It is because of the cloudy lens that cataract occurs. Once you clean out or replace that defected lens with a good manmade one, it is removed. That is, in cataract procedure, the defected one is replaced by an intraocular lens (IOL). It is beneficial. It does not just corrects the vision, instead provides a full range of vision.
My uncle had cataract and he got it removed through cataract treatment and he doesn't have any vision problem now. He got it done from Toronto Eye Surgery Centre. They are very passionate about our eyesight.