Multifocal Lens Having a Progressive Optical Power Region and a Discontinuity

Abstract

Embodiments of the present invention relate to a multifocal lens having a diffractive optical power region and a progressive optical power region. Embodiments of the present invention provide for the proper alignment and positioning of each of these regions, the amount of optical power provided by each of the regions, the optical design of the progressive optical power region, and the size and shape of each of the regions. The combination of these design parameters allows for an optical design having less unwanted astigmatism and distortion as well as both a wider channel width and a shorter channel length compared to conventional PALs. Embodiments of the present invention may also provide a new, inventive far-intermediate distance zone and may further provide for increased vertical stability of vision within a zone of the lens.

1 . An ophthalmic lens having a far distance zone, comprising:
 a diffractive optical power region for providing a first incremental add optical power;   a discontinuity located between the far distance zone and said diffractive optical power region; and   a progressive optical power region for providing a second incremental add power, wherein at least a portion of said diffractive optical power region and said progressive optical power region are in optical communication such that said first incremental add power and said second incremental add power together provide a near distance add power for a user.   
     
     
         2 . The ophthalmic lens of  claim 1 , further comprising:
 a plateau of optical power located in a portion of said progressive optical power region for providing vertical stability of vision in an intermediate distance zone of the ophthalmic lens.   
     
     
         3 . The ophthalmic lens of  claim 2 , wherein said plateau of optical power has a vertical length of approximately 1 millimeter to approximately 3 millimeters or greater. 
     
     
         4 . The ophthalmic lens of  claim 2 , wherein said plateau of optical power has a vertical length of approximately 2 millimeter to approximately 6 millimeters or greater. 
     
     
         5 . The ophthalmic lens of  claim 1 , further comprising:
 a blend zone for blending optical power across at least a portion of said discontinuity.   
     
     
         6 . The ophthalmic lens of  claim 5 , wherein at least a portion of said blend zone has a width of approximately 2.0 millimeters or less. 
     
     
         7 . The ophthalmic lens of  claim 1 , wherein the ophthalmic lens has an intermediate distance zone and said intermediate distance zone has an add power that is between approximately 45% and approximately 55% of said near distance add power. 
     
     
         8 . The ophthalmic lens of  claim 1 , wherein the lens has a fitting point, and wherein the top edge of said diffractive optical power region is located between approximately 3 millimeters and approximately 4 millimeters below said fitting point, and wherein said progressive optical power region starts between approximately 4 millimeters and approximately 8 millimeters from the top edge of said diffractive optical power region. 
     
     
         9 . The ophthalmic lens of  claim 1 , wherein said discontinuity is caused by a step in optical power. 
     
     
         10 . The ophthalmic lens of  claim 9 , wherein said step in optical power is a step up in optical power of at least approximately +0.12 D. 
     
     
         11 . The ophthalmic lens of  claim 1 , wherein said diffractive optical power region is located on a surface of the lens or buried within the lens. 
     
     
         12 . The ophthalmic lens of  claim 1 , wherein said progressive optical power region is located on a surface of the lens or buried within the lens. 
     
     
         13 . The ophthalmic lens of  claim 1 , wherein said progressive optical power region comprises a progressive optical power surface, and wherein said progressive optical power surface is generated by one of free-forming, molding, or surface casting. 
     
     
         14 . The ophthalmic lens of  claim 1 , wherein said diffractive optical power region is generated by one of free forming a surface of the lens, molding a surface of the lens, or burying a surface within the lens. 
     
     
         15 . The ophthalmic lens of  claim 1 , wherein the lens comprises an upper far-intermediate distance zone, and wherein said upper far-intermediate distance zone has an add power that is between approximately 20% and approximately 44% of said near distance add power. 
     
     
         16 . The ophthalmic lens of  claim 1 , wherein the lens has a fitting point, and wherein the top edge of said diffractive optical power region is located between approximately 2 millimeters and approximately 5 millimeters below said fitting point, and wherein said progressive optical power region starts between approximately 4 millimeters and approximately 8 millimeters from the top edge of said diffractive optical power region. 
     
     
         17 . The ophthalmic lens of  claim 1 , wherein the lens has a near distance zone, and wherein the optical power contributed by said progressive optical power region decreases after said near distance zone for providing a lower far-intermediate zone. 
     
     
         18 . A lens comprising:
 a first layer having a first index of refraction, wherein the first layer has a first curvature and a second curvature, wherein the second curvature provides a single optical power; and   a second layer having a second index of refraction different from the first index of refraction, wherein the second layer has a first curvature and a second curvature, wherein the second curvature of the second layer provides a progression of optical power and is in optical communication with the second curvature of the first layer for providing a combined optical power for correcting near distance vision.   
     
     
         19 . The lens of  claim 18 , wherein the single optical power is a spherical optical power. 
     
     
         20 . The lens of  claim 18 , wherein the second curvature of the second layer is formed on an external surface of the lens. 
     
     
         21 . The lens of  claim 18 , wherein the second curvature of the first layer begins 4 millimeters below a fitting point of the lens. 
     
     
         22 . The lens of  claim 18 , wherein there is a discontinuity in the optical power of the lens between the first and second curvatures of the first layer. 
     
     
         23 . A lens, comprising:
 a first layer having a first index of refraction, wherein the first layer comprises a far distance zone and a first optical element; and   a second layer having a second index of refraction different from the first index of refraction, wherein the second layer comprises a far distance zone and a second optical element,   wherein the first optical element comprises a substantially spherical optical power region, the substantially spherical optical power region contributing a first portion of a total near distance add power of the lens,   wherein an optical discontinuity occurs at a boundary of the first optical element and the far distance zone of the first layer due to a step-up in optical power between the first optical element and the far distance zone of the first layer,   wherein the first optical element is located 4 millimeters below a fitting point of the lens,   wherein the second optical element comprises a progressive optical power region, the progressive optical power region contributing a second portion of the total near distance add power of the lens, and   wherein the first and second optical elements are in optical communication such that the first portion of the total near distance add power of the lens and the second portion of the total near distance add power of the lens are combined to provide the total near distance add power of the lens.   
     
     
         24 . The lens of  claim 23 , wherein the first and second optical elements are aligned to form a far-intermediate distance zone and an intermediate distance zone. 
     
     
         25 . The lens of  claim 24 , wherein the far-intermediate distance zone has an add power between approximately 20% and approximately 44% of the total near distance add power of the lens and the intermediate distance zone has an add power between approximately 45% and approximately 55% of the total near distance add power of the lens.