The original function of polymeric contact lenses was as a vision aid. Recent developments in materials and methods, have improved their properties to fulfil the requirements of oculists and patients, and include lenses to protect the eye against photochemical and physical stresses of the environment, i.e. against the UV part of the troposphere's solar radiation and against photo-oxidants from the polluted atmosphere. This paper deals with an interdisciplinary topic. Topics covered include monomers used for the construction of polymeric contact lenses, the formation of aggressive photo-oxidants, photo-oxidative damage to the eye and the polymeric lens, and their protection by UV absorbers and hindered amine stabilizers. Activity mechanisms of photostabilizers, and examples of monomeric structures suitable for copolymerization with the monomers used to make contact lenses to produce physically permanent (polymer-bound) photostabilizers are explained.
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