Electrophysiological assessment of visual pathways in glaucoma

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.