The Role of Electroretinography in Assessing the Progression of Diabetic Retinopathy

PURPOSE: To investigate the clinical significance of electroretinographic (ERG) responses, including the photopic negative response parameter, in assessing the progression of diabetic retinopathy. METHODS: Standard flash ERG was tested on 28 normal controls and 143 patients who were diagnosed with diabetes mellitus. Of those, 97 patients had diabetic retinopathy in different stages. Electroretinography was performed according to the International Society for Clinical Electrophysiology of Vision (ISCEV) standards. Amplitudes and implicit times of ERG responses, including the photopic negative response (PhNR), were compared at different stages of diabetic retinopathy. RESULTS: Amplitudes of oscillatory potentials were significantly reduced in mild NPDR. Cone b-wave amplitude, 30--Hz flicker response, and PhNR were significantly reduced in moderate NPDR. CONCLUSIONS: These results suggest that oscillatory potentials are good indicators of retinal function change in the early stage of diabetic retinopathy, and the appropriate results of the cone b-wave, 30-Hz flicker response and PhNR tests are good indicators of moderate NPDR.

Normal Values of Standard Electroretinography, and Change with Age and Sex (I)

Electroretinography has been used clinically for more than 50 years as useful retinal function test. But there has been no uniform recording signals, since various laboratories have employed different technologies and recording condition. Therefore, in 1989, International Society for clinical Electrophysiology of Vision (ISCEV) published Standard for clinical ERG, to ensure that ERG performed simply and uniformly worldwide for clinical and research purpose. We performed this standard ERG to 100 normal subjects whose range of ages were 8-79 years old. We obtained normal values of standard 5 basic response parameter. Additionally, we studied the parameter change according to age and sex. We found significantly decreased amplitude in the b-wave with age (p<0.05), and also obtained decreased rate b-wave amplitude with age. But no relation between b-wave implicit time and change of age was noted. B-wave amplitude found to be higher in women than in men (p<0.05).