[Analysis of focal macular ERG in idiopathic central serous chorioretinopathy]

Focal macular electroretinogram (MERG), was analyzed in 33 patients with unilateral central serous chorioretinopathy (CSC) of recent onset. The stimulus spots were 5 degrees, 10 degrees and 15 degrees in diameter. Nonaffected fellow eyes served as controls. When macular detachment was present, the MERG showed significantly reduced amplitude and delayed peak latency in a-wave, b-wave and oscillatory potentials (OPs) in all stimulus spots. The reduction of amplitude in 5 degree and 10 degree spots was more significant in b-wave and OPs than in a-wave. In the convalescent stage, the a-wave and b-wave recovered to nearly normal levels, however OPs showed selective delay of recovery. These abnormalities shown by MERG strongly suggest that CSC may involve functional disturbances in the inner retinal layer as well as photoreceptors. It has been assumed that the pathogenic properties of CSC are receptor disorientation and a disturbance in the rate of photopigment regeneration. The present study showed that the abnormal pattern of MERG in CSC cannot be explained simply by the assumption of receptor disorientation or a disturbance of photopigment regeneration by analyzing similar conditions in normal eyes.