Cataract is an opacity of the lens. There are congenital forms, and those resulting from injuries and illnesses. The most common form, however is the age-related cataract, which usually develops after the age of 60. An effective drug therapy is not yet known. Currently, a cataract can only be eliminated surgically.
The current state of the art in the operation is to make an incision of approximately 2 to 4 mm through the conjunctiva and the sclera, or directly through the cornea into the anterior chamber. The anterior capsule of the natural lens of the patient is then opened and partially removed. Using ultrasound technology the nucleus is then liquefied and removed by suction (phacoemulsification).
Then the cortical masses of the lens are flushed and aspirated from the capsular bag. In most cases the capsular bag of the natural lens is retained. Using the same access into the anterior chamber of the eye which served the cataract removal, a folded artificial lens is inserted into the capsular bag. If the capsular bag can not be used, then it can alternatively be implanted in the ciliary-sulcus or into the anterior chamber.
As an alternative to ultrasound technology, techniques using laser or a fine water jet have been developed in recent years for cataract surgery. Due to unresolved technical problems, these techniques have not become a substitute for ultrasound and are only a real alternative for a small number of patients.
The most common materials for artificial lenses are soft acrylic, hard acrylic and silicone compounds.