Author:
Zhang Jiafan,Liu Sai,Shao Ting,Li Hua,Wang Huifeng,Long Keli
Abstract
Purpose:
To investigate the impact of corneal toricity on the distribution characteristics of corneal epithelial thickness (CET).
Methods:
A total of 330 eyes in 330 healthy participants were included in this study. They were divided into two groups based on the median of the corneal toricity value: low-toricity group (corneal toricity < 1.50 diopters) and high-toricity group (corneal toricity ≥ 1.50 diopters). The CET within a 9-mm–diameter area of the central cornea was obtained using optical coherence tomography. The difference of CET value between flat and steep meridians (F-S CET) was defined to evaluate the CET distribution. The F-S CET between the two groups was compared, and the correlations between F-S CET and the corneal toricity were analyzed.
Results:
The CET was thinner in the superior-peripheral area than in other areas. A slight intergroup difference was noted in terms of the F-S CET at the paracentral (0.11 ± 0.93 vs 0.32 ± 0.92,
P
= .038), midperipheral (0.45 ± 0.78 vs 0.77 ± 0.89,
P
= .001), and peripheral (3.11 ± 2.18 vs 4.10 ± 2.38,
P
< .001) zone. In each zone, the difference in F-S CET between the two groups was less than 1 μm. As the area expanded, the F-S CET continued to increase (
F
= 850.303,
P
< .001). A weak correlation was observed between F-S CET and corneal toricity (
r
= 0.103 to 0.240); however, this correlation was not significant in the paracentral zone. Covariance analysis demonstrated that F-S CET was slightly correlated with age, refractive state, and intraocular pressure.
Conclusions:
The corneal toricity did not significantly affect the distribution of the corneal epithelium in normal corneas.
[
J Refract Surg
. 2023;39(7):482–490.]