Pediatric keratoconus epidemiology: a systematic scoping review.

BACKGROUND: Pediatric keratoconus (pediatric KC) causes progressive deformation of the cornea in children and adolescents, leading to a gradual loss of vision and a need for rehabilitation. However, new treatments may halt the disease and prevent worse outcomes that require penetrating keratoplasty and its associated morbidity and high cost, irreversible loss of vision, and amblyopia. Few systematic reviews focus on keratoconus-and even fewer, on pediatric KC. METHODS: Here, we report a systematic scoping review of pediatric KC epidemiology and discuss the studies reporting data on pediatric KC. We used PRISMA-ScR methodology and checklists in the elaboration of the manuscript. The inclusion criteria were: English language; publication between August 7, 1998, and August 7, 2019 (20 years); theme of the study pediatric KC epidemiology. The search strategy: searches of the PubMed-MEDLINE database and Cochrane Database of Systematic Reviews, using eight combinations of the following MeSH terms: keratoconus; child; incidence; prevalence; pediatrics; adolescent; epidemiology. RESULTS: We charted and reviewed the selected articles. Initial searches included 1802 records; after the exclusion of article duplicates, we screened 777 records, read 97 articles in full text, and included 76 articles in this review. CONCLUSIONS: Recent epidemiological studies with better methodologies demonstrated increased prevalence rates in comparison to the older literature. This effect may be due to better diagnostic methods and better sample selection than those in historical studies. Diagnosis remains a major challenge as the early disease is usually asymptomatic. Economic and social aspects of pediatric KC remain understudied in the pediatric literature. Global, inclusive, and proactive screening studies in schools are imperative to better understand the great impact of this disease in the young.

Prevalence of Keratoconus Based on Scheimpflug Corneal Tomography Metrics in a Pediatric Population From a Chicago-Based School Age Vision Clinic.

PURPOSE: Determine the pediatric prevalence of keratoconus (KC) using Scheimpflug corneal tomography. METHODS: A prospective observational study was done on subjects aged 3 to 18 years at the Princeton Vision Clinic, Chicago, IL. Scheimpflug tomography (Pentacam HR, OCULUS Optikgerate GmbH) scans (Belin/Ambrósio Enhanced Ectasia BAD3) yielded BAD Final D (Final D) and Back Elevation at the Thinnest Point (BETP) measurements. Criteria differentiating non-KC from KC suspects & KC were, Non-KC -Final D <2.00 in both eyes; KC suspect -Final D ≥2.00 and <3.00 in combination with BETP ≥18 µm for myopia and ≥28 µm for hyperopia/mixed astigmatism in at least one eye; and KC -Final D of ≥3.00 with BETP ≥18 µm for myopia or ≥28 µm for hyperopia/mixed astigmatism in at least one eye. Two thousand two hundred and six subjects were recorded, removing duplicate and poor-quality scans leaving 2007 subjects. RESULTS: Of 2007 subjects, six were classified as KC -prevalence of 1:334, three subjects were KC suspects -prevalence of 1:669, and total prevalence of KC suspects and KC was 1:223. CONCLUSION: The prevalence of KC in children is higher than previously reported, emphasizing the importance of sensitive screening for KC at its earliest manifestation as standard in pediatric comprehensive eye examinations.

Prevalence of Keratoconus Among High School Students in Southern Brazil: A Community-Based Study.

OBJECTIVES: This study aimed to determine the prevalence of keratoconus (KC) in teenagers who live in Southern Brazil and detect any possible associated factors. METHODS: This prospective, observational, mobile clinic-based cross-sectional study collected data from students between 14 and 21 years from seven high schools who were living in the Greater Porto Alegre metropolitan region in Southern Brazil. Subjects were clinically surveyed and examined using a slitlamp and rotational Scheimpflug corneal tomography system. All data were collected at the mobile clinic during a single visit. RESULTS: Eight-hundred twenty-six students were evaluated (357 boys and 469 girls) with an average age of 16.7±1.2 years. Six subjects were classified as having KC (four girls), yielding a prevalence rate of 0.73% (95% confidence interval, 0.27%-1.57%) or one per 137 teenagers in Southern Brazil. Logistic regression showed an association between KC and positive history of eye rubbing ( P =0.02). CONCLUSION: According to our investigation, this is the first KC prevalence study in South America using the latest technologies (Scheimpflug imaging). The prevalence of KC among teenagers in Southern Brazil is within the highest reported worldwide. We also found an association between KC and history of eye rubbing. Keratoconus is not an uncommon disorder in our population, and the efforts to identify the disease and reduce its risk factors in an earlier phase are justified.

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.

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.

Assessment of Health Disparities and Barriers to Accessing Keratoconus and Crosslinking at a Tertiary Referral Center.

PURPOSE: The aim of this study was to determine the barriers to accessing the crosslinking service in Auckland, New Zealand. METHODS: This was a prospective 1-year study of patients at Auckland District Health Board. Studied parameters included age, sex, body mass index, ethnicity, New Zealand Deprivation (NZDep; an area-based measure of socioeconomic status, 1 = low deprivation-10 = high deprivation) score of residence, disease severity (maximum keratometry and thinnest corneal thickness), attendance, distance travelled, car ownership, employment status, and visual outcomes. Statistical analysis was performed using independent t tests, Pearson correlation, independent samples ANOVA, MANCOVA, and binomial logistic regression. RESULTS: Four hundred fifty-four patients with keratoconus were analyzed and had a mean age of 24.1 ± 0.8 years, mean body mass index of 33.0 ± 9.7 kg/m 2 , and 43% were female. Pacific Peoples consisted 40.2% of the population; Maori 27.2%; Europeans 21.2%; Asian 9.9%; and Middle Eastern, Latin American, and African (MELAA) 1.3%. The mean distance travelled was 12.5 ± 9.5 km, NZDep score was 6.8 ± 2.6, and attendance was 69.0 ± 42.5%. The lowest attendance was observed in Pacific Peoples (58.9%) and the highest was in Asians (90%) ( P = 0.019). The mean worst-eye visual acuity at attendance was 0.75 ± 0.47 logMAR (6/35). Unemployment was associated with worse best-eye visual acuity at FSA ( P = 0.01) and follow-up ( P < 0.05). Maori and Pacific Peoples had the highest NZDep ( P < 0.001), were younger at presentation ( P = 0.019), had higher disease severity ( P < 0.001), and worse visual acuity ( P < 0.001). CONCLUSIONS: Poor attendance was seen in this cohort. Pacific Peoples and Maori presented younger with worse disease severity and visual acuity but also had the highest nonattendance. These results suggest that deprivation, factors associated with ethnicity, and unemployment are potential barriers to attendance.

Prevalence and Economic Burden of Keratoconus in the United States.

PURPOSE: To assess the prevalence and economic burden of keratoconus in the United States. DESIGN: Retrospective cohort study. METHODS: Patients enrolled in Medicaid and Children's Health Insurance Program (CHIP) who were diagnosed with keratoconus between 2016 and 2019 were included. The data reported to the Centers for Disease Control and Prevention (CDC) Vision and Eye Health Surveillance System (VEHSS) were analyzed. The crude prevalence rates (national and statewise) were obtained from the database and extrapolated to estimate the keratoconus case count in the United States. The keratoconus prevalence was compared between male and female individuals using the Mann-Whitney test, whereas Brown-Forsythe 1-way analysis of variance was used to compare prevalence between age and racial groups. The Dunnett T3 multiple comparison test was used for intergroup comparison. Finally, the economic burden of keratoconus was assessed by inflation-adjusted direct costs to patients and total cases in the country. RESULTS: In the cohort of 69,502,000 patients enrolled for Medicaid and CHIP, the national prevalence of keratoconus was computed to be 0.04% in 2019 and had increased from 0.03% in 2016. The highest prevalence of keratoconus was observed in patients 18 to 39 years of age, followed by patients 40 to 64 years of age; comparable prevalence rates were observed in these age groups in the Black population. The prevalence was moderately higher in female compared to male individuals; however, significantly higher keratoconus prevalence was observed in Black female individuals compared to male individuals. A significantly high prevalence of keratoconus was observed in the Black population, followed by Hispanic population. In 2019, the average inflation-adjusted lifetime cost of keratoconus treatment was USD 28,766.69, with a cumulative economic burden of USD 3.8 billion. CONCLUSIONS: In the United States, keratoconus is most prevalent in individuals 18 to 39 years of age. The keratoconus prevalence is higher in the Black population, specifically female individuals, and the diagnosis is often delayed in these patients.

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.

Keratoconus in Down syndrome: Prevalence, risk factors, severity and corneal tomographic characteristics.

BACKGROUND: This study investigated the prevalence, risk factors and severity of corneal tomographic features of keratoconus in Down syndrome (DS). Additionally, previous studies indicate anomalous corneal features in DS, without keratoconus, this study characterised corneal features in DS without keratoconus. METHODS: This prospective observational study included participants with DS ≥10 years old. Keratoconus diagnosis, risk factors and corneal tomographic characteristics were recorded. Participants underwent slit-lamp biomicroscopy, Scheimpflug corneal tomography, corneal topography and autorefraction. A diagnosis of keratoconus (DS-KC), suspect keratoconus (DS-SK) and non-keratoconus (DS-NK) was made based on expert review of scans by three fellowship trained anterior segment ophthalmologists. Corneal tomography parameters from one eye of each participant were analysed. RESULTS: Keratoconus affected 50 (26.3%) of 190 participants, diagnosed by corneal tomography, topography or slit-lamp signs. Corneal hydrops affected 14.0% of DS-KC participants. Eye rubbing was a significant risk factor for keratoconus (p = 0.036). 175 (92%) participants could undertake corneal tomography of which tomography assessment alone identified 47 (26.9%) DS-KC participants, 64 (36.6%) DS-SK participants and 64 (36.6%) DS-NK participants. Significant differences (p < 0.001) were identified when the DS-KC, DS-SK and DS-NK groups were compared in maximum keratometry and posterior elevation at the thinnest point respectively: median (interquartile range) 50.20 (10.30D), 47.60 (1.95D), 46.50 (2.40D); 24.0 (38.00 µm), 10.00 (13.75 µm), 8.00 (6.00 µm). The DS-SK and DS-NK cohorts had similar minimum pachymetry, however, had several significantly different parameters among which included greater maximum keratometry, posterior elevation at the thinnest point in the DS-SK group. CONCLUSIONS: Keratoconus is common in DS. Keratoconus screening with corneal tomography is recommended for early detection.

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.

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.

Prevalence and Associations of Keratoconus Among Children, Adults, and Elderly in the Population-Based Ural Eye Studies.

PURPOSE: To estimate prevalence and associations of keratoconus in populations in Russia with an age from childhood to seniority. METHODS: The study population consisted of the cohorts of 3 population-based studies performed in urban and rural areas within the same geographical region in Bashkortostan/Russia: the Ural Children Eye Study (UCES; age = 6-18 y; n = 4890), the Ural Eye and Medical Study (UEMS; age = >40 y; n = 5314), and the Ural Very Old Study (UVOS; age = >85 y; n = 651). Based on Scheimflug imaging, keratoconus was defined by a keratometric reading of ≥48 diopters (D) in any eye. RESULTS: The mean maximal and minimal corneal refractive power increased from the UCES (43.58 ± 1.50 D and 42.70 ± 1.42 D, respectively) to the UEMS (44.26 ± 1.70 D and 43.61 ± 1.76 D, respectively) and to the UVOS (45.1 ± 1.72 D and 43.98 ± 1.68 D, respectively). Correspondingly, keratoconus prevalence increased from the UCES (42/4890; 0.086%; 95% CI = 0.060, 0.112) to the UEMS (112/5314; 2.11%; 95% CI = 1.72, 2.49) and to the UVOS (42/651; 6.45%; 95% CI = 4.56, 8.34). In the UCES, higher keratoconus prevalence was associated (multivariable analysis) with higher birth order [odds ratio (OR) = 2.34; 95% CI = 1.32, 4.15; P = 0.004], lower birth weight (OR = 0.99; 95% CI = 0.99, 0.99; P < 0.001), and shorter axial length (OR = 0.15; 95% CI = 0.08, 0.30; P < 0.001). In the UEMS, keratoconus prevalence correlated with shorter axial length (OR = 0.15; 95% CI = 0.10, 0.23; P < 0.001), larger corneal volume (OR = 1.17; 95% CI = 1.09, 1.25; P = 0.001), thicker lens (OR = 2.27; 95% CI = 1.06, 5.28; P = 0.04), cortical cataract degree (OR = 1.02; 95% CI = 1.01, 1.04; P = 0.01), and higher stage of age-related macular degeneration (OR = 1.65; 95% CI = 1.09, 2.51; P = 0.02). In the UVOS, keratoconus prevalence correlated with lower educational level (OR = 0.84; 95% CI = 0.71, 0.99; P = 0.04) and lower dynamometric handgrip force (OR = 0.92; 95% CI = 0.88, 0.97; P = 0.003). CONCLUSIONS: In this study on multiethnic groups from Russia, keratoconus prevalence increased from the pediatric group (0.09%) to the adult group (2.11%) and seniority group (6.45%), correlated mostly with biometric ocular parameters and was in all age groups statistically independent of most systemic parameters.

Psychiatric Comorbidities Associated With Keratoconus.

Importance: Evaluating risk factors for keratoconus, often associated with recurrent eye rubbing, could generate hypotheses to be tested in future interventional trials. Objective: To assess the risk for keratoconus associated with psychiatric comorbidities in adolescents and adults. Design, Setting, and Participants: This population-based cross-sectional study included medical records of Israeli adolescents and adults in military service from January 2011 through December 2021. Main Outcomes and Measures: 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. Results: 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). Conclusions and Relevance: 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.

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

BACKGROUND: Although 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. METHODS: A total of 621 individuals (291 KC patients and 330 control individuals) were enrolled in this hospital­based 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. RESULTS: The ß 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). CONCLUSION: These 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.

Prevailing practice patterns in keratoconus among Indian ophthalmologists.

Objective: The past few years have seen a rapid advancement in the management of keratoconus (KC). However, there is no prescribed standard of care for the management of KC. This study evaluated the prevailing practice patterns among Indian ophthalmologists in the diagnosis and treatment of KC via an online survey. Methods: This was a survey-based cross-sectional study in which a questionnaire (Supplement 1) was created. Questions pertaining to the practicing experience, setting of practice, and training background were asked in addition to the investigations done and decision making in KC management. Responses were collected via Survey Monkey (Survey Monkey, Palo Alto, California, USA) and statistical analysis performed using R software (4.1.3). Results: The survey was answered by 273 ophthalmologists. Pentacam was the most used topographer (195 users), followed by Orbscan (41 users), Sirius (34 users), and Galilei (3 users). The lowest limit of pachymetry for performing collagen crosslinking (CXL) was 400µ for most practitioners. More than half the respondents (50.55%) did not perform photorefractive keratectomy (PRK) or intracorneal ring segment (ICRS) implantation in a suitable patient. Accelerated 10-minute protocol (9 mW/cm2 for 10 minutes) was the most commonly (54.21%) used for CXL, followed by Dresden protocol (3 mW/cm2 for 30 minutes) (36.63%). When a patient was unsuitable for CXL, 55.31% surgeons advise contact lens (CL) trial, 35.16% surgeons advise keratoplasty, 26.74% surgeons perform stromal augmentation, and 7.69% surgeons advise spectacle correction. Corneal scar was the most common indication (49.45%) for performing keratoplasty. Conclusion: Topography remains the most used diagnostic modality for initial diagnosis. Optical coherence tomography and epithelial mapping are increasingly being used for early diagnosis of KC. Not all ophthalmologists were comfortable performing ICRS or PRK. When patients are unsuitable for CXL, CL trial remains the most frequently advised option followed by keratoplasty.

Late-onset distal-apical intracorneal ring-segments keratopathy: an analysis of a large sample in a multicenter study.

PURPOSE: To review the prevalence and describe the characteristics, of cases with late-onset intracorneal ring segments (ICRS) keratopathy in a multicenter study. METHODS: A retrospective multicentric case-series study was performed in a specialized keratoconus service, from Buenos Aires, Argentina. An electronic clinical chart from patients with ICRS keratopathy between January 1999 and January 2019 was reviewed. We included cases with late-onset distal-apical ICRS keratopathy, which was defined as a persistent corneal lesion developed 12 months or later after implantation, located over, around, or closer to the ICRS. All the surgeries were performed by a manual corneal tunnel creation technique. Samples were taken to rule out infectious etiology. RESULTS: From 5217 eyes that underwent ICRS implantation, 13 cases (0.24%) were detected. The keratopathy onset was 72 ± 42.98 months (29-133) after ICRS implantation. Cultures were negative in all cases. An ICRS exchange was made for five cases in stage I and four in stage II. Four cases presented with partial ICRS extrusion in stage III. ICRS exchange was possible in two of them and a penetration keratoplasty was necessary for the rest. All cases remained stable 1 year after surgical procedures. CONCLUSIONS: A late-onset distal-apical ICRS keratopathy was detected with low prevalence (0.24%) in a large sample. It was classified into three stages according to its severity. Different treatments were selected for each stage, obtaining stable results 1 year after treatment.

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.