How are macular changes reflected in pattern visually evoked cortical potentials?

To investigate the macular contribution to the amplitude and latency of pattern visual evoked cortical potentials (PVECPs), we recorded PVECPs in patients with unilateral macular disease (retinal diseases involving the macular region) and optic neuritis. We selected patients with visual acuities better than 0.3, which is thought to be the minimum acuity to provide clearly discernible responses. The visual stimulus was a checkerboard. We varied the check size in 4 steps as 7, 14, 28, and 56 min of arc, and the contrast was 20% or 80%. The amplitude of the sinusoidal wave of steady-state VECPs (12 Hz) and the P100 component of a transient VECP (3 Hz) were measured. Significant attenuation and delay of PVECPs in the affected eye were found in the macular disease group. Macular disease may cause an increase of VECP latency. However, VECP seemed to be a more sensitive test of optic nerve disease than of macular disease, when patients had similar visual acuities.