A cataract operation involves removing the natural cloudy lens from the eye. Without a lens within it the eye is widely out of focus and remains legally blind. The best remedy for this is to insert an artificial lens into the eye. This is now a standard part of cataract surgery, though it has not always been so.
This artificial lens is called "The Intra Ocular Lens Implant".
Surgeons often refer to it as the IOL (Intra Ocular Lens). If a lens implant is not used the eye must be brought into focus with either a spectacle lens or contact lens. Each of these has disadvantages. A spectacle lens will be thick, heavy and restrict the field of vision. A contact lens has to be looked after and taken on and off the eye. An intra ocular lens once inserted can be forgotten about by the patient and restores the eye to the most nearly natural state.