Effects of Smoking on Central Corneal Thickness and the Corneal Endothelial Cell Layer in Otherwise Healthy Subjects

The effects of smoking on central corneal thickness (CCT), corneal endothelial cell density (ECD), and morphology were evaluated in otherwise healthy subjects.

The study included 103 current smokers and 106 healthy nonsmoking subjects without any eye disease apart from refractive errors. Endothelial cell density, percentage of hexagonality, and coefficient of variation (CV) in cell size were measured using noncontact specular microscopy. Central corneal thickness was measured by ultrasound pachymetry.

The mean age of participants in the nonsmoker group was 31.4 ± 5.1 years (18-60) and 33.0±9.1 years (18-58) in the current smoker group. The mean CCT value was 523.7±34 μm in the nonsmoker group and 518.5±37 μm in the smoker group. The mean ECD, CV, and percentage of hexagonality values were 2,881±293.7 cells per square millimeter, 32.5±6%, and 56.6±11% in the nonsmoker group, and 2,681±323.9 cells per square millimeter, 33.4±5%, and 55.5±10% in the smoker group, respectively. Although there was no difference between the groups in terms of CCT, CV, and percentage of hexagonality values, a significant difference was determined in the case of ECD values[ZERO WIDTH SPACE][ZERO WIDTH SPACE] (P<0.001). The smoker group comprised 67 light smokers (65.0%) and 36 (35.0%) heavy smokers. Between these groups, there was no statistically significant difference in the mean values of CCT, ECD, CV, and the percentage of hexagonality.

Although cigarette smoking has no effect on cell polymorphism and polymegethism, the results suggest that smoking reduces endothelial cell count.