Polymers in modern ophthalmic implants—Historical background and recent advances

Cataract surgery is the most frequently performed surgical intervention, pursued by replacement of the opacified natural lens by a polymeric intraocular lens (IOL). This paper, based on an exhaustive number of scientific references, provides a brief simplified discussion of the surgical advances for cataract treatment, and is mainly focused on the process of IOL discovery, engineering and development. The performances of the polymer materials, used for the IOLs fabrication are discussed in a comparative way, and their properties, such as handling during surgery, biocompatibility, rate of some post-surgical complications (e.g. Posterior Capsular Opacification) and optical properties, are considered.
Special attention is paid on the basic scientific approaches for engineering and modification of the IOL surface and bulk properties. Polymer coating techniques like ‘grafting onto’ and ‘grafting from’ are discussed and exemplified by a variety of coating compositions and performances.
In another part of the review, modification techniques concerning optimization of the bulk properties of the polymer lens are also discussed and synthetic approaches such as copolymerization and nanocomposite formation are considered. A perspective aspect of this discussion concerns improvement of the performance of the main polymer by the incorporation of in situ formed or preformed nanoparticles.
The most attractive perspectives concerning the improvement of the IOL properties by chemical modification approaches are described.