Risk Of Keratoconus Research Articles

Screening Preadolescents for Keratoconus Risk Factors in a Low-Resource Setting.

Diagnosis of keratoconus (KC) involves the identification of corneal signs, refraction, and corneal imaging. The prevalence of KC ranges between 0.4 per 100,000 and 4,790, depending on geographical location and ethnicity. Diagnosis of KC should occur early for appropriate management with relatively affordable, accessible options to prevent visual impairment in low-income settings. Written consent and assent were obtained from subjects before a questionnaire was administered to collate demographics, general and ocular history of subjects, and keratoconus risk factors. A novel scoring system was applied to identify subjects at a higher risk of developing KC and document KC risk factors prevalent in Harare using an informed risk score calculation. Thousand one hundred fifty-three subjects aged between 6 and 12 years were seen. The prevalence of KC was found to be 626/100,000 in primary school children resident in Harare. Reduced visual acuity, vernal keratoconjunctivitis, itchy eyes, eye rubbing, and atopy are the most prevalent KC risk factors identified in this community. Informed risk score calculation proved valuable in the screening for KC. The prevalence of KC in primary school children in Harare is 626/100,000, which is relatively high. School-aged children stand to benefit from the early screening for KC based on evidence-based practices in the absence of advanced clinical instrumentation.

Inflammation and keratoconus: A comprehensive bidirectional Mendelian randomization analysis.

An increasing body of evidence supports the involvement of inflammation and immune responses in the occurrence and development of keratoconus (KC). However, the causal relationship between inflammatory factors and KC remains unclear. We employed a 2-way Mendelian randomization (MR) approach to investigate the interaction between KC and inflammatory factors. Instrumental variables for 41 circulating inflammatory regulators and 12 matrix metalloproteinases (MMPs) were selected from genome-wide association studies of European ancestry. Summary statistics for KC were obtained from a genome-wide association study comprising 2116 cases and 24,626 controls of European ancestry. The primary analytical method for assessing causality was the inverse-variance weighted method. Two additional MR methods (MR-Egger and weighted median) were employed to complement the inverse-variance weighted results. In addition, several sensitivity analyses were conducted to evaluate heterogeneity, horizontal pleiotropy, and stability. Our findings indicated that genetically predicted higher levels of macrophage inflammatory protein-1β (odds ratio = 1.126, 95% confidence interval: 1.029-1.232, P = .01) and MMP-13 (odds ratio = 1.211, 95% confidence interval: 1.070-1.371, P = .003) were positively associated with an elevated risk of KC. Conversely, genetically predicted KC was associated with increased levels of interferon-gamma, interleukin-4, and MMP-1. Our current study provided suggestive evidence supporting causal associations of macrophage inflammatory protein-1β and MMP-13 with the risk of KC. In addition, KC appeared to affect the expression of interferon-gamma, interleukin-4, and MMP-1.

AvaGen Genetic Testing versus Ocular Screening Assessments Including the Keratoconus Severity Score (KSS) and Randleman Ectasia Risk Score System (ERSS) in Refractive Surgery Candidates.

To determine whether the AvaGen (AG) Genetic Eye Test provided additional information for screening for the presence of keratoconus (KC) and assessing KC risk in refractive surgery candidates, as compared to the Keratoconus Severity Score (KSS) and Randleman Ectasia Risk Score System (ERSS). This retrospective study analyzed patients seeking refractive surgery at an eye clinic in the United States between January 2022 and July 2023. The inclusion criteria encompassed those with a family history of KC, positive KC indices, or both. Corneal evaluations and demographic information were recorded and analyzed. KSS and ERSS criteria were utilized to evaluate postoperative KC and ectasia risk, respectively. Patients were categorized on how the AG genetic test compared to KSS and ERSS criteria. Clinicians assessed topographic indices, criteria scoring, and AG testing to deliver a definitive surgical recommendation. Among the 19 patients evaluated for ectasia risk, AG testing showed lower KC risk than ocular screening in three patients (15.8%), equal risk in three patients (15.8%), and higher risk in 13 patients (68.4%). The mean AG scores were 45.7 ± 7.0, 49.0 ± 3.46, and 61 ± 13.0 for these respective categories. The most frequently identified KC risk genes were ADAMTS18, COL2A1, and COL4A1. The AG test modified the physician's recommendation for refractive surgery in nine cases (47.4%). Despite the promising application of AG testing for assessing KC risk, further research and development are needed to enhance its applicability for screening refractive surgery candidates, in addition to standard ocular screening approaches.

Causal Links Between Systemic Disorders and Keratoconus in European Population

PurposeThe objective of this study was to establish the presence of a causal linkage between prevalent systemic diseases and keratoconus (KC). DesignMendelian randomization (MR) analysis. MethodsAfter an exhaustive screening process, genetic variants linked to various systemic diseases were identified as instrumental variables at the genome-wide significance level. Subsequently, MR analyses were conducted to elucidate their potential causal connection with KC (N = 26,742). The encompassed systemic ailments comprise diabetes, hay fever/allergic rhinitis/eczema, obstructive sleep apnea, thyroid dysfunction, aortic aneurysm, major depressive disorder, inflammatory bowel disease (including Crohn's disease and ulcerative colitis), and mitral valve prolapse. Our study adheres to the principles of Strengthening the Reporting of Observational Studies in Epidemiology Using Mendelian Randomization guidelines. ResultsUsing inverse variance weighting as the primary MR analysis method, our findings revealed that hay fever/allergic rhinitis/eczema (odds ratio, 10.144; 95% CI, 2.441 - 42.149; P = 0.001) and ulcerative colitis (odds ratio, 1.147; 95% CI, 1.054 - 1.248; P = 0.002) were associated with an increased risk of KC within the largest population under scrutiny. Conversely, the prolonged hyperglycemic state did not exhibit a potentially protective effect in delaying the pathogenesis of KC, and no correlation was observed between the two (odds ratio, 0.320; 95% CI, 0.029 - 3.549; P = 0.353). Also, obstructive sleep apnea, thyroid function, aortic aneurysm, major depressive disorder, Crohn's disease, and mitral valve prolapse did not exhibit a causal association with KC (P > 0.05 for all comparisons). ConclusionsThis study indicates an increased risk of KC related to hay fever/allergic rhinitis/eczema and ulcerative colitis, with diabetes not providing a protective effect. These findings may potentially contribute some insights to inform clinical interventions.

Alterations in Corneal Sensitivity, Staining and Biomechanics of Alopecia Areata Patients: Novel Findings in a Case-Control Study.

Background: A higher prevalence of ophthalmological alterations in systemic inflammatory diseases has been demonstrated. Objectives: Our objectives were to determine anterior segment findings and corneal properties in alopecia areata (AA). Methods: This is a case-control study. Severe AA patients (Severity of Alopecia Tool > 50%) and non-AA subjects underwent a general ophthalmological examination, a Pentacam and Corvis scheimpflug technology examination (Oculus Optikgeräte GmbH, Wetzlar, Germany). Visual acuity, refractive error, corneal aesthesiometry, and biomechanical and topographic variables were registered. Results: In total, 25 AA patients (50 eyes; 50.6 ± 8.1 years) and 29 controls (58 eyes; 49.4 ± 8.6 years) were included. AA patients had decreased corneal sensitivity, more corneal staining, and a more advanced cataract (p ≤ 0.004). The anterior topographic flat meridian, mean anterior keratometry, and maximum keratometric point were increased in AA (p ≤ 0.040), while pachymetry values were thinner (p ≤ 0.001). Keratoconus index and Belin/Ambrosio-enhanced ectasia total deviation display were increased (p ≤ 0.007). Two eyes with a topographic diagnosis of keratoconus and four eyes with subclinical keratoconus were detected in AA. Applanation lengths were smaller in AA (p ≤ 0.029). The Corvis Biomechanical Index was increased in AA (p = 0.022). Conclusions: AA patients have reduced corneal sensitivity and increased corneal staining. Topographic and biomechanical parameters are altered, and there could be a higher risk of keratoconus, thus possibly requiring routine ophthalmological examination.

Mendelian Randomisation Analysis of Causal Association between Lifestyle, Health Factors, and Keratoconus.

Keratoconus (KC), a leading cause of vision impairment, has an unclear aetiology. This study used Mendelian randomization (MR) to explore the causal links between various factors (smoking, asthma, Down syndrome, inflammatory bowel disease, atopic dermatitis, and serum 25-hydroxyvitamin D levels) and KC. A two-sample MR design, grounded in genome-wide association study (GWAS) summary statistics, was adopted using data from FinnGen, UK Biobank, and other GWAS-related articles. The inverse-variance weighted (IVW) method was employed, complemented by the Wald ratio method for factors with only one single-nucleotide polymorphism (SNP). Sensitivity and stability were assessed through Cochrane's Q test, the MR-Egger intercept test, MR-PRESSO outlier test, and the leave-one-out analysis. The IVW results for the ORA (Ocular Response Analyzer) biomechanical parameters indicated significant associations between tobacco smoking (CH: p < 0.001; CRF: p = 0.009) and inflammatory bowel disease (CH: p = 0.032; CRF: p = 0.001) and corneal biomechanics. The Wald ratio method showed tobacco smoking was associated with a lower risk of KC (p = 0.024). Conversely, asthma (p = 0.009), atopic dermatitis (p = 0.012), inflammatory bowel disease (p = 0.017), and serum 25-hydroxyvitamin D levels (p = 0.039) were associated with a higher risk of KC by IVW, and the same applied to Down syndrome (p = 0.004) using the Wald ratio. These results underscore the role of corneal biomechanics as potential mediators in KC risk, warranting further investigation using Corvis ST and Brillouin microscopy. The findings emphasise the importance of timely screening for specific populations in KC prevention and management.

Impact of a 50bp insertion/deletion polymorphism of the superoxide dismutase-1 on oxidative stress status and risk of keratoconus

Keratoconus (KC) is characterized by the predominant primary ectatic disease, affecting the cornea, necessitating corneal transplants in some cases. While some loci associated with KC risk have been identified, the understanding of the disease remains limited. Superoxide dismutase (SOD) enzymes play a crucial role in countering the reactive oxygen species and providing protection against oxidative stress (OS). Accordingly, the objective of this study was to investigate a potential association of a 50 nucleotide base pairs (bp) insertion/deletion (I/D) within the SOD1 promoter, and the located 1684 bp upstream of the SOD1 ATG, with KC in the Iranian population. Additionally, an assessment was conducted on SOD activity and the total antioxidant capacity (TAC), as determined by the ferric reducing-antioxidant power assay, along with malondialdehyde (MDA) levels. In this case-control study, genomic DNA was extracted from the blood cells of KC (n = 402) and healthy (n = 331) individuals. The genotype of this gene was determined using the PCR technique. Furthermore, the amount of SOD enzyme activity and the MDA and TAC levels were measured in the serum of the study groups. The (I/I) genotype was present in 84.23%, the (I/D) genotype in 15.06%, and the (D/D) genotype in 0.69% of both groups. A statistically significant relationship was seen between different genotypes and TAC, MDA, and SOD1 activity indices (P < 0.05). Individuals with the D/D genotype exhibited a decrease in total antioxidant capacity, an increase in the amount of MDA, and a decrease in SOD1 enzyme activity (P < 0.05). Moreover, the logistic regression analysis of KC development indicated that elevated levels of MDA increased the risk of KC incidence in the patient group compared to the healthy group, while a higher activity of SOD1 and greater values of TAC decreased the KC risk. The removal of the 50 bp fragment reduced SOD1 activity and elevated OS levels, thereby impacting the oxidant-antioxidant balance. This could potentially play a significant role in individuals afflicted by KC.

Association between Polymorphism rs61876744 in PNPLA2 Gene and Keratoconus in a Saudi Cohort.

The genetic etiology of Keratoconus (KC) in Middle Eastern Arabs of Saudi origin is still unclear. A recent genome-wide study identified two significant loci in the region of PNPLA2 (rs61876744) and CSNK1E (rs138380) for KC that may be associated with KC in the Saudi population. In addition, polymorphisms in the apolipoprotein E (APOE) gene, namely, rs429358 and rs7412, responsible for APOE allelic variants ε2, ε3, and ε4, may influence KC via oxidative stress mechanism(s). Thus, we investigated the possible association of polymorphisms rs61876744, rs138380, rs429358, rs7412, and APOE genotypes in KC patients of the Saudi population. This study included 98 KC cases and 167 controls. Polymorphisms rs6187644 and rs138380 were genotyped using TaqMan assays, and rs429358 and rs7412 were genotyped via Sanger sequencing. Although the allele frequency of rs61876744(T) in PNPLA2 was a protective effect against KC (odds ratio (OR) = 0.64, 95% confidence interval (CI) = 0.44-0.93), the p-value (p = 0.020) was not significant for multiple testing correction (p = 0.05/4 = 0.015). However, rs6187644 genotype showed a modestly significant protective effect in the dominant model (OR = 0.53, 95% CI = 0.32-0.88, p = 0.013). Polymorphisms rs138380, rs429358, and rs7412 showed no significant allelic or genotype association with KC. However, the ε2-carriers (ε2/ε2 and ε2/ε3 genotypes) exhibited a greater than 5-fold increased risk of KC, albeit non-significantly (p = 0.055). Regression analysis showed no significant effect of age, gender, and the four polymorphisms on KC. Our results suggest that polymorphism rs6187644 in PNPLA2 might be associated with KC in the Middle Eastern Arabs of Saudi origin but warrant a large-scale association analysis at this locus.

Psychiatric Comorbidities Associated With Keratoconus

Evaluating risk factors for keratoconus, often associated with recurrent eye rubbing, could generate hypotheses to be tested in future interventional trials. To assess the risk for keratoconus associated with psychiatric comorbidities in adolescents and adults. This population-based cross-sectional study included medical records of Israeli adolescents and adults in military service from January 2011 through December 2021. The prevalence of anxiety, obsessive compulsive disorder (OCD), autism, and attention-deficit/hyperactivity disorder (ADHD) was evaluated in individuals with and without keratoconus. The association between keratoconus and psychiatric comorbidities was tested using univariate and multivariant analyses. Overall, 940 763 adolescents and adults were included. Mean (SD) age was 17.56 (1.47) years, and 59.3% were male. Keratoconus was documented in 1533 individuals, with a prevalence of 0.16%. Patients with keratoconus were more likely to be diagnosed with ADHD compared with the general population (odds ratio [OR], 1.58; 95% CI, 1.38-1.81; P < .001). After adjusting for age, sex, intellectual status, height, and weight, the results remained unchanged (hazard ratio, 1.46; 95% CI, 1.27-1.67; P < .001). Stratification according to age showed an association between keratoconus and ADHD for males (OR, 1.62; 95% CI, 1.39-1.90; P < .001) but not for females (OR, 1.29; 95% CI, 0.96-1.74; P = .09). In a large cohort of adolescents and adults, ADHD was associated with a diagnosis of keratoconus in male patients, even after adjusting for possible confounders. Although a causative effect could not be ascribed, these findings support further investigation into the potential value of education regarding eye rubbing in this population.

Causal relationships between type 2 diabetes, glycemic traits and keratoconus.

The relationship between diabetes mellitus and keratoconus remains controversial. This study aimed to assess the potential causal relationships among type 2 diabetes, glycemic traits, and the risk of keratoconus. We used a two-sample Mendelian randomization (MR) design based on genome-wide association summary statistics. Fasting glucose, proinsulin levels, adiponectin, hemoglobin A1c (HbA1c) and type 2 diabetes with and without body mass index (BMI) adjustment were used as exposures and keratoconus was used as the outcome. MR analysis was performed using the inverse-variance weighted method, MR-Egger regression method, weighted-mode method, weighted median method and the MR-pleiotropy residual sum and outlier test (PRESSO). Results showed that genetically predicted lower fasting glucose were significantly associated with a higher risk of keratoconus [IVW: odds ratio (OR) = 0.382; 95% confidence interval (CI) = 0.261-0.560; p = 8.162 × 10-7]. Genetically predicted lower proinsulin levels were potentially linked to a higher risk of keratoconus (IVW: OR = 0.739; 95% CI = 0.568-0.963; p = 0.025). In addition, genetically predicted type 2 diabetes negatively correlated with keratoconus (IVW: BMI-unadjusted: OR = 0.869; 95% CI = 0.775-0.974, p = 0.016; BMI-adjusted: OR = 0.880, 95% CI = 0.789-0.982, p = 0.022). These associations were further corroborated by the evidence from all sensitivity analyses. These findings provide genetic evidence that higher fasting glucose levels are associated with a lower risk of keratoconus. However, further studies are required to confirmed this hypothesis and to understand the mechanisms underlying this putative causative relationship.

Assessment of Keratoconus Risk in Very Asymmetric Ectasia Using Corneal Tomographic and Biomechanical Parameters.

To investigate the relationship between corneal tomographic or biomechanical parameters and risk of keratoconus in very asymmetric ectasia (VAE). This retrospective case-control single-centre study included patients with VAE and normal controls. The VAE group had clinical ectasia in one eye and normal topography (VAE-NT) in the fellow eye; VAE-NT eyes were selected for analysis. The control group was selected from corneal refractive surgery candidates; the right eye was enrolled. Scheimpflug-based corneal tomography (Pentacam) and corneal biomechanical assessment (Corvis ST) were performed. Univariate and multivariable logistic regression were performed using Cox proportional hazards models to evaluate keratoconus-associated risk factors. A two-piecewise linear regression model was applied to examine the threshold effect of selected vital paragmeters on the risk of keratoconus according to a smoothing plot. Threshold effect between tomographic integration and risk of keratoconus was observed. Discrepancy between the central corneal thickness and thinnest corneal thickness (discrepancy CCT vs TCT) greater than 5 μm, discrepancy between the apex corneal thickness and thinnest corneal thickness (discrepancy ACT vs TCT) greater than 3 μm, vector distance between CCT and TCT (distance CCT vs TCT) greater than 0.65 mm indicated a significant increased risk of keratoconus. Risk of keratoconus decreased when distance CCT vs TCT was less than 0.65 mm. Discrepancy CCT vs TCT, discrepancy ACT vs TCT, and distance CCT vs TCT can be used as indicators for risk assessment of early keratoconus.

A high body mass index strengthens the association between the time of eye rubbing and keratoconus in a Chinese population: a case control study

BackgroundAlthough body mass index (BMI) and eye rubbing are linked to an increased risk of keratoconus (KC), the interactive effect of eye rubbing and BMI on KC is largely unknown. This study aimed to evaluate the independent and interactive effects of BMI and eye rubbing on KC and to further explore the role of environmental factors on the occurrence of KC.MethodsA total of 621 individuals (291 KC patients and 330 control individuals) were enrolled in this hospital‑based study on KC patients in Central China after individuals missing BMI data were excluded. BMI was calculated as weight in kilograms divided by the square of height in meters. Data on eye rubbing was recorded through face-to-face interviews. Generalized linear regression models were used to analyze associations among BMI, eye rubbing and KC. Interaction plots were used to describe the interactive effects of BMI and eye rubbing on KC.ResultsThe β and 95% confidence interval (CI) were 0.923 (0.112, 1.733) (p = 0.026) and 3.356 (1.953, 4.759) (p < 0.001), respectively, for the effect of each 10 kg/m2 increase in BMI and each 1 min increase in eye rubbing on KC. The interaction of BMI and eye rubbing were positively correlated with KC (p < 0.001).ConclusionThese findings suggested that a high BMI aggravated the negative effect of eye rubbing on KC, implying that individuals with a high BMI may be more susceptible to exposure to eye rubbing, which is related to an increased risk of KC.

Awareness of Keratoconus and Its Association With Eye Rubbing Among the Population in Aseer Province.

Keratoconus (KC), is a non-inflammatory, bilateral, asymmetrical, progressive disease characterized by ectasia, thinning, increasing corneal curvature, and loss of visual acuity. In Saudi Arabia, it was discovered that KC has been the main reason for corneal transplantation in the past 20 years. Eye rubbing is considered one of the most significant risk factors for KC based on available data. A cross-sectional study was conducted among adults in Aseer province, Saudi Arabia in 2023.Data were collected through a pre-designed online questionnaire consisting of 17 questions divided into three sections. The questionnaire was preceded by informed consent and insured to maintain the confidentiality of the data. A total of 498 respondents were included in this study. The majority of the study's participants were in the 18 to 25 age group and females made up the majority.The majority of participants had a university education. 41.6% of individuals reported experiencing an allergic disorder, 59.0% reported having knowledge about KC, and the overall participants' awareness regarding KC was poor at 85.74%, with the highest percentage of good awareness (22.2%) detected among the 18-25 age group. The study revealed a concerning lack of awareness about KC among the population in Aseer Province, Saudi Arabia. Additionally, a significant percentage of participants engaged in eye rubbing, a behavior associated with increased risk for KC. There is a need for increased awareness about KC and the importance of avoiding eye rubbing.

Association of 2 Lysyl Oxidase Gene Single Nucleotide Polymorphisms with Keratoconus: A Nationwide Registration Study.

Keratoconus (KC) is the most common primary ectatic corneal disease, characterized by progressive thinning of the cornea, affecting its shape and structure and leading to visual loss. Lysyl oxidase is an important component of the extracellular matrix and contributes to the homeostasis of corneal stromal extracellular matrix via enzymatic reaction. This nationwide registration study aims to examine the association of KC with 2 known single nucleotide polymorphisms, rs2956540 and rs10519694, in a population of Iranian descent. Case-control. One hundred seventy-eight subjects with KC and 180 clinically healthy subjects participated in the study. Genomic DNA was extracted from peripheral blood samples, and their genotypes were determined using tetra-primer amplification refractory mutation system-polymerase chain reaction. Allele frequency for rs2956540 and rs10519694. Genotype frequency was significantly different between cases and controls for rs2956540 (P value=0.019). The rs2956540 C allele carriers were significantly more frequent among KC cases than healthy controls (P valuechi-square=0.015, P valueFisher exact=0.017). There was a significant difference in genotype frequency between groups for rs10519694 (P value=0.001). T allele carriers were significantly more frequent among KC patients (P valuechi-square=0.002, P valueFisher exact=0.001). Sex stratification revealed no significant differences in genotype frequency between males and females in cases and controls. Fitting the general linear model showed that rs10519694 could be considered a predictor for the development of KC (P value=0.001); however, this was not observed for rs2956540 (P value=0.323). rs2956540 and rs10519694 are associated with KC in a population of Iranian descent. rs10519694 could potentially be used for KC risk prediction.

Ocular manifestations of children with atopic dermatitis in Saudi Arabia.

To examine the incidence of ocular abnormalities in children with atopic dermatitis (AD) in Saudi Arabia and its association with the severity of AD. This is a cross-sectional study on 50 children with AD who were between 5 and 16 years of age. The severity of AD was evaluated using the SCORing Atopic Dermatitis (SCORAD) index. All the children underwent slit lamp exams, visual acuity assessment, intraocular pressure measurement, and corneal topography. The children were considered to have an ophthalmic abnormality if one or more of the following signs were present: glaucoma, keratoconus suspicion, in addition to lid, conjunctival, corneal, lenticular, or retinal abnormalities. Based on the SCORAD severity index, 14% of children had mild AD (7/50), 38% had moderate AD (19/50), and nearly half had severe AD. More than half the children exhibited facial involvement, and half had peri-orbital signs. The mean SCORAD index was 35.75. The mean age was 10.48±3.6y, and the cohort showed a slight male predominance (54% males). Both eyes of the 50 children in the cohort were studied. Based on the ocular examinations, 92% of the patients showed ocular abnormalities: lid abnormalities (27/50) followed by keratitis (22/50). Four patients had moderate risk for keratoconus in one eye and eight patients were suspected to have keratoconus. However, SCORAD severity index was not associated with age, sex, or the number or presence of ophthalmic abnormalities. This is the first study in Saudi Arabia to evaluate the prevalence of ocular manifestations in children with AD. The results indicate that the majority of children with AD have ocular abnormalities that mainly include lid abnormalities. Based on these findings, larger scale studies are needed to affirm whether regular screening for ophthalmic abnormalities would be beneficial for children with AD in terms of early intervention and prevention of sight-threatening complications.

Prevalence and risk factors of keratoconus (including oxidative stress biomarkers) in a cohort study of Shiraz university of medical science employees in Iran

BackgroundTo determine the prevalence of keratoconus in Shiraz University of Medical Sciences Employees and the related risk factors including oxidative stress biomarkers.Methods2546 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.ResultsThe 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.ConclusionsKeratoconus 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.

Colombian Ocular Diseases Epidemiology Study (CODES): incidence and sociodemographic characterisation of keratoconus between 2015 and 2020

ObjectiveTo estimate the incidence and describe the demographic characteristics of keratoconus (KC) in Colombia using national health registry data between January 1st 2015 and December 31th 2020.Methods and analysisWe conducted...

Risk Profile of Keratoconus among Secondary School Students in the West Region of Cameroon.

This study determined the risk factors of keratoconus (KC) among secondary school students in the West Region of Cameroon. A stratified, random sampling technique was used to select the 3015 secondary school students, 8 years and older, within the West Region of Cameroon. Selected school students completed the validated Keratoconus Risk Investigative Survey (KRIS) and a structured demographic questionnaire to determine the risk profile of KC. Descriptive analysis, logistic regression and p-values were used to provide an overview of the demographic findings and the risk factors of KC. Estimates were made as the proportion of affected school students and presented with a 95% confidence interval (CI). Multivariate logistic regression analysis was performed to explore the association between KC and the independent predictors that were found significant in the univariate analysis. The ages of the majority (93.2%) of students ranged from eight years to 18 years (mean = 13.18 ± years) and were mostly female (59.7%). Gender (OR 2.024, p < 0.001), eye rubbing (OR 3.615, p < 0.001), exposure to sunlight (OR 2.735, p < 0.001), blood relations with KC (OR 41.819, p < 0.001) and allergic experience (OR 1.070, p < 0.001) were considered. Eye rubbing was the most significant risk factor of keratoconus followed by refractive error, allergic experiences and sunlight exposure. These findings support the evidence that the etiology of KC is multifactorial, with eye rubbing being the most significant factor in this cohort. There is a need to address eye rubbing among students to minimize the risk of KC. Furthermore, 34.46% of students in Cameroon were at risk of developing KC. Hence the risk profile is that one engages in eye rubbing, has a family member with KC, spends more than eight hours per week in the sun and is prone to allergies. It will therefore be prudent for these risk factors for keratoconus to be included in the school health education programs.

New Keratoconus Risk Factors: A Cross-Sectional Case-Control Study.

Purpose To evaluate risk factors associated with keratoconus in a monocentric cross-sectional case-control study. Methods This observational study occurred from June 2019 to February 2021 in a university hospital (France). The case group consisted of 195 patients with keratoconus in at least one eye who were followed up by a corneal specialist. The control group consisted of 195 patients without any evidence of keratoconus on slit-lamp examination and corneal topography, who were matched 1 : 1 to controls by age and sex. Data were collected by a self-completed paper questionnaire before the consultation, and a multivariate logistic regression was performed. Results Multivariate analysis revealed significant associations of keratoconus with family history (odds ratio [OR] = 22.2, p < 0.001), rubbing eyes (OR = 10.9, p < 0.001), allergy (any kind) (OR = 3.80, p < 0.001), smoking exposure (OR = 2.08, p=0.017), and dry eyes (OR = 1.77, p=0.045f). The worst eye was associated with the more rubbed eye (p < 0.001) and the more pressed eye during the night according to sleeping position (p < 0.041). Conclusion This study confirmed the association between keratoconus and eye rubbing, family history, and allergy. It highlighted the role of pressure on the eyes during sleep. Other less known risk factors such as dry eyes and smoking exposure should be explored in future studies.

Association of Novel Loci With Keratoconus Susceptibility in a Multitrait Genome-Wide Association Study of the UK Biobank Database and Canadian Longitudinal Study on Aging

Keratoconus can be a debilitating corneal ectasia in which the cornea thins, bulges, and steepens into a conical shape. Early features of keratoconus include myopia and irregular astigmatism, which affect vision and can be treated with contact lenses, collagen cross-linking, or, in advanced cases, corneal transplant. Recent estimates of the prevalence of keratoconus based on results of Scheimpflug imaging in young adults are as high as 1.2%. However, obtaining very large keratoconus data sets for a genome-wide association study (GWAS) is problematic because few population studies include Scheimpflug imaging and because severe keratoconus is relatively rare. To identify novel keratoconus loci using corneal resistance factor (CRF) and central corneal thickness (CCT). This multitrait GWAS used European ancestry CRF data from UK Biobank (UKB) (n = 105 427) and the Canadian Longitudinal Study on Aging (CLSA) (n = 18 307) and European ancestry CCT data from the International Glaucoma Genetics Consortium (IGGC) (n = 17 803). The CRF and CCT variants in published keratoconus data sets (4669 cases and 116 547 controls) were compared. The data set from UKB was compiled March 24, 2020; data were released from the CLSA in July 2020; and IGGC data were available from May 1, 2018. Association of CRF and CCT variants with keratoconus risk. The GWAS included 4 cohorts: 105 427 UKB European ancestry (56 134 women [53.2%] and 49 293 men [46.7%]; mean [SD] age, 57 [8] years), 5029 UKB South Asian ancestry (2368 women [47.1%] and 2661 men [52.9%]; mean [SD] age, 54 [8] years), 902 UKB East Asian ancestry (622 women [68.9%] and 280 men [31.0%]; mean [SD] age, 53 [8] years), and 18 307 CLSA European ancestry (9260 women [50.6%] and 9047 men [49.4%]; mean [SD] age, 63 [10] years) participants. A total of 369 CRF and 233 CCT loci were identified, including 36 novel CRF loci and 114 novel CCT loci. Twenty-nine CRF loci and 24 CCT loci were associated with keratoconus. Polygenic risk scores (PRS) were constructed using CRF- and CCT-associated variants and published keratoconus variants. The PRS result showed that adding a CRF- or CCT-based PRS to the keratoconus PRS from previously published variants improved the prediction area under the receiver operating characteristic curve (from 0.705 to 0.756 for CRF and from 0.715 to 0.755 for CCT). These findings support the use of multitrait modeling of corneal parameters in a relatively large data set to identify new keratoconus risk loci and enhance polygenic risk score models.