Method for producing wettable silicone hydrogel contact lenses

A method for producing coated silicone hydrogel contact lenses which are optically clear and have an oxygen permeability of at least about 50 barrers, wherein no ophthalmically incompatible organic solvent is used in the method, wherein the method comprises the steps of:

• (1) introducing a polymerizable composition into a lens mold, wherein the polymerizable composition comprises (a) from about 35% to about 60% at least one hydrophilized polysiloxane vinylic crosslinker relative to the total amount of all polymerizable components, (b) hydroxyethyl methacrylate, (c) ethoxyethyl (meth)acrylate, (d) from about 2% to about 10% by weight of at least one carboxyl-containing (meth)acryloxy monomer relative to the total amount of all polymerizable components, and (e) at least one free-radical initiator, wherein the polymerizable composition is formulated in an ophthalmically compatible organic solvent selected from the group consisting of propylene glycol, a polyethyleneglycol having a molecular weight of about 400 Daltons or less, wherein the sum of the amounts of components (a) to (e) is at least 96 by weight, relative to the total amount of all polymerizable components in the polymerizable composition, wherein the sum of the amounts of components of components (b) and (c) is from about 35% to about 60% by weight relative to the total amount of all polymerizable components in the polymerizable composition;
• (2) curing thermally or actinically the polymerizable composition in the lens mold to form a dry lens precursor comprising a bulk silicone hydrogel material that comprises carboxyl groups carboxyl groups on and/or near the surface of the bulk silicone hydrogel material;
• and
• (3) forming a coated silicone hydrogel contact lens by heating the dry lens precursor obtained in step (2) directly in an aqueous solution having a pH from about 6.8 to about 8.5 and including at least one water-soluble, thermally-crosslinkable hydrophilic polymeric material at a temperature from about 60° C. to about 140° C., wherein the coated silicone hydrogel contact lens comprises the bulk silicone hydrogel material and a layer of a crosslinked hydrophilic polymeric material that is covalently attached onto the bulk silicone hydrogel material through the carboxyl groups on and/or near the surface of the bulk silicone hydrogel material,
• wherein the coated silicone hydrogel contact lens exhibits a water-break-up-time (WBUT) of at least about 10 seconds and an oxygen permeability of at least about 50 barrers.