Method of molding a polyvinyl alcohol contact lens

• US 4,874,562 A
• Filed: 09/30/1987
• Issued: 10/17/1989
• Est. Priority Date: 02/13/1986
• Status: Expired due to Fees

• Current Assignee: Bio-Materials Univers Company
• Original Assignee: Bio-Materials Univers Company
• Inventors: Ikada, Yoshito, Hyon, Suong-Hyu
• Primary Examiner(s): Lowe, James
• Application Number:
  US07/117,171
• Time in Patent Office: 748 Days
• Field of Search: 264/2.6, 264/1.1, 264/1.4, 351/160 H
• US Class Current: 264/1.36
• CPC Class Codes: B29D 11/00076 enabling passage of fluids, e.g. oxygen, tears, between the area under the lens and the lens exterior
• CPC Class Codes: C08L 29/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
• CPC Class Codes: G02B 1/043 Contact lenses
• CPC Class Codes: G02C 7/04 Contact lenses for the eyes disinfection or sterilisation of contact lenses A61L12/00

Abstract

A soft contact lens of PVA having a tensile strength of not less than 10 kg/cm², a water content ranging from 40 to 95% by weight, a visible light transparency of not less than 90%, and an oxygen permeability of not less than 30×10^-11 cm³.(STP).cm/cm².sec.mmHg. This soft contact lens can be prepared by forming a solution of PVA in a mixed solvent of water and an organic solvent, pouring the PVA solution in a mold having a shape of contact lens, and crystallizing at a temperature of not more than ordinary temperature. The soft contact lens has a high mechanical strength, high water content, high transparency and high oxygen permeability.

Claims

1. A method of manufacturing a soft contact lens, comprising forming a solution of poly(vinyl alcohol) in a mixed solvent of water and an organic solvent in a weight ratio of water to organic solvent of 90:

10 to 10;

90, pouring the solution in a mold having a shape of a contact lens, crystallizing the poly(vinyl alcohol) at a temperature of not more than 0°

C., taking the crystallized poly(vinyl alcohol) out of the mold, and then replacing the organic solvent in the crystallized poly(vinyl alcohol) with water.

2. The method of claim 1, wherein the organic solvents are missible withwater.

3. The method of claim 1, wherein the concentration of poly(vinyl alcohol) in the poly(vinyl alcohol) solution is in the range of 2 to 30% by weight.

4. The method of claim 1, wherein the organic solvent is selected from the group consisting of dimethyl sulfoxidide, glycerine, ethylene glycol, propylene glycol, triethylene glycol, dimethylformamide, methyl alcohol, ethyl alcohol, acetone, tetrahydrofuran, aminoethyl alcohol, phenol, n-propyl alcohol and iso-propyl alcohol.

5. The method of claim 1, wherein the crystallized poly(vinyl alcohol) is crosslinked by irradiation with electron beams or radioactive rays.