Colored contact lenses and method of making same

A method of producing a soft hydrogel colored contact lens comprising:

• preparing a dispersion by:
• dissolving in an organic solvent from 1 to 90% by weight of a polymerized thermoplastic material in the solvent which material is compatible with the monomer material to be used in the lens so as to produce a resin system of the thermoplastic material in the organic solvent,
• dispersing in the resulting resin system from about 1 to about 80% by weight of the resin system of a coloring material which is insoluble in the monomer material to be used to form the lens so as to form a dispersion, and
• incorporating in said dispersion an amount of a thixotropic agent sufficient to prevent the dispersion from running when applied on the surface of the mold,
• applying the resulting dispersion produced above to imprint an iris simulating pattern on a surface of a casting mold,
• evaporating the organic solvent from the dispersion,
• introducing a monomeric lens forming liquid in said mold in contact with said imprinted surface wherein said monomer lens forming liquid comprises a hydrophilic monomer capable of forming a soft hydrogel lens,
• polymerizing said liquid to produce a lens blank having a colored pattern impregnated in said blank, adjacent an optical surface thereof and
• hydrating the resulting lens.