Nerve fibre layer thinning in patients with preclinical retinopathy

Abstract

Objective: To compare retinal nerve fibre layer thickness (RNFLT) obtained by optical coherence tomography (OCT) between patients with preclinical diabetic retinopathy (DR) and healthy subjects. Study Design: Cross-sectional study. Participants: Ninety-nine type I or II diabetic patients with no visible funduscopic retinal alteration and 77 healthy subjects were included in this study. Methods: All participants were evaluated for peripapillary RNFLT by Stratus OCT. In diabetic patients, levels of blood sugar and glycosylated hemoglobin were examined. Results: The mean RNFLT in diabetic patients and healthy subjects was significantly different (104.2 [SD 10.4] and 108.6 [SD 9.2] mm, respectively; p = 0.004). Compared with the healthy group, the RNFLT in the diabetic group was also significantly less in the superior quadrant and at the 5,11, and 12 o'clock sectors (p = 0.04, 0.002, and 0.001, respectively). The average RNFLT in diabetic patients with preclinical DR showed a low correlation with fasting blood sugar level (p = 0.03). Conclusions: The mean and superior quadrant peripapillary RNFLT was slightly less in diabetic patients without abnormal vascular manifestations than in healthy subjects. Furthermore, lower RNFLT values in patients with pre- clinical DR appears to be weakly associated with high levels of fasting blood sugar.