Correlations between amyloid-β peptide levels in aqueous humor and retinal thickness in patients with glaucoma

Amyloid-β (Aβ) accumulation is a well-established cause of neurotoxicity in the brain and a major factor in Alzheimer's disease. However, its role in ocular neurodegeneration remains unclear. In this prospective study, we evaluated the correlation between aqueous humor Aβ concentrations and retinal nerve fiber layer (RNFL) thickness in patients with open-angle glaucoma (including primary open-angle glaucoma and normal-tension glaucoma) and exfoliation glaucoma. A total of 154 patients who underwent either cataract or glaucoma surgery were included and categorized into four groups-cataract (n = 90), glaucoma (n = 27), pseudoexfoliation syndrome (n = 21), and exfoliation glaucoma (n = 16). Aβ concentrations in aqueous humor samples collected during surgery were measured using enzyme-linked immunosorbent assay. The mean Aβ1-40 and Aβ1-42 concentrations were significantly higher in exfoliation glaucoma and pseudoexfoliation syndrome groups than those in cataract group. Aβ1-40 and Aβ1-42 concentrations were strongly and positively correlated across all groups. Aβ concentrations were negatively correlated with RNFL thickness in glaucoma and exfoliation glaucoma groups. These findings indicate a potential role for soluble Aβ peptides in the pathophysiology and progression of glaucoma.