Contact lens casting method
First Claim
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1. The method of making a contact lens of an ophthalmic quality resin comprising:
- preparing a casting precursor by adding to the resin an extractable, non-reactive, miscible diluent in an amount precontrolled according to a subsequent volume reduction desired of the precursor after casting;
filling a mold casting cavity of predetermined fixed shape and size with said precursor;
at least partially curing the thus cast precursor in situ;
removing the resulting cast lens from said cavity; and
extracting said diluent from the cast lens to shrink the lens to a size smaller than that of said casting cavity, said size reduction corresponding to said amount of said diluent added to said precursor.
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Abstract
Producing from a single contact lens casting mold, lenses of a number of different sizes by including in the casting precursor for each lens, a controlled amount of an extractable diluent of low volatility which is extracted after casting to cause the resulting lens to shrink a calculable amount. Variations in amounts are used to produce corresponding variations in sizes of cast and extracted lenses.
47 Citations
12 Claims
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1. The method of making a contact lens of an ophthalmic quality resin comprising:
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preparing a casting precursor by adding to the resin an extractable, non-reactive, miscible diluent in an amount precontrolled according to a subsequent volume reduction desired of the precursor after casting; filling a mold casting cavity of predetermined fixed shape and size with said precursor; at least partially curing the thus cast precursor in situ; removing the resulting cast lens from said cavity; and extracting said diluent from the cast lens to shrink the lens to a size smaller than that of said casting cavity, said size reduction corresponding to said amount of said diluent added to said precursor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification