PIGGYBACK INTRAOCULAR-LENS WITH EXCHANGEABLE OPTIC

The exchange of a posterior chamber intraocular lens (IOL) is difficul t ii the lens is transsclerally or iris fixated or if a large posterio r capsulotomy exists. A piggyback IOL system was developed that allows adjustment of refraction in situ without removing the primarily impla nted IOL. The system comprises a posterior chamber IOL and a separate, exchangeable optic. Three succeeding designs were implanted in human donor eyes. The piggyback system's optical performance exceeded the re quirements for conventional posterior chamber IOLs. Thus, the lens cou ld be used in eyes in which postoperative refraction is likely to chan ge or is incorrect (e.g., in children or cases of combined cataract ex traction and corneal implantation).