7.0%). The peripheral patterns were 11.7% (95% CI, 9.3 to 14.4%) (claw, 6.3%; junctional, 3.2%; butterfly, 1.9%; SS, 0.3%). Rare patterns were 2.8% (95% CI, 1.7 to 4.5%) (superior [junctional, claw, and heart], AB with SS with SRAX, and AB with SRAX located temporally). CONCLUSIONS: Asymmetric and central or paracentral are the most common patterns in our study. The higher prevalence of advanced patterns indicates the need for earlier diagnosis of ECDs in our population. The peripheral patterns also have significant prevalence.

Keratoconus: An updated review.

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.

Quality of life impact of eye diseases: a Save Sight Registries study.

BACKGROUND: The objectives of this study were to evaluate the quality-of-life (QoL) impact of eye diseases (keratoconus; neovascular age-related macular degeneration, AMD; retinal vein occlusion, RVO; and diabetic macular edema, DME) using the Impact of Vision Impairment (IVI) questionnaire, and to determine the relationship between the IVI scores and visual acuity. METHODS: This cross-sectional, multicentre, real-world study utilised the prospective, web-based Save Sight Registries. The IVI was completed by 1557 patients: 307 with keratoconus, 1049 with AMD, 148 with RVO and 53 with DME. Statistical analysis included Rasch analysis, Welch t-test, one-way ANOVA, Tukey's test, Pearson correlation, and multiple regression. RESULTS: The IVI scales (Overall; Visual Function, VF; Emotional, EM) had robust psychometric properties. The keratoconus patients had the worst Overall (adjusted mean: 48.2 vs. DME 58.8, RVO 64.6, AMD 67.6 units), VF (47.7 vs. DME 59.4, RVO 65.9, AMD 68.9 units) and EM (50.8 vs. DME 63.1, RVO 69.2, AMD 71.8 units) scores (all p < 0.05). The IVI scales scores weakly correlated with better and worse eye visual acuity (Pearson's r 0.24-0.39, all p < 0.05). The correlations were similar in the better eye (Overall 0.35, VF 0.39, EM 0.24) and the worse eye (Overall 0.31, VF 0.33, EM 0.25) visual acuity. Correlations with visual acuity were stronger for VF than for the EM scores. CONCLUSIONS: The IVI was a psychometrically robust QoL questionnaire. Keratoconus patients had worse IVI scores than patients with retinal diseases. The low strength of correlations between visual acuity and QoL scores, although statistically significant, suggested that a complex relationship exists.

Prevalence of Keratoconus on Screening of Egyptian LASIK Candidates: A Retrospective Multicenter Study.

PURPOSE: This is a retrospective multicenter study to report the incidental discovery of keratoconus (clinical and subclinical) in a screening of laser vision correction (LVC) surgery candidates. METHODS: This retrospective multicenter study was conducted on patients presenting for LVC in four Egyptian governorates (Cairo-Giza-6th of October-Beni Suef) during the year 2018. The patients were examined using the Pentacam HR (OCULUS Optikgeräte GmbH, Wetzlar, Germany) or Sirius (Costruzione Strumenti Oftalmici, Italy). The following parameters were evaluated: the axial curvature map, keratometry (Kmax and K2 on the posterior surface), minimum corneal thickness, anterior elevation, posterior elevation, Baiocchi-Calossi -Versaci index (Sirius), index of height decentration, and BAD-D (Pentacam). The prevalence of keratoconus cases was reported and data were analyzed. RESULTS: A total of 46 out of 782 candidates presenting for LVC in 2018 were incidentally discovered as clinical or subclinical keratoconus cases and were excluded from performing the LVC procedure. CONCLUSION: Screening of LVC candidates for keratoconus is a crucial tool to detect the incidence of the disease in the Egyptian population.

Changing Trends in Corneal Transplantation in Aotearoa/New Zealand, 1991 to 2020: Effects of Population Growth, Cataract Surgery, Endothelial Keratoplasty, and Corneal Cross-Linking for Keratoconus.

PURPOSE: The purpose of this study was to identify trends in the primary indication for keratoplasty in New Zealand/Aotearoa (NZ) after significant population growth, increase in the number of cataract surgeries per population, widespread adoption of endothelial keratoplasty, and introduction of corneal cross-linking for keratoconus. METHODS: Statistical analysis of the New Zealand National Eye Bank's prospective database of all keratoplasties was performed between January 1991 and January 2020. Indications for keratoplasty were isolated for the primary diagnosis. RESULTS: In total, 6840 corneas were transplanted with mean 236 ± 57.5 transplants/year, increasing from 2.55 to 6.06 per 100,000 NZ population/year. Over the past decade, the number of transplant recipients aged 60 years or older has increased and recipients aged 20 to 39 years have plateaued. In 2019, for the first time, regraft became the most common indication (30.9%), followed by keratoconus (27.9%) and corneal dystrophy (18.8%), with a steady decline in bullous keratopathy. Proportions of the keratoplasty technique changed dramatically: penetrating keratoplasty fell from 91.4% in 2006 to 55.0% in 2019, Descemet's stripping endothelial keratoplasty increased from 0% to 29.5%, anterior lamellar keratoplasty increased from 2.5% to 5.7%, and Descemet membrane endothelial keratoplasty increased from 0% to 9.1%. CONCLUSIONS: Keratoplasty trends in Aotearoa/NZ have changed considerably because of the evolution of phacoemulsification and keratoplasty techniques. Unlike proportions observed overseas, NZ still performs penetrating keratoplasties in over half of all transplants. Corneal cross-linking may be having an early effect of reducing keratoplasty rates for keratoconus.

[Detection of Subclinical Keratoconus]. / Detektion des subklinischen Keratokonus.

The early stage of a keratoconus (KC), without classic and characteristic clinical findings, is a contraindication for refractive surgery. This article therefore shows, in accordance with the current state of the art, ways of identifying risk factors for subclinical keratoconus.After delimitation, this publication contains a current summary of epidemiology, etiology and pathophysiology of subclinical and clinical KC. Furthermore, an overview of different grading scales is given. A detailed description of several practical possibilities for detection of subclinical KC is the focus of this publication: typical abnormalities with subclinical KC in ocular aberrometry, corneal topography, Zernike analysis, Fourier analysis, indices of the corneal anterior surface; especially tomography of the anterior segment of the eye respecting addition of the corneal posterior surface and the pachymetry, and also innovative techniques counting in the rigidity or biomechanical properties, as well as traditional techniques giving hints for subclinical KC as retinoscopy, ophthalmoscopy and subjective refraction.In preparation for refractive surgical interventions and to avoid possible consequences of subclinical KC, a suitable analysis with different methods should always be carried out in addition to a specific anamnesis. An exclusive consideration of the available indices is not sufficient, as this does not reveal early stages. Ideally, the biomechanics of the cornea is included in the diagnosis. The combination of tomography and biomechanics with methods of artificial intelligence are trendsetting in detection of subclinical KC.

Prevalence of Keratoconus and Keratoconus Suspect among Patients Seeking Refractive Surgery in Syria.

PURPOSE: The purpose of this study was to determine the prevalence of keratoconus (KC) and keratoconus suspect (KCS) among patients seeking refractive surgery in Syria. METHODS: This is a retrospective multicenter screening study. The study was conducted in Damascus University, Tishreen University, and Tartous Specialist Eye Center (a private center). Data were collected from refractive surgery candidates referred for preoperative evaluation before laser in situ keratomileusis, photorefractive keratectomy, intrastromal corneal rings, and phakic intraocular lens implantation. Corneal parameters were obtained by Scheimpflug-Placido tomography, Sirius (CSO, Italy). RESULTS: A total of 1479 patients were included in this analysis. The prevalence rates of KC and KCS were 18.19% (269/1479) and 13.52% (200/1479), respectively. In addition, patients with KC were found to have higher percentages of eye rubbing and astigmatism than suspect and normal (P < 0.0001). CONCLUSION: High prevalence rate of KC was found among patients seeking refractive surgery in Syria. Although this study was carried out on a highly selective population, it may reflect a high prevalence rate in a general population in Syria.

Progressive corneal ectatic disease in pregnancy.

Pregnancy influences ocular changes which may exacerbate existing or develop new pathology. This review summarises the existing evidence on the association between pregnancy and progressive keratoconus or iatrogenic keratectasia. Ten online databases were searched systematically. Eligible studies were published in English and reported objective ophthalmic outcomes for women with evidence of (i) a new diagnosis of keratoconus, (ii) keratoconus progression or (iii) iatrogenic keratectasia following refractive surgery; during or within one year of pregnancy. Strength of evidence was assessed using the Oxford Centre for Evidence-Based Medicine levels of evidence. Seventeen articles have reported 33 peripartum women with new-onset or progressive ectasia, evident by signs of corneal hydrops or protrusion (n = 8); steepening on topography imaging (n = 20); a mean decline in best corrected visual acuity by +0.20 logMAR (95% CI -0.01 to +0.40, n = 23); a mean increase in maximum keratometry by 2.18 D (95% CI 1.44 to 2.91, n = 42); a mean decline in spherical equivalent refraction by -1.33 D (95% CI -1.73 to -0.93, n = 41); and a mean increase in astigmatism by -1.61 D (95% CI -2.46 to -0.75, n = 19). Pregnancy is associated with progressive ectasia in some women including those with previously stable keratoconus, or a history of laser-assisted in situ keratomileusis surgery or no history of corneal ectasia. This review highlights the heterogeneity in limited existing evidence, the need for a standardised definition of ectasia progression and further prospective studies for clinical guidelines. Closely monitoring women at risk may assist in early intervention with collagen cross-linking and prevent peripartum vision loss.