Abstract
Abstract: :
Purpose: To examine the changes of electroretinogram (ERG) waveforms using repeated–flash photo–stimulation in patients with Oguchi disease. Methods: Flash ERGs were recorded on 6 eyes (3 patients, age 33±30 y.o.) with Oguchi disease. Twenty–five normal eyes (age 42±22 y.o.) were served as a control group. Two ERG series were recorded using white light–emitting–diode built–in contact–lens electrode. The first ERG series was recorded after 40–minute period of dark adaptation (DA series), and the second ERG series was recorded after 10–minute period of light adaptation (LA series). In both series, photo–stimulation was made four times with an interval of 20 seconds between flashes. Amplitude and peak time of a– and b–waves were measured and evaluated. Results: In normal subjects, amplitude of a– and b–waves in LA series was significantly smaller than that in DA series (p<0.01). However, no significant change was made in a–wave amplitude by repeated photo–stimulation in both series. In Oguchi disease, a–wave amplitude of the first ERG in DA series was significantly larger than that of all other ERGs including LA series (Figure, average 166%, p<0.01). No significant difference was shown in a–wave amplitude among all ERGs in both series, except the first ERG in DA series. Conclusions: These findings suggested the dark–adapted retina in patients with Oguchi disease could be bleached completely with single–flash photo–stimulation. These facts supported the Mizuo phenomenon in Oguchi disease, electrophysiologically.
Keywords: electroretinography: clinical • retinal degenerations: hereditary