Electrophysiological evaluation in patients with type 2 diabetes mellitus by pattern reversal visual evoked potentials

Diabetes Mellitus; Central Nervous System; Visual Evoked Potentials INTRODUCTION Type 2 diabetes mellitus has a dramatic increase in its prevalence and incidence globally owing to the behavioral and lifestyle changes in the people in the recent years. [...]long before the clinically evident structural alterations in the retina and in visual pathways are diagnosed, this objective and noninvasive electrophysiological technique can help detecting the functional alterations in the visual system.16 Hence, this study was planned to evaluate the patients with type 2 diabetes mellitus before the development of diabetic complications, by PRVEPs. Out of 100 subjects, 50 subjects were those who were diagnosed with type 2 diabetes mellitus among the patients attending the Department of Medicine at Maharishi Markandeshwar Institute of Medical Sciences and Research, Mullana, Ambala, Haryana, India. 50 subjects were age and sex-matched healthy controls from the area of study (students and staff of the institute). Sample size was estimated on the basis of Pearson's correlation coefficients for P100 latency and duration of diabetes, obtained from previous studies which ranged from 0.570 to 0.790. [7-9] To obtain maximum possible sample size, lower value of correlation coefficient of 0.570 was taken. [7] A sample size of 46 diabetics was calculated accordingly at 5% significance level and power of 99%. All the patients with type 2 diabetes mellitus (proven by recent blood glucose studies with fasting plasma glucose values exceeding 126 mg/dl, as per the WHO criteria) with normal visual acuity or corrected by glasses and normal fundus examination and without...