Loss of visual function in diabetes mellitus

Abstract

Background: Diabetes mellitus being a well-known cause for peripheral neuropathy, this study aims to detect visual pathway dysfunction in diabetics using contrast sensitivity as a subjective measure and visual-evoked potential (VEP) as an objective measure of visual pathway function. Aims: To compare contrast sensitivity and VEP in patients with type 2 diabetes mellitus as compared with control and to find the correlation with glycemic level. Materials and Methodology: This was a comparative study conducted at a tertiary eye care center. After detailed ophthalmological evaluation, contrast sensitivity and VEP of 40 patients with diabetes (20 with retinopathy and 20 without retinopathy) were compared with suitable control. Data were analyzed using the SPSS (Statistical Product and Service Solutions) version 18 using the independent sample t-test and ANOVA. Results: There was reduction of mean contrast sensitivity in diabetics as compared to nondiabetics. Contrast sensitivity was better in diabetics without retinopathy as compared to diabetics with retinopathy. There was prolongation of P100 latencies and reduction of P100 amplitudes among diabetics as compared to non-diabetics and among those with diabetic retinopathy as compared to those with normal fundus. Reduced contrast sensitivity and reduction of P100 amplitudes were seen among those with poor glycemic control. Conclusion: There was evidence of reduction of contrast sensitivity and alteration of VEP in patients with diabetes even before reduction in visual acuity giving evidence of visual pathway dysfunction in diabetes mellitus. This may also be affected by the glycemic status of the patient.

Keywords

• contrast sensitivity
• glycemic control
• visual-evoked potential
• visual pathway dysfunction