Differential expression of neurofilament light chain and glial fibrillary acidic protein in aqueous humor and plasma among patients with primary open-angle glaucoma

To evaluate the expression differences of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in the aqueous humor (AH) and plasma of patients with primary open-angle glaucoma (POAG), and to compare them with the intensity of disease progression. A total of 38 POAG patients and 62 cataract patients were recruited as controls. The ultra-sensitive single-molecule array (SIMOA) technique was used to detect the concentrations of NfL and GFAP in the plasma and aqueous humor samples of the subjects. AH NfL was markedly elevated in POAG compared to controls ( p = 0.003), whereas plasma NfL showed only a non-significant numerical increase ( p = 0.127). GFAP levels remained unchanged in both compartments. Neither marker correlated with glaucoma severity. This exploratory study demonstrates compartment-specific elevation of NfL in POAG, supporting its potential as a candidate biomarker for RGC axonal injury. No robust GFAP alterations were detected in this cohort, suggesting differential capacity of the two proteins to reflect POAG pathology. but conclusions are limited by the cross-sectional design and modest sample size; larger validation is needed to define its clinical value.