Electroretinographic oscillatory potentials predict progression of diabetic retinopathy. Preliminary report

The oscillatory potential (OP) amplitudes of the electroretinogram (ERG) were determined in a group of 85 diabetic patients entering the Early Treatment Diabetic Retinopathy Study (ETDRS). The rate of progression among nonphotocoagulated eyes to the Diabetic Retinopathy Study high-risk characteristics (DRS-HRC) during a ten- to 40-month follow-up period was determined. Progression occurred in 19 of 85 eyes at risk. Those eyes with abnormal OP amplitudes (less than or equal to 75 microV) at study entry had a tenfold higher rate of progression to DRS-HRC than did eyes with normal amplitudes (greater than 75 microV). Although the level of retinopathic severity at study entry was a significant factor in the rate of subsequent progression, the amplitudes of the OPs remained a significant risk factor even after correcting the initial retinopathic level. The ERG seems to be a useful clinical tool in predicting the rate of progression of diabetic retinopathy. The reduction in OP amplitudes probably is a quantitative measure of the degree of overall inner layer retinal ischemia.