Ophthalmic lens with optimal power profile

Abstract

An ophthalmic lens includes an optical zone having a center and a spaced-apart periphery. The optical zone has a first corrective power range in a first region and a second corrective power range in an annular region surrounding the first optical zone. The second corrective power is corrective of spherical aberration of an eye. The optical zone has a power profile that gradually changes from the first corrective power to the second corrective power. A central progressive zone that provides intermediate vision correction may be applied to a central region of the lens. The progressive zone has a diameter that is less than or equal to the diameter of an aperture of a pupil when subjected to bright light.

1 . An ophthalmic lens, comprising an optical zone having a center and a spaced-apart periphery, 
 the optical zone having a first corrective power range in a first region and a second corrective power range in an annular region that surrounds the first region    the lower limit of the first corrective power range being equal approximately to the manifest corrective refractive power for an eye;    the upper limit of the second corrective power range being equal approximately to the manifest corrective refractive power for the eye;    the second corrective power range having negative spherical aberration varying with diameter and being less than the manifest corrective refractive power for an eye at the periphery of the optical zone,    the optical zone having a power profile such that the optical power of the optical zone decreases from the center to the periphery of the optical zone.    
   
   
       2 . The ophthalmic lens of  claim 1 , wherein the first region is coaxial with the center.  
   
   
       3 . The ophthalmic lens of  claim 1 , wherein the annular region is coaxial with the center.  
   
   
       4 . The ophthalmic lens of  claim 1 , wherein the surface of the first region is described by a spline function and the surface of the annular region is described by a polynomial or conic function.  
   
   
       5 . The ophthalmic lens of  claim 1 , wherein the upper limit of the first corrective power range is 2 to 6 diopters greater than the manifest corrective refractive power for the eye.  
   
   
       6 . The ophthalmic lens of  claim 1 , wherein corrective power at a 6 mm diameter is 0.5 to 2 diopters less than the manifest corrective refractive power for an eye.  
   
   
       7 . The ophthalmic lens of  claim 1 , wherein the optical zone has an axis and wherein the axis of the optical zone is aligned to a line-of-sight of an eye.  
   
   
       8 . The ophthalmic lens of  claim 2 , wherein the first region is a circular zone having a first diameter no greater than a diameter of a pupil exposed to bright light.  
   
   
       9 . The ophthalmic lens of  claim 8 , wherein the first diameter is less than 2.0 mm.  
   
   
       10 . The ophthalmic lens of  claim 9 , wherein the upper limit of the first corrective power range is 2 to 6 diopters greater than the manifest corrective refractive power for the eye, and wherein corrective power at a 6 mm diameter is 0.5 to 2 diopters less than the manifest corrective refractive power for an eye.  
   
   
       11 . A method of designing an ophthalmic lens having a center and a spaced-apart periphery that is coaxial with the optical axis of the ophthalmic lens, comprising the steps of: 
 (a) generating a description of a power profile of the lens so that the lens has a first corrective power range in a first central circular region with a first diameter and so that the lens has a second corrective power range in an annular region extending outwardly from the first diameter to a second diameter being the outer diameter of the annular region, the second corrective power range having negative spherical aberration varying with diameter and being less than the manifest corrective refractive power for an eye;    (b) generating in a recursive manner a spline function to define the surface of the first central circular region; and    (c) generating a polynomial or conic function that describes a surface that is tangent to the surface of the first optical zone.    wherein the surface of the first central circular region is tangent to the surface of the annular region, and wherein the surfaces described by the spline function and the polynomial or conic function provide the power profile of the lens.    
   
   
       12 . The method of  claim 11 , wherein the first diameter is no greater than a diameter of a pupil exposed to bright light.  
   
   
       13 . A method of manufacturing a lens, comprising the steps of: 
 (a) determining a power profile of a lens having a first corrective power range for intermediate vision correction in a central optical zone having a first diameter and a second corrective power range in an annular optical zone extending outwardly from the central optical zone to a second diameter, the second corrective power range capable of correcting spherical aberration of an eye;    (b) generating a model of a lens having the power profile; and    (c) fabricating a tool, mold or lens on a 3-axis lathe to create surfaces and optical surface corresponding to the prescribed optical power profile    
   
   
       14 . The method of  claim 13 , wherein the first corrective power range comprises a corrective power used for “computer vision.” 
   
   
       15 . The method of  claim 13 , wherein the central optical zone has a diameter that is less than 2 mm.  
   
   
       16 . The method of  claim 13 , wherein the annular optical zone comprises a surface that is described by a polynomial or conic function.  
   
   
       17 . The method of  claim 13 , wherein the central optical zone comprises a surface that is described by a spline function.  
   
   
       18 . The method of  claim 17 , wherein the upper limit of the first corrective power range is 2 to 6 diopters greater than the manifest corrective refractive power for the eye.  
   
   
       19 . The method of  claim 17 , wherein corrective power at a 6 mm diameter is 0.5 to 2 diopters less than the manifest corrective refractive power for an eye.