A cross-sectional study to determine the normal corneal epithelial thickness in Indian population using 9-mm wide optical coherence tomography scans

PURPOSE: To study the corneal epithelial thickness with 9-mm scans of optical coherence tomography in normal Indians with appropriate representation of all age groups. METHODS: This was a cross-sectional observational study. 263 patients were divided into the age groups 5–20 years, 21–35 years, 36–50 years and more than 51 years were recruited for the study. All patients underwent a detailed ophthalmic examination. Patients found to have any ocular surface or intraocular disease condition (except cataract and refractive error), or who had undergone any ophthalmic surgery in the past, or had corneal topography changes suggestive of corneal ectasias (screened in patients with astigmatism more than 3 diopters) or had been continuously using any topical medication in either eye for a period of 3 months or more with the last instillation being within 1 month of inclusion in the study were excluded. All subjects underwent corneal epithelial thickness measurement with anterior segment optical coherence tomography (AS-OCT) on the Avanti OCT (Model RTVueXR1002, Optovue, USA). The corneal epithelial thickness (CET) data from 25 sectors in each eye were analyzed. RESULTS: 263 right and left eyes of 263 patients were analyzed in the study. Mean CETs in the central 2 mm zone were 54.13 ± 4.51 μm and 54.37 ± 3.75 μm for the right and left eyes, respectively. The superior peripheral sectors and inferior paracentral sectors were the thinnest and the thickest sectors, respectively, in both eyes. CONCLUSION: CET parameters for Indian eyes are comparable to those reported from racially distinct and geographically distant study subjects.