Method of molding a polyvinyl alcohol contact lens
AssigneeBiomaterials Universe, Inc.
InventorsSuong-Hyu Hyon, Yoshito Ikada
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Abstract
A soft contact lens of PVA having a tensile strength of not less than 10 kg/cm.sup.2, 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.times.10.sup.-11 cm.sup.3.(STP).cm/cm.sup.2.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.
Claims5
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.degree. 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.
Dependencies are inferred from the claim text.