Object: The measurement of Ganglion Cell Complex in diabetic patients could be an early indicator of neuronal loss pointing to the central vision loss. In this study, we estimated the thickness of ganglion cell complex in Type-2 diabetic patients with or without retinopathy and observed the impact of diabetes on retinal ganglion cells. Methodology: After approval from our institutional ethical committee (VMMC/OPH/2019/01), this prospective study was conducted in the Department of Ophthalmology, Vinayaka Mission’s Medical College, Karaikal. Totally 150 adult onset type 2 diabetic patients were recruited in the study. The study population was divided into 3 groups. Group 1- Normal healthy individuals, Group 2- Patients with Type-2 diabetes mellitus patients without diabetic retinopathy, Group 3- Patients with Type-2 diabetes mellitus patients with all grades (mild, moderate, severe) of Non proliferative retinopathy (According to ETDRS classification). Results: In this study the mean age of group I was found to be 53.78 + 9.18 years, group 2 was 52.64 + 10.14 and that of the Group 3 was 57.70 + 11.48 years. The average ganglion cell complex showed a statistically significant correlation in majority of sectors among the groups. The GCC complex thickness was affected more in superior than inferior sector. The nasal sector showed significant thinning of GGC than temporal. The duration of diabetes mellitus and the hyperglycemic level showed an inverse correlation to GCC thickness. Conclusion: This study noticed a significant GCC thinning in diabetic patients. Hence OCT can be a useful non-invasive tool for early detection of neuronal loss even before retinopathy changes are seen.