Changes in corneal endothelial cell density after trabeculectomy

Glaucoma is a leading cause of blindness worldwide for which trabeculectomy is the most effective surgical intervention for advanced disease. However, trabeculectomy has been associated with alterations to corneal endothelium, including a decrease in corneal endothelial cell density (CECD). The purpose of this study was to investigate changes in CECD after trabeculectomy, and identify factors contributing to cell loss, such as pre-operative biometry and lens status.

This retrospective study included 72 eyes of 60 patients who underwent trabeculectomy between January 2018 and June 2021 at two private hospitals. Demographic and clinical data were obtained at baseline. Corneal specular microscopy was performed pre-operatively and at 6 months after surgery. CECD was evaluated and compared between groups to quantify changes to corneal endothelium and identify significant factors affecting decreases in cell density.

Mean CECD was 2284.66 ± 375.59 pre-operatively and 2129.52 ± 401.96 after 6 months (p < 0.001). A greater decrease in CECD (p = 0.005) was observed in phakic eyes (235.45 ± 118.32) compared to pseudophakic eyes (137.82 ± 107.30). The amount of cell loss was negatively correlated with pre-operative central corneal thickness (p = 0.009) and anterior chamber (AC) depth (p = 0.033). There were no significant correlations between changes to CECD and patient age, gender, number of pre-operative glaucoma medications and number of post-operative antifibrotic agents.

Significant decreases in CECD occurred after trabeculectomy. Less corneal endothelial cell loss occurred in pseudophakic eyes. Hence, if patients need trabeculectomy and cataract surgery, it may be better to perform cataract surgery first. Longer term studies should derive more information.