Method for making UV-absorbing ophthalmic lenses

A method for producing UV-absorbing silicone hydrogel contact lenses which have an UVB transmittance of about 10% or less between 280 and 315 nanometers, an UVA transmittance of about 30% or less between 316 and 380 nanometers, and an average violet transmittance of about 70% or less between 381 nm and 440 nm, the method comprising the steps of:

• (1) providing a mold for making a soft contact lens, wherein the mold has a first mold half with a first molding surface defining the anterior surface of a contact lens and a second mold half with a second molding surface defining the posterior surface of the contact lens, wherein said first and second mold halves are configured to receive each other such that a cavity is formed between said first and second molding surfaces;
• (2) introducing a UV-absorbing pre-polymerization mixture of lens-forming materials into the cavity, wherein the pre-polymerization mixture comprises
• (a) at least one hydrophilic vinylic monomer,
• (b) at least one siloxane-containing vinylic monomer,
• (c) at least one polysiloxane crosslinker with two or more ethylenically-unsaturated groups,
• (d) a first UV-absorbing vinylic monomer and a second UV-absorbing vinylic monomer, wherein the first UV-absorbing vinylic monomer absorbs UV radiation and high-energy-violet-light radiation of from 380 nm to 440 nm, wherein the second UV-absorbing vinylic monomer absorbs UV radiation, wherein the first and second vinylic monomers are present in the UV-absorbing pre-polymerization mixture in an amount sufficient to render a contact lens formed from the curing of the UV-absorbing pre-polymerization mixture an ability of blocking at least 90% of UVB light between 280 and 315 nanometers, at least 70% of UVA light between 316 and 380 nanometers, and at least 30% of high-energy violet light between 381 nm and 440 nm,
• (e) at least one visibility-tinting agent, and
• (f) from about 0.05% to about 1.5% by weight of at least one germanium-based Norrish Type I photoinitiator capable of initiating a free-radical polymerization under irradiation with a light source including a light in the region of about 380 to about 550 nm;
• and
• (3) irradiating the pre-polymerization mixture in the mold with a light in a region of from 380 to 550 nm and crosslinking the lens-forming materials to form an UV-absorbing silicone hydrogel contact lens,
• wherein the formed UV-absorbing silicone hydrogel contact lens is substantially free of internal stress and has an UVB transmittance of about 10% or less between 280 and 315 nanometers, an UVA transmittance of about 30% or less between 316 and 380 nanometers, and an average violet transmittance of about 70% or less between 381 nm and 440 nm.