Contact lenses

Abstract

A set of contact lenses having peripheral zones with optical power parameters determined in relation to the optical powers of the central portions of the lenses. In a specific embodiment, an optical parameter assigned to a given peripheral zone of a lens from the set represents a difference between an optical power of the lens in such peripheral zone and an optical power of the lens in the central portion. A method for determining optical parameters of such set of lenses and an apparatus implementing such determination based on imaging data acquired as a result of imaging an eye and generation of a representation of the lenses at least in part of such imaging data.

What is claimed is: 
     
         1 . A set of contact lenses, each lens in the set comprising:
 a differentiable posterior surface including a posterior optical zone (POZ) having a POZ diameter and a normal to a surface of the POZ passing through a center of the POZ;   at least five peripheral zones (PZs) each of which encircles said POZ and has corresponding inner and outer perimeters, wherein immediately adjacent peripheral PZs from said at least five annular PZs share a perimeter, the at least five PZs having respectively corresponding optical power parameters that define slopes of the posterior surface with respect to the normal; and   a POZ optical power of the lens corresponding to the POZ and common among the lenses in the set.   
     
     
         2 . A set of lenses according to  claim 1 , each lens of the set further comprising
 a first optical power parameter corresponding to an inner PZ from the at least five annular PZs, the inner PZ adjoining the POZ; and   a second optical power parameter corresponding to an outer PZ from the at least five annular PZs, the outer PZ having the largest outer perimeter among the at least five PZ,   the first and second optical power parameters having opposite signs and being common among the lenses of the set   wherein each of the first and second optical power parameters represents a difference between an optical power of the lens in a respectively corresponding PZ and said POZ optical power of the lens.   
     
     
         3 . A set of contact lenses according to  claim 1 , wherein the at least five annular peripheral PZs have equal widths. 
     
     
         4 . A set of contact lenses according to  claim 1 , comprising first and second lenses,
 wherein each of the first and second lenses has a corresponding POZ optical power equal to about −3.0 diopters; a corresponding POZ diameter equal to about 6.5 mm, a diameter of about 9.0 mm; a base curve parameter of about 7.85; an eccentricity parameter of about 0.2; a center thickness of about 0.14 mm; an edge thickness of about 0.11 mm; first, second, third, fourth, and fifth peripheral PZs having respective optical parameters of about −0.5, 0.5, 1.25, and 2.50;   wherein the first lens is adapted to have the POZ optical power of the first lens vary from about −3.0 diopters at a radius of about 3.1 mm from a center of the first lens to about 0.25 diopters at an edge of the POZ of the first lens; and   wherein the second lens is adapted to have the POZ optical power of the second lens vary from about −3.0 diopter at a radius of about 2.9 mm from a center of the second lens to about 0.25 diopters at an edge of the POZ of the second lens.   
     
     
         5 . A set of contact lenses according to  claim 1 , each lens in the set further comprising intermediate optical power parameters respectively corresponding to intermediate PZs from the at least five annular PZs, the intermediate PZs disposed between the first and second PZs and having progressively larger outer perimeters, wherein each of the intermediate power parameters represents a difference between an optical power of the lens in a respectively corresponding intermediate PZ and said POZ optical power of the lens. 
     
     
         6 . A set of contact lenses according to  claim 5 , wherein the intermediate optical power parameters form a set of ascending values. 
     
     
         7 . A set of contact lenses according to  claim 1 , each lens in the set further comprising at least one of a lens diameter and a diameter of the POZ, the at least one of a lens diameter and a diameter of the POZ being common among the lenses in the set. 
     
     
         8 . A method for using a contact lens from the set of contact lenses according to  claim 1 , the method comprising receiving said contact lens and fitting said contact lens to an eye. 
     
     
         9 . A method for determining parameters of a set of contact lenses, the method comprising:
 receiving imaging data representing an eye;   determining an optical parameter of a central portion of a lens of the set to correct a deviation of an optical characteristic of the eye from a corresponding optical characteristic of a normal eye;   defining an optical power parameter corresponding to an annular PZ of the lens that encircles the central portion of the lens, said optical parameter representing a difference between an optical power of the lens in said PZ and an optical power of the lens in the central portion.   
     
     
         10 . A method according to  claim 9 , wherein said defining includes defining an optical power parameter representing an inclination of a posterior surface of the lens across the PZs with respect to a posterior surface of the lens in its central portion. 
     
     
         11 . A method according to  claim 9 , wherein said defining includes defining an optical power parameter based on an empirically acquired data base. 
     
     
         12 . A method according to  claim 9 , wherein said defining includes defining at least three optical power parameters respectively corresponding to a first, second, and third annular PZs each of which encircles said central portion and has corresponding inner and outer perimeters and width,
 wherein immediately adjacent annular PZs from said at least three annular PZs share a perimeter.   
     
     
         13 . A method according to  claim 9 , further comprising calculating a curvature of a posterior surface of said lens based on said optical power parameter. 
     
     
         14 . A method for determining a curvature of a posterior surface of a contact lens, the method comprising:
 receiving input data representing said contact lens having a substantially circular central portion and an annular peripheral zone (PZ) encircling said central portion, said input data including an optical power parameter corresponding to the PZ; and   calculating a geometrical parameter associated with the curvature of the posterior surface of said contact lens based on said input data.