Effects of Mitomycin C on Corneal Endothelial Cell Counts in Pterygium Surgery: Role of Application Location

Purpose To evaluate changes in corneal endothelial cell counts after pterygium surgery with application of mitomycin C (MMC) either on the perilimbal sclera or in the subconjunctival space. Design Prospective, randomized interventional study. Methods Fifty-six eyes of 56 patients with primary pterygium underwent excision followed by removal of subconjunctival fibrovascular tissue, 0.02% MMC application, and amniotic membrane transplantation. These were stratified randomly into 2 groups. In 1 group (n = 28), MMC was applied on the perilimbal bare sclera (sclera group), and in other group (n = 28), MMC was applied under conjunctiva, where subconjunctival fibrovascular tissue was removed (subconjunctiva group). Based on severity of pterygium fleshiness, MMC was used for 1, 3, or 5 minutes in 8, 13, and 7 eyes, respectively, in the sclera group and in 9, 13, and 6 eyes, respectively, in the subconjunctiva group. Central corneal endothelial cell counts were evaluated before and during 6 months of follow-up after surgery. Results Mean preoperative endothelial cell count was 2810 ± 278 cells/mm 2 in the sclera group and 2857 ± 332 cells/mm 2 in the subconjunctiva group. Mean endothelial cell losses in sclera and subconjunctiva groups were 9.7% and 9.0% at 1 week, 6.5% and 6.5% at 1 month, 4.0% and 5.0% at 3 months, and 3.4% and 4.8% at 6 months, respectively, with no statistically significant difference between the 2 groups. Longer durations of MMC application were associated with significantly greater endothelial losses in both groups. Conclusions Regardless of application location, MMC use during pterygium surgery can cause a significant decrease in central endothelial cell count.