| abstract |
OBJECT OF THE INVENTION IS A METHOD OF FORMING COLOR EFFECTS IN HYDROGEL CONTACT LENSES AND OPHTHALMIC PROSTHESES, WHEREIN THE COLORED PATTERN IS FORMED BETWEEN AT LEAST TWO TRANSPARENT HYDROGEL LAYERS, BOUND TOGETHER BY POLYMERIZING BETWEEN THEM A MONOMER MIXUTRE FORMING THE SAME OR SIMILAR HYDROGEL. A HOMOGENEOUS TRANSPARENT THIN COVERING LAYER OF HYDROGEL IS FIRST FORMED ON A REGULAR SURFACE OF A SMOOTH PAD. THE DESIRED COLORED PATTERN IS THEN FORMED BETWEEN IT AND THE CONCAVE SURFACE OF A LENS OR THAT OF AN OPHTHALMIC PROSTHESIS, BEING EITHER LAID BETWEEN THEM AS A THIN FOIL OR CREATED ON EITHER THE SAID CONCAVE SURFACE OR SAID COVERING LAYER, THE LAST MENTIONED EMBODIMENT BEING PREFERRED. THE BOND BETWEEN THE LENS OR PROSTHESIS AND THE COVERING LAYER IS REALIZED BY PUTTING A DROP OF INITATED MONOMER MIXTURE BETWEEN THEM AND PRESSING THEM SLIGHTLY TOGETHER SO THAT THE EXCESS OF THE MONOMER MIXTURE IS EXPRESSED. THE COLORED PATTERN IS PREFERABLY FORMED USING COLORS, DYESTUFFS OR PIGMENTS WHICH ARE INSOLUBLE IN WATER AND IN MONOMER MIXTURE. THE FINISHED LENS OR PROSTHESIS IS THEN REMOVED FROM THE PAD BY SWELLING THE WHOLE IN A SWELLING LIQUID SUCH AS WATER OR ALCOHOL AND KEPT IN STERILE PHYSIOLOGIC SOLUTION. |