Correlation between Retinal Nerve Fibre Layer Thickness and Glycosylated Haemoglobin in Non Proliferative Diabetic Retinopathy

Abstract

Abstract Background Diabetes mellitus is a metabolic disorder characterized by chronic hyperglyaemia. Diabetes cause many complication. diabetic retinopathy is common complication which affects up to 80 percent of all patients who have diabetes for more than10 years or more. Retinal functional abnormalities as reduced contrast sensitivity and ERG abnormalities could be detected in diabetic patients before microvascular lesions can be detected in ophalmological examination. Purpose to determine correlation between retinal nerve fibre layer thickness measured by Optical coherence tomography and glycosylated haemoglobin in type 2 non proliferative diabetic retinopathy. Patients and Methods In our study was conducted on patient recruited from National institute of Diabetes and endocrinology in the ophthalmic clinic. Patients were evaluated for peri-papillary retinal nerve fibre layer ( RNFL) thickness by optical coherence tomography (RS 3000 advance). Blood were taken for HbA1c. The study was included 164 eyes from 87 patients. The patients were non proliferative diabetic retinopathy(NPDR) classified into three groups according to Early Treatment Diabetic Retinopathy Study into; Mild group was 69 eyes from 35 patients, moderate group58 eyes from 31 patient, Severe group 37 eyes from 21 patients. Results The severe group show statistically significant difference with the others (P < 0.001) except with mild group in nasal and inferior quadrant, therefore the thickness was high in the severe groups because the edema in RNFL. In our study we observed decrease in total thickness of RNFL in peripapillary area. However, among each quadrant we observed that the superior quadrant was thinner compared to other quadrants (p < 0.001). There was insignificant correlation between RNFL thickness with the Glycosylated haemoglobin ( HbA1c )in all NPDR groups. Conclusion Early NPDR patients appear to have thinner RNFL thickness and severe NPDR patients show increasing RNFL thickness. There are not correlation between RNFL thickness and glycosylated haemoglobin.