Abstract
PURPOSE: We aim to investigate the ethnic and sex differences in corneal nerves and epithelial cell metrics among healthy Chinese and Indian populations. METHODS: This cross-sectional study included 15,850 corneal nerve and 9,510 corneal epithelial cell images from 328 individuals, categorized into Chinese and Indian ethnicities. In-vivo confocal microscopy scans were performed to evaluate corneal nerves and epithelium. Quantitative analytic software was used to obtain 10 corneal nerve and epithelial parameters. RESULTS: There were 208 Chinese participants (101 males, 107 females) in this study with a mean age of 57.0 ± 15.6 years, and 120 Indian participants (58 males, 62 females) with a mean age of 55.8 ± 21.2 years (p = 0.36). Compared to Chinese participants, Indian participants exhibited significantly higher values in all nerve parameters, including corneal nerve fiber length, fiber density, branch density, total branch density, fiber area (all p < 0.001), fiber width (p = 0.041), and fiber fractal dimension (p < 0.001). Chinese participants demonstrated significantly larger epithelial size compared to their Indian counterparts (p < 0.001). Within the Chinese cohort, females presented with significantly higher corneal nerve fiber length, fiber area, and fractal dimension than males (p = 0.034, p = 0.022 and p = 0.033, respectively). Indian females showed higher epithelial cell circularity compared to Indian males (p = 0.026). CONCLUSION: Our study identifies significant ethnic and sex disparities in corneal nerves and epithelium. These should be considered when evaluating corneal metrics in Chinese and Indian populations.