Artificial eye lens. Intraocular lens (IOL) implant used to replace the lens of an eye affected by a cataract. Cataracts are a clouding of the lens of the eye caused by the gradual denaturation of the proteins that make up the eyes lens. Cataract extraction procedures can be used to remove the cloudy lens from the eye. An IOL implant such as the one shown here is then placed into the remaining lens capsule.