Comparing the Doppler flow parameters of orbital vessels among healthy nonsmokers, diabetic nonsmokers, and diabetic smokers visiting a tertiary health-care center.

Purpose: The present study aimed to assess the impact of diabetes mellitus and smoking in orbital vessels, utilizing resistive index (RI) through color Doppler imaging (CDI).

Materials and methods: The cross-sectional study consisted of 90 participants divided into three groups of 30 each. Group A consisted of normal individuals, Group B consisted of patients with diabetes, and Group C consisted of patients with a history of diabetes and smoking. The RIs were obtained for the orbital vessels for both eyes using CDI. Analysis of variance with post hoc Tukey's HSD test was conducted for pairwise comparison of the groups. Pearson's correlation test was used to correlate between RI and the amount of smoking.

Results: Significant differences were observed in the mean RI values of the ophthalmic artery, central retinal artery (CRA), and central retinal vein (CRV) in all three groups bilaterally (P < 0.001). Compared with patients in Group A, those in Group B had significantly larger RIs for all orbital vessels in both eyes (P < 0.01 for all). Patients in Group C had significantly larger RI for all three vessels (P < 0.001 for all) except for the CRV in the right eye than those in Group A. Compared with patients in Group B, those in Group C had significantly larger RI in CRA bilaterally (P = 0.05 for the right eyes and P = 0.024 for the left eyes). In Group C, a positive correlation was observed between RIs of all orbital vessels and the amount of smoking.

Conclusion: RIs of the orbital vessels are significantly increased in patients with diabetes and higher in diabetic smokers, suggesting that diabetes affects the retinal vasculature, and smoking exacerbates this pathology.