Correlation of Retinal Nerve Fibre Layer Thickness with HbA1c and Oxidised LDL in Non-proliferative Diabetic Retinopathy

Abstract

Objectives: The purpose of this study is to determine the correlation of retinal nerve fibre layer (RNFL) thickness with glycosylated haemoglobin (HbA1c) and oxidised low density lipoprotein (LDL) among Type 2 non-proliferative diabetic retinopathy (NPDR). Methodology: This is a cross-sectional study involving 125 patients with Type 2 NPDR (mild NPDR: 45 patients, moderate NPDR: 45 patients and severe NPDR: 35 patients). Patients were evaluated for peri-papillary RNFL thickness by Heidelberg Retina Tomography. Blood were taken for HbA1c and oxidised LDL. Results: Severe NPDR showed the highest mean RNFL thickness (severe: 762.60 SD 209.57 μm, moderate: 738.24 SD 200.30 μm, mild: 700.27 SD 215.44 μm), however it was not significant (p=0.40). There was significant fair negative correlation between RNFL thickness and oxidised LDL in NPDR (r=- 0.391, p<0.001). However, there was no significant correlation between RNFL thickness and HbA1c (r=0.048, p=0.60). Conclusion: Early NPDR appears to have thinner RNFL thickness and is significantly correlated with high level of oxidised LDL.