Patent ID: 7744785

Claim:
A method for making silicone-hydrogel contact lenses, comprising steps of: obtaining a polymerizable fluid composition including a siloxane-containing macromer with ethylenically unsaturated group(s), at least one hydrophilic vinylic monomer, a free radical initiator, and an organonitroxide, wherein ratio of percentage by weight of the organonitroxide to the radical initiator in the polymerizable fluid composition is selected to enable the polymerization fluid composition to be cured at an elevated temperature to form rods which are substantially free of defects including cracks and voids and have consistent properties selected from the group consisting of oxygen permeability, ion permeability, water content, elastic modulus, elongation, and combination thereof, wherein the organonitrioxide is a compound having the formula of in which R 1 and R 2 independently H, an alkyl group, a cycloalkyl group, an arenyl group, a heterocyclic group, or an aryl group, R 3 is an alkyl group, a cycloalkyl group, an arenyl group, a heterocyclic group, or an aryl group, R 3 and R 2 or R 1 and R 2 may be joined together to form a cyclic ring structure that may have fused with it another saturated or aromatic ring, each of R 1 , R 2 , or R 3 may be substituted by at least one member of the group consisting of hydroxyl group, sulfonate group, sulfate group, carboxylate group, amino group, ammonium group, alkoxy group, aryloxy group, silyl group, boryl group, phosphino group, thio group, seleno group, and combinations thereof; filling one or more tubes with the polymerizable fluid composition; curing the polymerizable fluid composition at the elevated temperature in the tubes to form a polymer in a form of rod which is free of cracks and voids; stripping away the tubes from the polymer; and lathing the polymer to produce the contact lenses having an oxygen permeability of at least about 40 barres, a modulus of about 1.5 MPa or less, and a water content of at least about 15% by weight when fully hydrated.