Electroretinographic Findings in Diabetics with No Observable Retinopathy

Lee, Sang Hee; Kim, Sang Ha

Abstract

Five common electroretinograms and Fourier transform of the oscillatory potentials were recorded in adult diabetic patients with no observable retinopathy. To describe the limits of normal, we listed the median value, and actual values on either side of median that bracket 95% of the normal responses. In 68 of the 80 normal control eyes(85%), all ERG components were within normal limits. Only 52 of the 146 eyes in no diabetic retinopathy(35%) showed perfectly normal ERGs to our standard. The difference between the normal control eyes and diabetic eyes was statistically significant(p< 0.05 by Chi-square test). This fact may give proof that functional disturbance precedes the visible abnormalities of retina. A amplitude reduction of the second oscillatory potential and a timing delay of the maximal response a-wave were of frequent occurrences in diabetic patients with no retinopathy. The amplitude of the second oscillatory potential may be the best indicator reflecting erly retinal ischemic state, because a amplitude reduction attracts the examiners` eyes better than a timing delay.