The Holy Grail of contact lens users is a material so biocompatible that it can be worn indefinitely.
Several factors are in play here.
The first is the resistance of the lens to the deposition of protein from the eye, which can lead to bacterial growth and infection. The second is the binding of water by the lens, which allows for increased flow of oxygen, essential for normal eye function. One approach to solving this problem is to modify the surface of the lens to display molecules that are similar to those found on the surfaces of cells of the eye. This requires knowledge of the biochemistry of the surface of the corneal cells, the identification of compatible molecules for placement onto the lens surface, and the development of chemical schemes to introduce those molecules onto the surface of the lens in a controlled manner. Bertozzi's research group has accomplished this.