Diplopia after cataract surgery.

A 69-year-old man developed binocular, vertical diplopia after undergoing cataract extraction in both eyes. He had normal extraocular motility and a 2 prism diopter right hypertropia that was comitant but could not be relieved with overlying prisms. Funduscopy revealed an epiretinal membrane within the macula on the left more than the right. After his metamorphopsia worsened, and his visual acuity decreased to 20/40 in the left eye, he underwent pars plana vitrectomy with removal of the epiretinal membrane and his diplopia resolved. Macular pathology including epiretinal membranes and choroidal neovascular membranes may rarely cause binocular diplopia because of foveal displacement and rivalry between central and peripheral fusional mechanisms.