Background: Retinal vasculitis is a potentially sight-threatening inflammation of the retinal vessels, but little is known about the in vivo vascular changes, which occur in affected eyes. The authors therefore sought to measure vessel caliber in eyes with vasculitis.
Methods: Retrospective case-control study. Vasculitis was confirmed using fluorescein angiography. Vessel calibers were measured using validated semiautomated software.
Results: There were 21 eyes from 15 patients with vasculitis and 33 control eyes from 21 control subjects. Most cases were diagnosed with idiopathic vasculitis. All had periphlebitis, and one eye also had arteritis. After adjustment for age and gender, mean arteriolar caliber was 143 μm (95% confidence interval [CI], 134-152) in cases and 158 μm (95% CI, 151-165) in controls (P = 0.01). Venular caliber was similar in cases (229 μm; 95% CI, 215-243) and controls (228 μm; 95% CI, 217-234; P = 0.91), whereas arteriole-to-venule ratio was smaller in cases (0.63; 95% CI, 0.60-0.66) compared with controls (0.70; 95% CI, 0.02-0.11; P = 0.004).
Conclusion: Retinal vasculitis was associated with narrower arteriolar caliber, whereas venular caliber was similar to controls. This resulted in a smaller arteriole-to-venule ratio in eyes with vasculitis.