Assessment of visual function before and after macular surgery by pattern visual evoked cortical potentials

PURPOSE: To investigate pre- and postoperative visual function in patients with macular hole and those with epiretinal macular membrane (ERM) by means of visual evoked cortical potential (VECP). MATERIAL AND METHODS: VECP was recorded from 15 eyes with macular hole and 9 eyes with ERM prior to and 3 months after surgical treatment. Check sizes of 30' for transient stimulation, and 7.5', 15', 30', 60' and 120' for steady-state stimulation were applied. RESULTS: In transient VECPs, the P 100 component was prolonged and attenuated in both diseases before surgery, and it remained unchanged after surgery. In the eyes with macular hole, the amplitudes of steady-state VECPs showed significant reduction in 15' and 30' check sizes before surgery, and recovered only in 15' check size after surgery. The preoperative spatial frequency curve of ERM was lowered in the whole frequency range measured. CONCLUSIONS: VECP reflected the area of macular hole and ERM. VECP changes after surgery were considered to depend on the degree of surgical invasion.