Abstract

Background: A more general involvement of the nervous system in diabetes, affecting not only the peripheral but also the central nervous system has been increasingly suggested over the last two decades. Electrophysiological investigations in the form of visual evoked potentials (VEPs) can be very sensitive and valuable method in evaluating central neural conduction in diabetics before the overt manifestations of ophthalmologic involvement.

Aims and Objectives: This study was planned to detect visual dysfunctions in type 2 diabetics at earlier stages by recording pattern reversal VEPs (PRVEPs).

Materials and Methods: PRVEP was recorded in 100 subjects (50 patients with type 2 diabetes and 50 controls). Mean latencies of N75, P100 and N145 waves, interocular latency differences (for P100 waves) and N75-P100 amplitude were compared between diabetics and the controls by unpaired t-test. P < 0.05 was considered as significant.

Results: A statistically significant increase in mean P100 latency (P < 0.0001) and interocular latency difference (P < 0.001) along with the reduction in N75-P100 amplitude (P < 0.0001) was revealed in diabetics as compared to the controls. Mean N75 and N145 latencies exhibited increase in diabetics but without statistical significance.

Conclusion: Electrophysiological alterations in the form of abnormal VEPs are registered in type 2 diabetes before clinically detectable ophthalmologic impairment. VEPs should be employed for assessing the visual functions in diabetics to ameliorate the prognosis of the condition.

Key words: Diabetes Mellitus; Central Nervous System; Visual Evoked Potentials