2Asist. Dr., Srimati Kanuri Shanthamma centre for vitreoretinal Diseases, L. V. Prasad Eye Institute, Hyderabad, India
3Asist. Dr., Department of Optometry, University of Hyderabad, Hyderabad, India DOI : 10.37845/ret.vit.2022.31.51 Purpose: To determine how photopic negative response (PhNR) of elctroretinogram (ERG) is affected in diabetes subjects with and without retinopathy and to compare it with the controls in Indian subjects.
Methods: Fifty-nine subjects were divided into control, diabetes with no retinopathy, non-proliferative diabetic retinopathy (NPDR), and proliferative diabetic retinopathy (PDR) groups. All subjects photopic ERG parameters were measured using short duration (4 milli seconds) red flashes (1.7 cd..m-2) on blue background (8cd. m-2). Photopic ERG parameters, a-wave amplitude, a-wave implicit time, b-wave amplitude, b-wave implicit time and PhNR amplitudes were measured in all the subjects.
Results: 25 eyes of 14 subjects with diabetes, 37 eyes of 30 subjects with various stages of diabetic retinopathy and 24 eyes of 15 age matched control subjects were studied. There is a significant reduction (p < 0.05) in PhNR amplitude along with other ERG parameters such as a-wave amplitude, a-wave implicit time, b-wave amplitude, b-wave implicit time in diabetic retinopathy subjects when compared to control and diabetes subjects but there is no significant difference (p > 0.05) in photopic ERG parameters between controls and diabetic subjects and also between NPDR and PDR subjects.
Conclusion: PhNR amplitude along with the other photpic ERG parameters is useful for the evaluation of inner retinal function in cases of diabetic retinopathy when compared to early stages of diabetes.
Keywords : Photopic Negative response, electroretinogram, diabetes, non proliferative, proliferative, retinopathy