A31: Siderosis bulbi is caused by retention and oxidation of an iron-containing intraocular foreign body. Clinical features include cataract, rust-colored anterior subcapsular deposits, iris heterochromia (affected side is darker), pupillary mydriasis, and depressed electroretinogram (ERG) amplitudes. Other potential sequelae include pigmentary retinopathy, retinal microangiopathy, and open-angle glaucoma. If the cataract and foreign body are removed and there is no macular trauma, the visual prognosis is excellent.