Abstract
Purpose :
It is known that the implicit time of flicker ERGs is useful way to evaluate the degree of ischemia in eyes with central retinal vein occlusion (CRVO). During our study of flicker ERGs in eyes with CRVO, we noted that the amplitudes of the flicker ERGs in eyes with CRVO had “super-normal” flicker ERG amplitudes. The purpose of this study was to determine the clinical characteristics of CRVO patients associated with “super-normal” flicker ERG amplitudes.
Methods :
Twenty-two eyes from 22 patients with CRVO (13 men, 9 women; mean age, 71.0 years), who visited our hospital within two years of the onset of the CRVO and underwent flicker ERG recordings from both eyes, were studied. After full mydriasis, the flicker ERGs were recorded with RETeval, a small, hand-held ERG recording system using skin electrodes. The amplitudes and implicit times of the fundamental component were analyzed. “Super-normal” flicker ERGs were defined as those whose amplitudes were larger than 110% of that in the unaffected eye.
Results :
Of all 22 eyes, there were 15 non-ischemic CRVO and 7 ischemic CRVO. Seven eyes (32%) had “super-normal” flicker ERG amplitude, and all of these eyes were those with non-ischemic CRVO. The ratio of the amplitudes of the affected eye to the unaffected eye was 136±19% in the “super-normal” group, and 88±33% in the other eyes. The difference of the implicit times between the affected eye and unaffected eye was 2.2±1.2 ms in the “super-normal” group and was significantly shorter than in the other eyes (5.1±2.6 ms).
Conclusions :
We found that about 30% of the eyes with CRVO had “super-normal” flicker ERG amplitude. “Super-normal” flicker ERGs were mainly observed in eyes with mild non-ischemic CRVO. This phenomenon may be a sign of good prognosis for eyes with a CRVO.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.