CORNEAL TRANSPLANTATION AND THE ARTIFICIAL CORNEA
The clinical need for an alternative to donor corneal tissue has encouraged much interest in recent years. An artificial cornea whether it be bio-engineered or a synthetic keratoprosthesis must fulfill the functions of the cornea it replaces: transparent, refractive surface, protection, non-immunogenic. A wide range of implants and biomedical devices have been developed in an attempt to correct corneal blindness. Limitation of existing biomaterials are evident when reviewing keratoprosthesis surgery complications. These include infection, intraocular inflammation, retromembrane formation, inadequate interface seal thus epithelial downgrowth and glaucoma. Attempts to improve healing in such cases have involved using various polymers or tissues to surround the optic. The successes and failures of synthetic prostheses that have been implanted in humans is discussed. More recently, the idea of a bio-engineered cornea has arisen. Tissue-engineering involves the manipulation of cells using in vitro techniques to create a composite tissue, which could then be implanted in vivo. Corneal equivalents have been reconstructed from corneal cell lines. They already have their potential uses in the biomedical world: as replacements for animals in toxicology testing and pharmacological studies, as well as in basic research into cell-cell and cell-matrix interactions of corneal wound healing. Current research is ongoing to determine if the bio-engineered cornea will have a role in corneal transplant surgery.