[1] Johns Hopkins Univ, Sch Med, Wilmer Ophthalmol Inst, Dana Ctr Prevent Ophthalmol, Baltimore, MD 21287 USA
[2] Johns Hopkins Univ, Sch Publ Hlth, Wilmer Ophthalmol Inst, Dana Ctr Prevent Ophthalmol, Baltimore, MD 21287 USA
[3] Johns Hopkins Sch Hyg & Publ Hlth, Dept Int Hlth, Baltimore, MD USA
[4] Johns Hopkins Sch Med, Wilmer Ophthalmol Inst, Retinal Vasc Ctr, Baltimore, MD USA