Retinal Nerve Fiber Layer Thickness in Prediabetic Patients

Objective: Diabetic retinopathy is a leading cause of blindness. Diabetic retinopathy is not only seen in diabetic patients with the clinical diagnosis but also in prediabetic patients. The aim of this study is to evaluate the RNFL thickness in prediabetic patients. Materials and Methods: In this study, 50 prediabetic patients and 50 healthy individuals were included. RNFL measurements were performed with SD-OCT in patients with prediabetes and healthy controls. Results: The mean RNFL thickness for the prediabetic group was 94.7 ± 6.3 μm, inferior quadrant (120 ± 11.6), superior quadrant (112.3 ± 14.13), nasal quadrant (71 ± 12.9), and temporal quadrant (65.3 ± 9.2 μm). The mean RNFL thickness for the control group was 98.9 ± 7.5 μm, inferior quadrant (128 ± 14.7), superior quadrant (116.3 ± 15.12), nasal quadrant (77 ± 15.8), and temporal quadrant (71.2 ± 10.3 μm). Variance analysis demonstrated that the RNFL thickness difference between the groups was significant in all quadrants (P < .001). Conclusion: RNLF thinning can be seen in prediabetic patients before obvious vascular damage has occurred, and it may present in prediabetic patients not only in the temporal quadrant but also in all quadrants. The early retinal neural changes shown in this study in prediabetic patients may help to better understand the process leading to diabetic overt retinopathy.