Process for producing an ocular lens having a highly hydrophilic lens surface and ocular lens produced by the process

#The present invention relates to a process for producing an ocular lens having a highly hydrophilic lens surface and an ocular lens produced by the process. Particularly, it relates to a process to impart high hydrophilicity to an ocular lens surface without employing a complicated treatment step, and an ocular lens having a highly hydrophilic surface produced by such a process.

#In recent years, a hard contact lens comprising a copolymer of e.g. siloxanyl methacrylate or a fluoroalkyl methacrylate, wherein oxygen permeability is imparted to its material itself so as not to inhibit metabolism of the cornea, has been used practically. However, such an oxygen permeable hard contact lens has high water repellency on its surface, the tear and the lens surface are not compatible well when the lens is put on the eye, and the tear tends to be repelled on the lens surface, and accordingly the user may feel uncomfortableness such as feeling of dryness. Further, the tear that presents between the lens and the cornea tends to be hardly changed, whereby lipid components in the tear are likely to deposit on the lens surface, thus impairing optical properties of the lens, or causing cloudiness or blur in the field of view, and further, there is such inherent fear that stain on the lens surface may impair the cornea.

#On the other hand, a soft contact lens, which is flexible itself, which is likely to fit the cornea, and which provides favorable feeling, has been known. As many of such soft contact lenses comprise a water-absorptive material which absorbs water and becomes flexible, there are various problems such as generation of bacteria or fungi inside the lens. Thus, a non water-absorptive soft contact lens comprising a flexible material which absorbs and contains substantially no water, which can prevent generation of e.g. bacteria inside the lens, has been developed. However, even with respect to such a non water-absorptive soft contact lens, as the lens surface is water repellent, there are problems similar to those of the oxygen permeable hard contact lens, and further, due to the flexibility of the lens, such a problem that the lens is adsorbed on the cornea has newly arisen.

#To 100 parts by weight of a composition for a non water-absorptive contact lens as identified in the following Table 2, 0.8 part by weight of ethylene glycol dimethacrylate as a crosslinking agent and 0.2 part by weight of 2-hydroxy-2-methyl-1-phenyl-propane-1-one (trade name: Darocure 1173) as a polymerization initiator were added to prepare a monomer mixed liquid. Further, as a mold, a mold made of a non-crosslinked polyacrylic acid, consisting of a convex mold and a concave mold (for preparation of a test sample in the form of a disc plate having a diameter of 20 mm and a thickness of 0.3 mm: PAAc mold) was prepared.

#Then, the monomer mixed liquid was injected into the molding cavity of the mold, the convex and concave molds were coupled with each other, and the coupled mold was held for 30 minutes. After the holding, the mold was irradiated with ultraviolet rays at room temperature at an irradiation intensity of 11 mW/cm2 for 15 minutes by means of an ultraviolet ray irradiation system (UX0302-03, manufactured by Eye Graphics Co., Ltd., measurement wavelength: 365 nm) to polymerize the monomer mixed liquid in the mold. After completion of the polymerization, since the obtained polymer was attached to the mold, the mold was immersed in salt solution to dissolve the mold made of a non-crosslinked polyacrylic acid, whereby the disc plate-shape polymer was taken out. The polymer taken out was washed with solvents in the order of water, 2-propanol, methanol and water, to obtain a test sample 1.

#The same monomer mixed liquid used in Example 1 was prepared, and as a mold, a mold made of polypropylene, consisting of a convex mold and a concave mold (for preparation of a test sample in the form of a disc plate having a diameter of 20 mm and a thickness of 0.3 mm, PP mold) was prepared. Using this mold, polymerization of the monomer mixed liquid was carried out in the same manner under the same conditions as in Example 1. After completion of the polymerization, the polymer attached to the mold was forcibly detached by external force, and the same washing treatment as in Example 1 was carried out to obtain a test sample 2.