Cross sectional case control study to establish the thickness of ganglion cell-inner plexiform (GC-IPL) layer thickness in type 2 diabetis (Type 2 DM) patients with diabetic retinopathy (DR) and compa

Aim: Primary Objective: To evaluate the macular GC-IPL layer thickness in Type 2 DM patients with diabetic retinopathy(DR) and compare its thickness with normal eyes. Secondary Objective: To identify any possible relationship between the GC-IPL thickness and grade of DR, duration of detected DM, age and gender of the patient. Materials and Methods: Patients were recruited from the outpatient clinic of the Department of Ophthalmology at Amrita Institute of Medical Sciences, Kochi, Kerala, India Inclusion criteria 1. Type 2 Diabetes with Mild Non Proliferative Diabetic Retinopathy (Mild NPDR) and Early Proliferative Diabetic Retinopath (Early PDR) without traction or vitreous hemorrhage (ETDRS classification) 2. Early proliferative diabetic retinopathy(PDR) was defined as presence of either neovascularisation of disc /elsewhere or preretinal hemorrhages or both (ETDRS) 3. Controls: Age-gender matched subjects free of ocular disease, diabetes, hypertension or other systemic diseases were recruited as controls from those who accompanied patients visiting the out patient clinic Statistically significant reduction of thickness of GC-IPL layer thickness between patients mild DR when compared to age matched controls (p=0.006). Results 1. Statistically significant reduction of GC-IPL thickness was seen in early PDR compared to controls (p<0.001). 2. GC-IPL layer were thinner in patients with mild NPDR when compared to age matched controls. 3. Difference in thickness between GC-IPL thickness between mild NPDR and early PDR was not statistically significant. 4. There was no relationship between GC-IPL thickness and duration of detected DM, age and gender of the patient. Conclusion 1. There was a statistically significant reduction of thickness of GC-IPL layer thickness between mild NPDR and Early PDR when compared to age matched controls. There was no significant difference between GC- IPL thickness between mild NPDR and early PDR. 2. These results support the concept that diabetes has an early neurodegenerative effect on the retina which occurs even before the vascular component of DR occurs. This reduction of GC-IPL thickness changes do not cause vision loss, but only supports neurodegenerative theory.