Retinal Vascular Caliber Changes in Early Type 2 Diabetic Patients without Retinopathy

Purpose: To evaluate the retinal vascular caliber in early type 2 diabetic patients without retinopathy. Methods: This retrospective study reviewed the medical records of 85 patients who were diagnosed with type 2 diabetes (age, 10-48 years) and sex-matched healthy controls. Dilated fundus examinations were performed to confirm the absence of diabetic retinopathy. Fundus photographs were acquired and analyzed using software that semi-automatically measured retinal vascular caliber. Central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE), and arteriovenous ratio (AVR) were determined using the revised Parr-Hubbard formula. Healthy controls were examined using the same approach. Results: There were no significant differences between patients and controls in terms of CRAE (149.92 +/- 21.29 mu m and 144.85 +/- 17.14 mu m, respectively; p = 0.137) or CRVE (195.85 +/- 22.94 mu m and 196.69 +/- 18.43 mu m, respectively; p = 0.829). However, AVR was significantly higher in the patient group (0.768 +/- 0.088 vs. 0.737 +/- 0.061; p = 0.031). In the patient group, AVR was significantly correlated with hemoglobin A1c (r = 0.325, p = 0.006), but not with body mass index (p = 0.478). Conclusions: An increase in peripapillary AVR may be an early feature of retinal vessels observed in patients with type 2 diabetes, which is closely related to elevated blood sugar.