Silicone hydrogel lens with a crosslinked hydrophilic coating

#Soft silicone hydrogel contact lenses are increasingly becoming popular because of their high oxygen permeability and comfort. But, a silicone hydrogel material typically has a surface, or at least some areas of its surface, which is hydrophobic (non-wettable) and susceptible to adsorbing lipids or proteins from the ocular environment and may adhere to the eye. Thus, a silicone hydrogel contact lens will generally require a surface modification.

#A known approach for modifying the hydrophilicity of a relatively hydrophobic contact lens material is through the use of a plasma treatment, for example, commercial lenses such as Focus NIGHT & DAY™ and O2OPTIX™ (CIBA VISION), and PUREVISION™ (Bausch & Lomb) utilize this approach in their production processes. Advantages of a plasma coating, such as, e.g., those may be found with Focus NIGHT & DAY™, are its durability, relatively high hydrophilicity/wettability), and low susceptibility to lipid and protein deposition and adsorption. But, plasma treatment of silicone hydrogel contact lenses may not be cost effective, because the preformed contact lenses must typically be dried before plasma treatment and because of relative high capital investment associated with plasma treatment equipment.

#Another approach for modifying the surface hydrophilicity of a silicone hydrogel contact lens is the incorporation of wetting agents (hydrophilic polymers) into a lens formulation for making the silicone hydrogel contact lens as proposed in U.S. Pat. Nos. 6,367,929, 6,822,016, 7,052,131, and 7,249,848. This method may not require additional posterior processes for modifying the surface hydrophilicity of the lens after cast-molding of silicone hydrogel contact lenses. However, wetting agents may not be compatible with the silicone components in the lens formulation and the incompatibility may impart haziness to the resultant lenses. Further, such surface treatment may be susceptible to lipid deposition and adsorption. In addition, such surface treatment may not provide a durable surface for extended wear purposes.

#Reference now will be made in detail to the embodiments of the invention. It will be apparent to those skilled in the art that various modifications, variations and combinations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications, variations and combinations as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.

#Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein and the laboratory procedures are well known and commonly employed in the art. Conventional methods are used for these procedures, such as those provided in the art and various general references. Where a term is provided in the singular, the inventors also contemplate the plural of that term. The nomenclature used herein and the laboratory procedures described below are those well known and commonly employed in the art.

#A “silicone hydrogel contact lens” refers to a contact lens comprising a silicone hydrogel material. A “silicone hydrogel” refers to a silicone-containing polymeric material which can absorb at least 10 percent by weight of water when it is fully hydrated and is obtained by copolymerization of a polymerizable composition comprising at least one silicone-containing vinylic monomer or at least one silicone-containing vinylic macromer or at least one silicone-containing prepolymer having ethylenically unsaturated groups.