ORIGINAL RESEARCH article
Front. Med.
Sec. Ophthalmology
Ethnic and Sex Differences in Corneal Nerves and Corneal Epithelial Cells in Healthy Population
Provisionally accepted
Fengyi Liu1
Chang Liu2
Mingyi Yu2
Isabelle Lee2Hassan Mansoor3Ching-Yu Cheng4,5Wajid Ali Khan3Jodhbir S Mehta2,4,6
Yu-Chi Liu2,4,6,7*- 1School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- 2Regenerative Therapy Group, Singapore Eye Research Institute (SERI), Singapore, Singapore
- 3Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan
- 4Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
- 5Epidemiology Group, Singapore Eye Research Institute (SERI), Singapore, Singapore
- 6Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore, Singapore
- 7Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
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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). Conclusions: 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.
Keywords: Corneal nerve1, corneal epithelial cel2, ethnicity3, sex4, in-vivo confocal microscopy5
Received: 11 May 2025; Accepted: 27 Oct 2025.
Copyright: © 2025 Liu, Liu, Yu, Lee, Mansoor, Cheng, Khan, Mehta and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yu-Chi Liu, liuchiy@gmail.com
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