Non-anemic patients with neovascular age-related macular degeneration (AMD) who take oral iron supplements may be at risk of retinal/subretinal hemorrhage. Researchers have found that use of oral iron supplements was significantly associated with retinal/subretinal hemorrhage at baseline in patients with neovascular AMD. Particularly among those with hypertension, the association was dose-dependent.

A recent study investigated the association among participants in the Comparison of AMD Treatments trial, a multicenter study of anti-VEGF treatments for neovascular AMD. Among 1,165 participants, baseline retinal/subretinal hemorrhage was present in the study eye in 71% of 181 iron users and in 61% of 984 participants without iron use. The significant association was strongest among those taking an iron dose of 18mg to 36mg. The association also remained significant among hypertensive participants without anemia.

In AMD patients, the environment (iron supplements) may interact with genetics to damage vascular endothelial cells within the retina. Researchers believe further investigations should help elucidate the mechanisms of iron and complement dysregulation in retinal pigment epithelium and retinal vascular endothelial cells.