Prevalence and Associated Factors of Keratoconus in Jerusalem: A Cross-sectional Study

Purpose: To determine the prevalence and associated factors for keratoconus in a college student population sample in Jerusalem. Methods: Volunteers participated in this cross-sectional study. Videokeratography was performed on both eyes of each subject who also completed an anonymous questionnaire. Keratoconus was defined by cone apex >= a parts per thousand yen 50D, inferior-superior dioptric difference >= a parts per thousand yen 3.5 diopters, as well as positive results from the software indices KISA, KCI and KSI. The association between independent predictors and keratoconus was analyzed using multivariate logistic regression analysis. Results: Of a total of 987 volunteers, 981 (mean age 24.4) were included. The prevalence of keratoconus among all subjects was 2.34% (95% confidence interval [CI] 1.4--3.3). It was significantly higher in men (4.91%, CI 2.6--7.3) than women (1.07%, CI 0.3--1.9) but not between Israeli Arabs (3.0%, CI 0.6--5.4) and Israeli Jews (2.2%, CI 1.2--3.3). Keratoconus was significantly associated with positive family history of the disease (Odds Ratio [OR] 17.1, CI 5.0--57.8, P < 0.001), male gender (OR 5.4, CI 2.1--14.3, P == 0.001) and atopy (OR 3.0, CI 1.2--7.6, P == 0.02), but not with eye rubbing. Conclusions: The prevalence of keratoconus in Jerusalem was found to be much higher than that seen in other parts of the world, except India. This may be related to a combination of genetic and environmental factors. Positive family history, male gender and atopy were shown to be significant predictors. The results of this study signal a need for public health outreach and intervention for keratoconus.