Abstract
Abstract: :
Purpose: A normal light-EOG requires both normal rods and a normal retinal-RPE interface. It follows that normality in the light-EOG is not in itself diagnostic of RPE function. Alcohol affects the EOG in ways very similar to light, though the two agents act on the RPE via different routes. We have investigated whether light and alcohol have differential effects in ARM, which would be of clinical significance. Methods: Standard EOG recording techniques. 17 patients with ARM, aged 67-86 years. The patients' condition varied from a few visible drusen to large areas of "wet" or "dry" degeneration. After 26 minutes baseline recording in darkness, subjects were either exposed to 30 cd/m2 light or drank 226 mg/Kg alcohol, 7.1% v/v in water. Results: The EOG results are insignificantly correlated with age. The peak of the alcohol-EOG is reduced more than that of the light-EOG (p<0.001) . The reduction in the alcohol response is the same for both eyes, regardless of differential visual impairment in each eye. Both EOGs are slightly delayed relative to normal. Compared to the least affected 4 patients, the alcohol EOGs of the 4 most affected are smaller and more delayed. Conclusions: In ARM (1) alcohol-EOGs are more affected than light-EOGs. (2) Even with minor fundal changes, patients appear to have a general abnormality of the RPE, providing an early indicator of future visual losses. (3) These results are consistent with histological and other evidences that there is a functional barrier between choroid and RPE and suggest a large proportion of the RPE responds abnormally.
Keywords: age-related macular degeneration • electrophysiology: clinical • retina