Use of Clopidogrel and Poor Visual Outcome

I read with interest a recent article by Chae et al.,¹ which was published in Investigative Ophthalmology & Visual Science. In their study, the use of clopidogrel was associated with poor visual outcome at 2 years. The authors postulated that this association may be related to the association between neovascular age-related macular degeneration (AMD) and cardiovascular disease. 

I agree with the authors' opinion. However, I believe that verifying whether the development of submacular hemorrhage during the follow-up period contributed to the poor visual outcome in patients using clopidogrel may provide useful information to clinicians. It is well known that submacular hemorrhage is associated with poor visual outcome in neovascular AMD. Recently, antivascular endothelial growth factor (VEGF) monotherapy was found to be an effective treatment for this condition.^2,3 However, visual acuity was restored to the same level as that before the development of hemorrhage in only a limited proportion of patients,² suggesting the negative influence of hemorrhage on visual prognosis. Previous studies have shown that the use of anticoagulants, including clopidogrel, is associated with an increased risk of hemorrhage in patients with neovascular AMD.^4,5 For this reason, I suspect that the development of submacular hemorrhage during the treatment course may partially influence the poor visual outcome in patients using clopidogrel. A brief description of the incidence of fovea-involving submacular hemorrhage and a comparison of the incidence between patients with and without use of clopidogrel may be helpful to address this question.