Author(s): Bhanu R., Vinutha Shankar M.S., Karthiyanee Kutty, Nachal Annamalai
Diabetes Mellitus (DM) has detrimental effects on the various organs of our body including peripheral nervous system, which are widely accepted. However, not much research is done on understanding the central nervous system (CNS) abnormalities in DM. Visual evoked potential (VEP) is a non-invasive neurophysiological examination that detects early diabetic retinopathy changes, which is important in preventing loss of vision. Aim was to evaluate the efficacy of VEP in detecting retinal ganglion cell damage in diabetics and to correlate between P100 latency in milliseconds (ms) and duration of diabetes. This study included 20 diagnosed DM type II patients of more than 2 years duration and without any clinical complications. 20 age and sex matched subjects were taken as controls. VEP was recorded using pattern reversal stimulation with EMG RMS MARK II machine. P100 latencies (ms) was significantly prolonged in diabetics with mean ± SD of (110.14 ± 5.30 ms) as compared to controls (100.17 ± 0.75 ms) with p value <0.001. Significant positive correlation was found between duration of diabetes and P100 latencies (r =0.63; p=0.003). It can be concluded that the prolongation of P100 latencies observed in diabetics could be a manifestation of structural damage at the level of the myelinated optic nerve fibres or retinal ganglion cell damage before development of diabetic retinopathy and P100 latencies showed significant positive correlation with duration of diabetes.