Correlation between central corneal thickness and myopia

Purpose To analyze the correlation between central corneal thickness (CCT) and myopia in refractive surgery candidates. Materials and methods Patients that underwent myopic laser refractive surgery between January 2000 and December 2014 were included. Preoperative CCT was measured by ultrasonic pachymetry, and refractive status determined by manifest and cycloplegic refraction. Results A total of 30,245 individuals were included. Mean age was 28.2 ± 8.6 years, and 45.9% were female. Mean refractive error was 4.02 ± 2.17 D (range 0.25–19.5), and the mean CCT measurement was 533.5 ± 35.5 µm (range 404–794). Younger individuals showed higher degree of myopia ( p = 0.006). No difference in CCT was found between women and men (533.0 ± 35.1 and 533.6 ± 35.9 µm, respectively, p = 0.19). Though CCT showed no correlation with age ( p = 0.226) participants above age 40 expressed higher CCT values ( p < 0.001). No significant correlation was found between the CCT and cylinder ( p > 0.05). An increase in mean keratometry was associated with a decrease in CCT ( p < 0.001). There was a direct correlation between the degree of myopia and CCT ( r = 0.94, p < 0.001). The result remained the same after adjusting for age group and gender in stepwise backward regression analysis ( p < 0.001). Conclusion Central corneal thickness is correlated with the degree of myopia among adults undergoing refractive surgery.