Patent ID: 8357771

Claim:
A soft hydrogel contact lens, which is obtained by polymerization of a fluid composition, wherein the composition comprises at least one first prepolymer having multiple first propagating groups each capable of undergoing photo-induced step-growth polymerization in the presence of a step-growth-crosslinking agent having two or more second propagating groups each co-reactive with one of the first propagating group in a photo-induced step-growth polymerization, provided that the composition is substantially free of any vinylic monomer, wherein either of the first and second propagating groups are thiol groups and the other are ene-containing groups of formula (II) or (III) in which R 4 -R 9 , independent of each other, are hydrogen, C 1 -C 10 alkene divalent radical, C 1 -C 10 alkyl, or —(R 18 ) a —(X 1 ) b —R 19 in which a and b independent of each other is zero or 1, R 18 is C 1 -C 10 alkene divalent radical, X 1 is an ether linkage, a urethane linkage, a urea linkage, an ester linkage, an amide linkage, or carbonyl, R 19 is hydrogen, a single bond, amino group, carboxylic group, hydroxyl group, carbonyl group, C 1 -C 12 aminoalkyl group, C 1 -C 18 alkylaminoalkyl group, C 1 -C 18 carboxyalkyl group, C 1 -C 18 hydroxyalkyl group, C 1 -C 18 alkylalkoxy group, C 1 -C 12 aminoalkoxy group, C 1 -C 18 alkylaminoalkoxy group, C 1 -C 18 carboxyalkoxy group, or C 1 -C 18 hydroxyalkoxy group, optionally R 4 and R 9 are linked through an alkene divalent radical to form a cyclic ring, provided that at least one of R 4 -R 9 are divalent radicals; n and m independent of each other are integer number from 0 to 9, provided that the sum of n and m is an integer number from 2 to 9; R 10 -R 17 , independent of each other, are hydrogen, C 1 -C 10 alkene divalent radical, C 1 -C 10 alkyl, or —(R 18 ) a —(X 1 ) b —R 19 in which R 18 , X 1 , R 19 , a and b are defined as above, p is an integer number from 1 to 3, provided that only one or two of R 10 -R 17 are divalent radicals.