Biomaterials for ocular implants: an opthalmologist's perspective

The dramatic change in cataract surgery and intraocular lens (IOL) implantation occurred with the introduction of the posterior chamber IOL in the mid 1970's. A significant trend has been the widespread us eof the one piece PMMA IOLs because of the cleaner smoother surface of this design and the fact that there are no discontinuities in the optic surface as with the 3 piece lens. In the current climate there has been a major movement toward small incision cataract surgery. This type of surgical technique is exemplified by phacoemulsification although there are other methods to remove a cataract through less than the conventional incision size for extracapsular surgery. Opthalmologists have considered an ideal cataract procedure as one where the capsule bag would be maintained with the lens material removed through a small opening in the capsule. The residual germinative lens epithelial cells are removed chemically and/or with ultrasound or laser surgery and a biocompatible material with appropriate optical clarity, refractive index and biomechanical properties is injected to fill the capsular bag and restore the qualities of the crystalline lens. This is a potential challenge for the future in the quest to make an excellent procedure an almost perfect one.