Patients with diabetic retinopathy have ERGs that become more abnormal with the progression of their retinopathy. The most sensitive features of the ERG to diabetic retinopathy are the oscillatory potentials (OPs). OPs are small wavelets on the ascending face of the ERG. OP amplitude is a sensitive predictor of progression to high risk characteristics in eyes with diabetic retinopathy, and provides unique predictive information that supplements ophthalmoscopy and fluorescein angiography.