Electrophysiological Assessment of Visual Pathways in Glaucoma

Abstract

Purpose. To assess nerve conduction in visual pathways in patients with open-angle glaucoma. Methods. Pattern-electroretinograms (PERG) and visual-evoked potentials (VEP) were simultaneously recorded in 16 patients with open-angle glaucoma (POAG) and 15 age-matched controls. The visual stimuli were checker-board patterns (the check edges subtend 15’; the contrast was 70% and reversed at the rate of 2 reversals/s). Results. POAG patients showed significantly higher PERG and VEP latencies (ANOVA: P<0.01) and significantly lower amplitudes than controls; the retinocortical time (RCT: difference between VEP P100 latency and PERG P50 latency) was longer (P<0.01) in POAG than controls and the longer RCT was correlated with the reduced PERG amplitude (r:0.798, P<0.01). Conclusions. This suggests that POAG patients have an involvement of the innermost retinal layers and impaired nerve conduction in their visual pathways.