Material and methods: This retrospective and cross-sectional study included patients that underwent trabeculectomy due to primary open angle glaucoma. Patients were included in 5-fl uorouracil (5-FU) and Mitomycin C (MMC) groups according to antimetabolite drug used. Endothelial cell density (ECD), coeffi cient cell volume (CV) and percentage of hexagonal cells (HEX)at superior, central and inferior quadrants of cornea were measured using a specular microscope before and one month after the surgery.

Results: Of the 105 patients enrolled, 58were included in the 5-FU group and 47were included in the MMC group. Mean ECD, CV and percentage of HEX at all quadrants were similar between groups (p>0.05). In the 5-FU group, postoperative ECD and percentage of HEX at superior quadrant were signifi cantly lower than preoperative outcomes, while CV was signifi cantly higher (p<0.05). No signifi cant difference was observed between pre- and postoperative ECD, CV and percentage of HEX at central and inferior quadrants in the 5-FU group (p>0.05). In the MMC group, postoperative ECD and percentage of HEX at superior and central quadrants were signifi cantly lower than preoperative outcomes, while CV was signifi cantly higher (p<0.05). No signifi cant difference was observed between pre- and postoperative ECD, CV and percentage of HEX at inferior quadrant in the MMC group (p>0.05).

Conclusion: Toxic effect of the 5-FU and MMC on corneal endothelium was not homogenous and decreased with the increasing distance from drug application area. Keywords : Trabeculectomy, cornea, 5-fl uorouracil, Mitomycin C