[Electrically evoked responses in patients with macular holes]

The Electrically Evoked Response (EER) was analyzed in 7 patients with macular holes in order to determine whether EER reflects macular function. The EER was recorded from an occipital electrode (Oz) by applying a constant electric current of 1.0 mA with a duration of 5 msec and frequency of 1.85 Hz. In five patients with unilateral complete break of macula, each amplitude for the P2 component from the affected eyes was significantly smaller than that from contralateral eyes. However there was no such difference in both eyes of two patients with bilateral macular holes. No significant difference was shown in the amplitude for the P1 and P3 components of EER. These results strongly suggest that the retinal origin of P2 may mainly be in the macular area and that analysis of P2 might be useful to determine further clinical applications of EER.