Contact lenses have been used commercially to improve vision since the 1950s. The first contact lenses were made of hard materials. Although these lenses are currently used, they are not widely used due to their poor initial comfort and their relatively low permeability to oxygen. Later developments in the field gave rise to soft contact lenses, based upon hydrogels. Many users find soft lenses are more comfortable, and increased comfort levels allow soft contact lens users to wear their lenses for longer hours than users of hard contact lenses.
Another class of available contact lenses is silicone hydrogel contact lenses. Silicone-containing components are combined with conventional hydrogel components to form silicone hydrogels which display increased oxygen permeability compared to conventional hydrogels. However, some silicone hydrogels display undesirably high contact angles and protein uptake compared to conventional hydrogel lenses.
Various compounds have been disclosed as suitable for treating preformed silicone hydrogel contact lenses including surface active segmented block copolymers, substantially water-soluble silicone-containing surfactants, functionalized hybrid PDMS/polar amphipathic copolymer block systems, including polydimethylsiloxane-PVP block copolymers and (meth)acrylated polyvinylpyrrolidone. U.S. Patent Appln. Ser. No. 2011/0275734 is directed to “non-reactive, hydrophilic polymers having terminal siloxanes,” which have linear or branched hydrophilic segments. There remains a need for methods for improving the properties of contact lenses and particularly silicone hydrogel contact lenses.