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Concentric annular ring lens designs for astigmatism

  • US 5,652,638 A
  • Filed: 05/04/1995
  • Issued: 07/29/1997
  • Est. Priority Date: 05/04/1995
  • Status: Expired due to Term
First Claim
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1. A multifocus, concentric annular ring lens for astigmatic patients comprising:

  • a. said lens having a front surface and an opposite back surface;

    b. one of the front and back surfaces defines a toric curve;

    c. the other of the front and back surfaces defines a plurality of spherical concentric annular rings having at least one first spherical annular ring corresponding to the patient'"'"'s basic distance spherical prescription Rx, and at least one second spherical annular ring corresponding to the patient'"'"'s basic cylindrical prescription Rx, such that the multifocus toric lens is rotationally desensitized because of the enhanced depth-of-field provided by the plurality of concentric annular rings;

    wherein the difference between the optical powers of the first and second spherical annular rings is less than 2.0 diopters.

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