A cataract is a lens that has become clouded. Many times, a patient will describe that looking through a cataract is like looking through a dirty window. The most modern technique available for removing cataracts is phacoemulsification. This is a small ultrasound device which removes the cataract by breaking it into microscopic pieces. With the clouded lens removed, a new, clear intraocular lens is inserted into the space previously occupied by the natural lens.