Electrophysiological study of optic pathways in insulin dependent diabetes mellitus

1. Pattern reversal visual evoked potentials (VEPs) and pattern electroretinograms (PERGs) at different spatial frequencies were recorded from 35 insulin dependent diabetes mellitus (IDDM) patients with normal visual acuity. 2. In addition, VEPs with 7.5' checks were examined at three contrast levels (10, 25 and 50% contrast). 3. The frequency of abnormal VEPs increased with increasing spatial frequency of stimulation and with decreasing contrast levels. 4. The mean PERG amplitude was significantly reduced at all spatial frequencies and contrasts in IDDM patients. 5. The mean VEP latency from eyes with reduced PERG amplitude was significantly increased over the mean VEP latency from eyes with normal PERGs. 6. PERG amplitude reduction seems to be the earliest detectable electrophysiological abnormality of the optic pathways in IDDM patients.