[Retinal diseases as a cause of increased latency in the visual evoked cortical potential]

Retinal and cortical potentials to reversing checkerboard stimuli (P-ERG, P-VECP) were recorded simultaneously in ten patients with disease of the central retina and eleven patients with tumor-related optic nerve changes. While both groups exhibited comparable P100 delays in the P-VECP, delays of the q component in the P-ERG were only observed in the group with retinal disease. Thus, measurement of P-ERG and P-VECP latencies enables retinal to be distinguished from post-retinal disease in cases with visual disturbances where there are no obvious fundus changes.