Reference values of the central corneal thickness with different refractive errors for the adult Egyptian population
Background: To generate reference values of the central corneal thickness (CCT) with different refractive errors for the adult Egyptian population. Methods: A retrospective, observational, and cross-sectional study of 2200 eyes in 1166 subjects scheduled for LASIK, who came to private refractive eye center, Ismailia, Egypt. The study period was from January 2018 to January 2020. The subjects were divided into a broad range of myopia with spherical equivalent (SE) <-0.5D and hyperopia SE> +0.5D.
... yperopia SE> +0.5D. Then, the myopic eyes divided into low (SE>-3.0D), moderate (SE-3.0D to >-6.0D), and high (SE<-6.0D). Similarly, the hyperopic eyes were divided into low (SE<+3.0 D) and moderate (SE+3.0D to <+6.0D) and high >+6.0D. The refractive error was measured by an auto-refractometer (Topcon, Tokyo Optical Co., Ltd., Japan), and CCT was measured using Sirius (CSO, Florence, Italy). Results: The data of 1100 myopic eyes in 556 subjects (30.5% males and 69.5% females) and 1100 hyperopic eyes in 610 subjects (33.6% males and 66.4% females). The mean+SD of CCT for the total myopic subjects was 531.98+32.92μm, range (406 to 636μm). The mean+SD of SE was -4.1±2.5D, range (-0.5 to -12.0D). The mean+SD of CCT for the total hyperopic subjects was 529±38.8μm, range (448 to 619 μm). The mean+SD of SE was +3.65+1.97D, range (+0.5 to +8.5D).Conclusion: In this study, the mean of CCT of the Egyptian population was 531.9 μm for myopic and 529μm for hyperopic subjects respectively. The myopic and hyperopic subjects show a reduction in CCT with age. Females have a thinner cornea than males, 23.6% of the myopic eyes, and 16.5% of the hyperopic eyes have CCT less than 500μm.