Abstract: An aqueous contact lens storage solution comprises a viscoelastic rheology modifier; and not more than 0.3% w/v of an alkali metal salt; the solution has a pH of between 6.0 and 8.0 and an osmolality of between 100 and 400 mOsm/kg, and the solution has viscoelastic properties, even if heat sterilized at 121° C. for at least 15 minutes. The viscoelastic rheology modifier may be selected from the following acids or their alkali metal salts: hyaluronic acid, poly (acrylic acid), crosslinked poly (acrylic acid), poly (methacrylic acid), carboxymethyl cellulose, alginic acid and mixtures thereof. The alkali metal salt may be present in an amount of from 0.01% to 0.

Abstract: A graft polymer obtainable by grafting a polymer substrate with a compound of formula (I), in which the groups R are the same or different and each is a straight or branched C.sub.1 -C.sub.4 alkyl group; X is an aryl group or a straight or branched C.sub.1 -C.sub.20 alkylene group, optionally containing one or more carbon-carbon double or triple bonds, ether linkages or aryl groups; the aryl groups being unsubstituted or substituted by one or more C.sub.1-4 alkyl groups; n is from 2 to 4; and A is a reactive group, is useful as a biocompatible material in contact lenses, biomedical devices and blood-containing devices. In a preferred embodiment A is a polymerizable group and the graft polymer is produced by radical initiated polymerization of the compound of formula (I) on the substrate which is initiated by a radical-forming group on the substrate.