Abstract
INTRODUCTION: To evaluate the corneal epithelial thickness (CET) profiles and their correlations with axial length (AL) and anterior corneal radius of curvature (Rm F) across different refractive error groups. METHODS: A total of 1225 eyes of 616 normal patients were included. CET mapping, AL, and Rm F were obtained using spectral-domain optical coherence tomography, optical biometry, and Scheimpflug corneal tomography, respectively. In the CET map, one central (2 mm), eight paracentral (2-5 mm), and eight peripheral (5-6 mm) quadrants were evaluated separately. The subjects were divided into four groups based on their refractive status: hyperopia (spherical equivalent [SE] ≥ +0.50 D), emmetropia (SE > -0.50 D and < +0.50 D), low myopia (SE ≤ -0.50 D and > -3.0 D), and moderate-high myopia (SE ≤ -3.0 D) groups. Linear mixed model analysis with Bonferroni correction was used to compare CET according to refractive error groups. The correlations between the CET profile and the AL and Rm F were analyzed. RESULTS: The central CET was 53.7 ± 3.3 μm in hyperopia (n = 34), 53.2 ± 2.9 μm in emmetropia (n = 353), 52.8 ± 2.9 μm in low myopia (n = 677), and 52.0 ± 3.1 μm in moderate-high myopia (n = 161). Although thinning was observed in CET in all quadrants from hyperopia to moderate-high myopia, it was only significant in the superior and superonasal quadrants at the 2-5 mm and 5-6 mm-diameter rings. While AL and CET were significantly positively correlated (r range 0.17-0.28) in the moderate-high myopia group, Rm F and CET were significantly positively correlated (r range 0.08-0.10) in the low and moderate-high myopia groups. CONCLUSION: CET varied according to different refractive error groups and was positively correlated with AL and Rm F, particularly in the moderate-high myopia group.