Abstract: Objective To assess the changes and associations of retinal vascular caliber in early stages of diabetic retinopathy (DR) in type 2 diabetic patients. Design Case-control study. Participants 85 patients with type 2 diabetes (51~80 years old) and 26 age-sex-matched subjects without diabetes (51~78 years old) from Beijing Desheng Community Diabetic Eye Disease Study were used as controls. Methods 85 patients with type 2 diabetes were divided into two groups according to DR: no DR (NDR) group (51 cases), and mild to moderate nonproliferative diabetic retinopathy (NPDR) group (34 cases), compared with 26 non-diabetic control subjects. Central retinal arterial equivalence (CRAE) and central retinal vein equivalence (CRVE) were measured using computer software. Central macular retinal thickness was measured using spectral domain optical coherence tomography (OCT). Best corrected visual acuity (BCVA), diabetes duration, height, weight, glycosylated hemoglobin and other data were recorded. The differences of CRAE and CRVE among the three groups were compared, and possible related factors were analyzed. Main Outcome Measures CRAE, CRVE. Results The CRAE of the right eye of the non-diabetic control group, the right eye of the NDR group and the severely diseased eye of the NPDR group were (151.91±13.65) μm, (156.73±11.53) μm, (154.08±9.82) μm (F=1.58, P=0.21); CRVE was (226.60±11.84) μm, (231.70±15.65) μm, (244.59±13.82) μm (F=13.43, P<0.01); CRVE in NPDR group was significantly wider than that in non-diabetic control group and NDR group (P<0.01 for both), while there was no statistical difference of CRVE between the control and NDR groups (P=0.42). Multivariate linear regression analysis showed that CRVE was negatively correlated with age in the three groups (P<0.01, all). Conclusion CRVE in the three groups of patients in this study was negatively correlated with age; CRVE in NPDR group was significantly wider compared with the control and NDR group. (Ophthalmol CHN, 2022, 31: 195-199)

Key words: retinal vascular caliber, type 2 diabetes mellitus, diabetic retinopathy