Relationship between Central Corneal Thickness and Endothelial Cell Density in Individuals with Primary Glaucoma and the General Population Living at High Altitudes.

Purpose: To evaluate the impact of high-altitude living on central corneal thickness (CCT) and corneal endothelial cell density (ECD) in individuals diagnosed with primary glaucoma, compared to age-matched healthy controls.

Methods: This prospective study was conducted in the Lesser Himalayan region, at an average altitude between 2800 and 4200 m above sea level. The study population consisted of 120 eyes from 120 patients diagnosed with primary glaucoma who were permanent residents above 2000 meters. Subgroup 1A included individuals with primary open-angle glaucoma, whereas Subgroup 1B comprised those with angle closure glaucoma. Age-matched healthy subjects constituted the control group (Group 2).

Results: Individuals with glaucoma residing above 3800 m exhibited a mean CCT reduction of 11 ± 5.3 μm and a mean ECD decrease of 145 ± 22 cells/mm² compared to those living below 3800 m. Participants with primary glaucoma had lower CCT and ECD than healthy controls. In healthy controls (Group 2), there was a nonsignificant increase in CCT (P = 0.090) and nonsignificant reductions in ECD (P = 0.076) and hexagonality (P = 0.080) at altitudes above 3800 m. At altitudes above 3800 meters, Subgroups 1A and IB had significantly lower ECD, greater coefficient of variation, and reduced hexagonality (all P < 0.001) than those below 3800 m. A significant inverse correlation between ECD and age was found in Subgroup 1A (P = 0.008), Subgroup 1B (P < 0.001), and Group 2 (P = 0.001).

Conclusions: High-altitude residence may exacerbate corneal changes in patients with primary glaucoma, with potential implications for disease progression and management. The findings highlight the need for altitude-specific considerations in glaucoma assessment and treatment and underscore the importance of regular corneal evaluation in these populations.