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Effect of Niacin on Retinal Vascular Diameter in Patients with Age-Related Macular Degeneration

Purpose: Niacin is a B vitamin well-known for causing vasodilation and flushing. The purpose of this study was to investigate its effect on the retinal vasculature of patients with age-related macular degeneration (AMD). Methods: Twelve patients with AMD were enrolled in a double-blind, randomized, placebo-controlled, crossover trial. Fundus photographs of the posterior pole were taken at baseline, 30 min, and 90 min after a single dose of niacin or placebo. The protocol was repeated after a washout period using the alternate study drug. The diameters of two veins and one artery on each image were measured. Results: An analysis of variance for repeated measures comparing the effects of niacin with those of placebo demonstrated a significant increase in the inferior temporal retinal artery diameter (p = 0.01), with a 5.3 ± 7.7% increase at 30 min (p = 0.05) and 5.8 ± 5.0% increase at 90 min (p = 0.003). No significant changes were observed in the temporal retinal veins. Conclusions: Our results suggest that niacin produces vasodilatation of retinal arterioles. Further studies are needed to ascertain whether niacin treatment may be beneficial in retinal ischemic diseases.