Method for cast molding contact lenses

摘要

The invention provide a method for cast-molding hydrogel contact lenses, especially silicone hydrogel contact lenses by using plastic molds of a poly(cycloalkylene-dialkylene terephthalate) copolymer. These plastic molds do not need to be degassed and stored in an oxygen-free atmosphere (e.g., N2 or Ar) before being used for cast-molding silicone hydrogel contact lenses in the absence of oxygen and resultant silicone hydrogel lenses can still have relatively high ion permeability and relatively low variation in targeted optical power, compared with silicone hydrogel lenses made from a conventional mold material, such as polypropylene. The invention also provides plastic molds for cast-molding silicone hydrogel contact lenses.

主权项

1. A method of cast molding contact lenses in the presence of oxygen, wherein the contact lenses have significantly reduced lathe marks observed using a microscopic contrast technique known as Reflective Differential Interference Contrast (RDIC), relative to a control silicone hydrogel lens obtained by cast molding of the silicone hydrogel lens formulation in a mold of polypropylene, comprising the steps of:
obtaining a mold to form a contact lens, wherein the mold includes a first mold half having a first molding surface in contact with the lens-forming material and a second mold half having a second molding surface in contact with the lens-forming material, wherein said first mold half and said second mold half are configured to receive each other such that the cavity is formed between said first and second molding surfaces, wherein the mold is made of a poly(cycloalkylene-dialkylene terephthalate) copolymer, wherein the poly(cycloalkylene-dialkylene terephthalate) copolymer comprises repeating units from at least 90 mole percent terephthalic acid and at least 90 mole percent of a C6-C24 cycloaliphatic diol, based on 100 mole percent dicarboxylic acid and 100 mole percent diol, wherein the mold is not degassed and stored in an oxygen-free atmosphere; introducing a lens forming material into the mold, wherein the lens forming material is a silicone hydrogel lens-forming material comprising an organic solvent and at least one polymerizable component selected from the group consisting of a silicon-containing monomer, a silicone-containing macromer, a silicone-containing prepolymer, and a mixture thereof; closing the mold and swelling locally the mold at and near the first and second molding surfaces by waiting for at least about 5 minutes before polymerization of the lens forming material in the mold; and polymerizing the lens forming material in the mold with localized and limited swelling at or near the molding surfaces thereof to obtain a silicone hydrogel contact lens having an increased ion permeability and the significantly reduced lathe marks.