Visual evoked potentials in diabetic patients

Currently there are conflicting results regarding optic neuropathy in diabetes mellitus. Therefore, the aim of the present study was to evaluate optic neuropathy in diabetic patients. We studied visual evoked potentials (VEPs) in 20 diabetic patients (6 insulin dependent, 14 noninsulin dependent; 8 women, 12 men; mean age: 49.70± 18.22 years; mean duration of diabetes: 9.33 ± 5.75 years) and 20 age-, and sex-matched healthy subjects (7 women, 13 men; mean age: 52.40 ± 16.02 years) as a control group. Nine of 20 diabetic patients had sensorimotor neuropathy, and 5 diabetic patients had both sensorimotor neuropathy and autonomic neuropathy, as well as 3 diabetic patients had diabetic retinopathy. P100 wave latency was significantly longer in diabetic pa-tients than those of the control group (p<0.0001). Forty-five percent of diabetic patients (9 patients) had P100 wave latencies above the normal range. There was no correlation between P100 wave latency and age, sex, degree of metabolic control or presence of degenerative complications. However, there was a significant positive correlation between P100 wave latency and the duration of diabetes mellitus (r=0.79, p<0.05). Our results abnormalities are dependent upon the duration of diabetes.