Optic disc topographic analysis in diabetic patients

The aim of our study was to evaluate the optic disc (OD) topographic parameters by using Heidelberg Retina Tomograph II (HRT II) in patients with type 2 diabetes mellitus (DM). The study group consisted of 78 patients with type 2 DM (patient group) and age-sex matched 50 healthy subjects (control group). All patients and controls underwent a detailed ophthalmological examination, automated perimetry, central corneal thickness (CCT) measurement and OD topography by using HRT II. Glycosylated haemoglobin (HbA1c) levels of the diabetic patients were also noted. Age, gender, intraocular pressure and CCT measurements were similar in patients with diabetes and control group. Mean retinal nerve fiber layer thickness (MRNFLT) and retinal nerve fiber layer cross-sectional area (RNFLcsA) parameters were found significantly lower in diabetic patients compared to those of the controls (p = 0.030, p = 0.038). In the patient group, MRNFLT value was found significantly lower in patients with DM duration ≥120 months (p = 0.020) and HbA1c level ≥7 % (p = 0.029). Rim volume, MRNFLT and RNFLcsA values were significantly lower in proliferative diabetic retinopathy group (p = 0.004, p = 0.003, p = 0.001 respectively) and laser treated patients (p = 0.003, p = 0.002, p = 0.004 respectively). In conclusion, poor metabolic control of diabetes, severe DR and received laser therapies cause RNFL damage. Heidelberg Retina Tomograph may help us to detect and follow-up the changes in optic disc and RNFL in diabetic patients.