Effects of intensity of stimulation on signs of acute ischemia in the electroretinogram.

Acute retinal ischemia was induced in adult albino rabbits by clamping the retrobulbar blood vessels or raising the intraocular pressure. As the level of ischemia was increased, the b-wave amplitude and implicit time of response increased. However, the hyperresponsivity and delay of response were inversely related to the intensity of stimulation used, although at levels of ischemia above 70% there was a significant delay of response even with high-intensity stimulation. Thus, if early signs of acute ischemia are to be successfully monitored, low intensities of stimulation must be used.