Purpose: To evaluate the safety and efficacy of real-time measurement of corneal epithelial thickness and investigate the distribution characteristics in a large normal-eye population using a clinically available spectral-domain anterior-segment optical coherence tomography (AS OCT) system.
Methods: Corneal epithelial thickness distribution and topographic thickness variability were clinically investigated using AS OCT imaging in 373 patients with normal, healthy eyes. Descriptive statistics investigated 3 sets of subgroups, male (n = 171) and female (n = 202), younger (n = 194) and older (n = 179), right eyes (n = 195) and left eyes (n = 197).
Results: Pupil center epithelial thickness repeatability was an average 0.88 ± 0.71 μm; a similar repeatability was noted for the superior, inferior, maximum, and minimum epithelial thickness. On average, the pupil center epithelial thickness was 53.28 ± 3.34 μm, superior 51.86 ± 3.78 μm, inferior 53.81 ± 3.44 μm, minimum 48.65 ± 4.54 μm, maximum 56.35 ± 3.80 μm, and topographic variability was 1.78 ± 0.78 μm. Small differences were noted between male (average center 54.10 ± 3.34 μm) and female (52.58 ± 3.19 μm) subjects. The topographic thickness variability seems to increase with age: younger group, 1.65 ± 0.83 μm; older group, 1.93 ± 0.90 μm (P = 0.173).
Conclusions: We present a comprehensive investigation of corneal epithelial thickness distribution characteristics in a healthy, untreated human eye population by using in vivo, clinically available Fourier-domain AS OCT. The 3-dimensional epithelial maps reveal epithelial nonuniformity and provide a novel benchmark for future and comparative studies.