1,221,334. Contact lenses. DEUTSCHE AKADEMIE DER WISSENSCHAFTEN ZU BERLIN. May 7, 1968, No.21619/68. Heading G2J. A process for the production of contact lenses from plastic mouldings or silica glasses is carried out in two operations. An unpolished lens blank produced from an organic polymer or silica glass is mounted on a support such as a meniscus-like indentation on the upper surface of a rotable truncated core, and a second layer consisting of a solution of a hydrophilic polymer added dropwise from a pipette centred vertically above the lens blank at an optimum distance from it of between 3 and 10 cm. The solvent is a physiologically compatable liquid such as acetone and contains in it a small proportion of a flow promoting agent which may be an alcohol or a mono-ether of a diol which also acts to improve the wetting properties of the flexible layer. The diopter value of the lens may be varied by control of the number of coats of polymer given to either the convex or concave side of the optically stable core. Increasingly positive diopter values may be obtained by an over-application to the convex side while increasingly negative values may be obtained by an over-application to the concave side.
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