Prevalence of ocular hemorrhage in patients receiving warfarin therapy

Background: Warfarin, the drug most commonly used for outpatient anticoagulation therapy, has bleeding as its main side effect. The objective of this study was to determine the prevalence of ocular hemorrhage in patients receiving warfarin and to compare it to the prevalence in the general population. Methods: Patients receiving warfarin therapy who were attending the anticoagulation clinic at a tertiary care hospital in Montreal between October and December 1996 received a flyer inviting them to have their eyes examined to look for "ocular bleeding." Consenting patients were examined for subconjunctival hemorrhage, gross hyphema, and vitreous and retinal hemorrhages through external ocular examination and funduscopic examination with the pupils dilated using direct and indirect ophthalmoscopy. Results: Of the 1225 patients seen at the clinic 126 (10%) agreed to participate. Four patients (3%) were found to have intraretinal hemorrhage at the time of examination, All hemorrhages were visually insignificant. Interpretation: The risk of retinal hemorrhage in patients without preexisting ocular disease, such as retinal neovascularization or choroidal vasculopathy, who are receiving warfarin therapy is so small that it should not deter physicians from prescribing this drug when indicated.