Essential role of ultraviolet radiation in the decrease of corneal endothelial cell density caused by pterygium.

Purpose: To investigate the essential role of ultraviolet (UV) radiation in the decrease of corneal endothelial cell density (ECD) caused by pterygium.
Methods: In this retrospective controlled study, 76 consecutive patients with unilateral primary pterygium were enrolled from January 2016 to August 2016. The Central corneal ECD was measured in both eyes. Divide the subjects into two subgroups according to the UV exposure time, and the difference of corneal ECD between both eyes was analyzed using independent samples t-test. The relationship between the percentage of difference of corneal ECD and the disease duration, the percentage of pterygium to the cornea and the astigmatism value were analyzed.
Results: For subjects with longer UV exposure, the average of ECD in pterygium group and control group were, respectively, 2264.83 ± 349.78 cells/mm ² and 2477.16 ± 300.36 cells/mm ² (P = 0.004). For subjects with short UV exposure, the average of ECD in pterygium group and control group were, respectively, 2596.46 ± 373.24 cells/mm ² and 2690.66 ± 321.34 cells/mm ² (P = 0.262). The decrease of corneal ECD was positively correlated with the period of the disease (P = 0.035). There was no statistical correlation between a decrease in the corneal ECD and the percentage of pterygium to cornea (R = -0.055, P = 0.635) and the astigmatism value in the pterygium eye (R = -0.135, P = 0.246).
Conclusions: UV radiation exposure played a significant role in the effect of pterygium decreasing the corneal ECD.