Particulate hydroperoxidized poly-N-vinyl lactam, its preparation and use thereof

Claim 1

A transparent contact lens formed of a hydrogel composition consisting essentially of (A) a graft copolymer, wherein said copolymer is formed from about 1 to about 80 weight percent of a particulate hydroperoxidized derivative of a poly-N-vinyl lactam containing units of the formula ##STR7## where R is alkylene of 2 to 8 carbon atoms, n is about 40 to about 4000, and wherein said derivative contains an average of between about 0.5 to about 20 hydroperoxy equivalents per mole of poly-N-vinyl lactam; said derivative being the result of the process comprising contacting a particulate polymer having units of formula I with ozone, from about 99 to about 20 weight percent of one or more hydrophilic or hydrophobic vinylic monomer, with the proviso that at least one-half of said vinylic monomer is a hydrophilic monomer, in the further presence or absence of up to about 5 weight percent of a crosslinking agent, and (B) swollen with a physiologically acceptable aqueous medium, such that the amount of (B) is between about 20 and 80 weight percent of the total of (A) and (B).