The classical electroretinogram (ERG) has been intensively studied, mainly concerning its initial deflections (a- andb- waves), in various diseases of the eye since the systematic work initiated by Karpe1who defined several basic pathologic types of ERG. Several papers have appeared in relation to the classical ERG in diabetic retinopathy. François and Derouck3recorded the ERG in advanced diabetic retinopathy exhibiting numerous hemorrhages and exudates and saw the values in normal limits. Müller-Limmroth4and Schmöger5stated that in the early stage of diabetic retinopathy the ERG was found to be normal. Jacobson6believes that diabetic retinopathy usually does not compromise the ERG amplitude until the disease has reached far advanced stages, such as retinitis proliferans and detachment of the retina. Straub7examined the ERG's of 24 diabetic patients with slight retinopathy, demonstrating that the ERG was normal in 20 cases and subnormal in