Abstract
Purpose :
To characterize patterns of corneal epithelial thickness distribution in normal eyes, and compare them to those of keratoconus eyes.
Methods :
157 normal control eyes and 27 keratoconus (KC) eyes were imaged with an anterior segment OCT device. Their corneal epithelial thickness maps and data were extracted and analyzed. As given by the device, the 9mm epithelial thickness maps were divided into 25 regions: central 2mm region, 5mm, 7mm, and 9mm superior (S), inferior (I), temporal (T), nasal (N), superiotemporal (ST), superionasal (SN), inferiotemporal (IT), and inferionasal (IN) regions. The average epithelial thickness in each region, as well as differences in epithelial thickness between regions, was determined and compared between normal and KC eyes. The correlation between corneal astigmatism and epithelial thickness parameters was also determined.
Results :
Average epithelial thickness in the central 9mm of the cornea was 53.96mm and 53.39mm in normal and KC eyes, respectively (p=0.66). Min, max, range and standard deviation of epithelial thickness were significantly different between normal and KC (49.35mm vs 41.62mm, 58.83mm vs 64.42mm, 9.49mm vs 22.80mm, and 1.91mm and 5.36mm, respectively; p<0.001). The 5mm inferior and inferotemporal regions were significantly different between normal and KC (p<0.001). Also in the 5mm zone, differences between superior and inferior regions (p<0.001), superionasal and inferiotemporal regions (p=0.009), and superiotemporal and inferionasal regions (p=0.003) were significantly different between normal and KC eyes. There was no correlation between epithelial thickness parameters and corneal astigmatism (-0.48<r2<0.46).
Conclusions :
The corneal epithelial thickness profile differs between normal and KC eyes. KC eyes have greater variability in corneal epithelial thickness distribution. The corneal epithelium does not remodel to regularize corneal astigmatism.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.