Electroretinogram recovery in the rabbit after repetitive short-term ischemia in light and dark.

PURPOSE To determine the time course and reproducibility of electroretinogram recovery after short-term (5- to 20-minute) retinal ischemia in the light and in the dark. METHODS Electroretinogram recovery was measured in Dutch rabbits after 5-, 10-, or 20-minute episodes of ocular ischemia, repeated three times at 1-hour intervals. Results were compared under light- and dark-adapted conditions. RESULTS The rate of b-wave recovery was highly reproducible after repetitive ischemic insults in the same eye. The rate of b-wave recovery varied in proportion to the duration of ischemia but generally reached 100% of preischemic levels within 45 to 60 minutes. Recovery was slower under dark-adapted conditions than under light-adapted conditions, and 10 minutes of ischemia appeared to be a critical duration to maximize light- and dark-adapted metabolic differences. CONCLUSIONS Because of the speed and reproducibility of electroretinogram recovery, the use of short-term ischemic episodes may facilitate studies on the pharmacologic therapy of retinal ischemia. It remains to be determined, however, whether the retinal effects of short-term ischemia are mediated by the same mechanisms as the effects of longer-term ischemia.