Association Between Anterior Chamber Angle and Corneal Endothelial Cell Density in Chronic Angle Closure

Purpose: To study the association between corneal endothelial cell density (ECD) and degree of anterior chamber angle (ACA) opening in eyes with chronic angle closure glaucoma. Methods: The study was conducted at JEC Eye Hospitals in Indonesia. Treatment-naïve patients aged ≥ 40 years with IOP > 21 mmHg and peripheral anterior chamber depth (ACD) grade 2 or less by Van Herick’s technique were recruited. Trabecular iris angle (TIA; degree) was measured using anterior segment optical coherence tomography (AS-OCT) and classified as: grade 1 ≤ 10°, grade 2 11– 20°, and grade 3 > 20°. Noncontact specular microscopy was performed, and the following corneal parameters were obtained:ECD (cells/mm 2 ), coefficient of variation (CV; μm 2 /cell), percentage of hexagonal cells, and central corneal thickness (CCT; μm). Results: A total of 52 eyes from 52 subjects were recruited (16 grade 1 TIA, 24 grade 2 TIA, and 12 grade 3 TIA). Presenting IOP was not significantly different between groups. The median central corneal ECD was 2684.5 (1433– 2934), 2587.0 (1902– 3103), and 2441.0 (1659– 3005) cells/mm 2 in grade 1, 2, and 3 TIA, respectively, with no significant differences across the groups ( P = 0.67). The CV was lowest in grade 3 TIA (36.4 ± 7.2 μm2/cell), and highest in grade 1 TIA (38.3 ± 9.6 μm2/cell), but the differences were not significant ( P = 0.74). Likewise, the percentage of hexagonality and CCT was not significantly different. TIA was not correlated with IOP but was modestly correlated with age. Conclusion: The corneal ECD and morphological characteristics such as CV and hexagonality were not significantly different across various TIA grading in chronic angle closure. This may reflect the lack of chronic and gradual IOP insult on corneal endothelial parameters as TIA did not show direct effect towards IOP. Keywords: corneal endothelium, primary angle closure glaucoma; PACG, trabecular iris angle; TIA