Corneal Endothelial Changes in Primary Glaucoma: A Qualitative and Quantitative Evaluation by Disease Subtype and Antiglaucoma Medication Burden

Introduction Corneal endothelial cells (CECs) are critical for maintaining corneal clarity but have limited regenerative potential. Glaucoma and its treatment may compromise endothelial integrity. This study evaluated corneal endothelial changes in primary glaucoma, stratified by disease subtype and antiglaucoma medication (AGM) burden. Methods This cross-sectional study included 60 eyes of 34 patients with primary glaucoma and 60 eyes of 30 age- and sex-matched controls. Corneal endothelial parameters were assessed with a Tomey EM-4000 specular microscope. Patients were categorized as primary open-angle glaucoma (POAG) or primary angle-closure glaucoma (PACG) and further subgrouped by the number of topical AGMs. Results Glaucoma patients had lower endothelial cell density (ECD) (2325.86 ± 378.6 vs 2527.08 ± 197.05 cells/mm²; <i>P</i> < 0.001) and larger average cell size (<i>P</i> < 0.001) compared to controls. Both POAG (2405.74 ± 335.74 cells/mm²) and PACG (2177.52 ± 416.12 cells/mm²) groups had significantly reduced ECD compared to controls, with PACG showing greater loss than POAG (<i>P</i> = 0.02). ECD decreased with increasing AGM burden: 2,507.5 ± 189.89 cells/mm² (one AGM), 2460.85 ± 267.02 cells/mm² (two AGMs), and 2248 ± 383.44 cells/mm² (three AGMs) (<i>P</i> = 0.038). Conclusion Primary glaucoma is associated with significant corneal endothelial compromise, with PACG showing greater vulnerability than POAG. Increasing AGM burden correlated with further endothelial loss, suggesting possible AGM-related endothelial toxicity. Larger longitudinal studies are needed to clarify these effects.