TINTED HYDROGEL PLASTIC ARTICLES AND METHOD OF TINTING THEM

摘要

A hydrogel plastic article such as a soft contact lens is tinted by a water-insoluble vat dye which is physically locked into the hydrogel polymer as aggregates that are not individually discernible to the naked eye, and do not protrude beyond the surface of the article. In a soft contact lens, the aggregates may be concentrated near its convex face and only in an area approximating a human iris.