_:vb50949338 . _:vb50949338 . _:vb50949338 . _:vb50949338 "url:https://en.wikipedia.org/wiki/Cataract"^^ . _:vb50949338 . _:vb50949338 "A senile cataract that is characterized by opacification of the lens nucleus and caused by changes related to aging."^^ . _:vb50949338 .