Contact lenses and methods relating thereto
A contact lens ( 101 ), the lens ( 101 ) including an optic zone ( 102 ). The optic zone ( 102 ) comprises a central region ( 105 ), the central region ( 105 ) having a centre of curvature that is on an optical axis ( 119 ). The optic zone ( 102 ) comprises a first annular region ( 103 ). The first annular region ( 103 ) has an off-axis centre of curvature that is a first distance from the optical axis ( 119 ). The first annular region ( 103 ) has a sagittal power profile that increases with increasing radial distance from the optical axis ( 119 ) with a gradient of between 1.0 D/mm and 20.0 D/mm. At a point halfway across the width of the first annular region ( 103 ), the sagittal power matches the average radial sagittal power of the central region ( 105 ).
1 . A contact lens, the lens including an optic zone comprising:
a central region, the central region having a centre of curvature that is on an optical axis; and
a first annular region, the first annular region having an off-axis centre of curvature that is a first distance from the optical axis, wherein
the first annular region has a radial sagittal power profile that increases with increasing radial distance from the optical axis, with a gradient of between about 3.0 D/mm and about 12.0 D/mm,
at a point halfway across the radial width of the first annular region, the radial sagittal power equals the average radial sagittal power of the central region, and
the radial sagittal power at an inner edge of the first annular region is between 0.5 D and 2.5 D less than the radial sagittal power at an outer edge of the central region.
2 . The contact lens according to claim 1 , wherein the radial sagittal power profile across the first annular region is linear.
3 . The contact lens according to claim 1 , wherein the radial sagittal power profile across the first annular region defines a curve having an average gradient of between about 1.0 D/mm and about 20.0 D/mm.
4 . The contact lens according to claim 1 , wherein the first annular region has a radial sagittal power profile that increases with increasing radial distance from the optical axis, with a gradient of between about 4.0 D/mm and about 12.0 D/mm.
5 . The contact lens according to claim 1 , wherein the first annular region has a radial sagittal power profile that increases with increasing radial distance from the optical axis, with a gradient of between about 3.0 D/mm and about 6.0 D/mm.
6 . A method of manufacturing the contact lens according to claim 1 , the method comprising:
forming a contact lens, wherein the lens comprises:
a central region, the central region having a centre of curvature that is on an optical axis; and
a first annular region, the first annular region having an off-axis centre of curvature that is a first distance from the optical axis, wherein
the first annular region has a radial sagittal power profile that increases with increasing radial distance from the optical axis, with a gradient of between about 3.0 D/mm and about 12.0 D/mm,
at a point halfway across the radial width of the first annular region, the radial sagittal power equals the average radial sagittal power of the central region, and
the radial sagittal power at an inner edge of the first annular region is between 0.5 D and 2.5 D less than the radial sagittal power at an outer edge of the central region.
7 . The contact lens according to claim 1 , wherein the radial sagittal power at an outer edge of the first annular region is between 0.5 D and 2.0 D greater than the radial sagittal power at an outer edge of the central region.
8 . The contact lens according to claim 1 , wherein the first annular region has a curvature providing a radial curvature add power, wherein the radial curvature add power is between +2.0 D and +10.0 D.
9 . The contact lens according to claim 1 , wherein the central region has a curvature providing the base radial curvature power, wherein the base radial curvature power is between 0.5 and −15.0 D.
10 . The contact lens according to claim 1 , wherein the first annular region extends radially outwards from a perimeter of the central region by between 0.5 and 1.5 mm.
11 . The contact lens according to claim 1 , comprising at least one additional annular region that is concentric to the first annular region, each additional annular region having an off-axis centre of curvature that is a first distance from the optical axis, wherein each additional annular region has a sagittal power profile that increases with increasing radial distance from the optical axis, with a gradient of between about 1.0 D/mm and about 20.0 D/mm.
12 . The contact lens according to claim 11 , wherein each additional annular region has a different radial sagittal power gradient to the first annular region.
13 . The contact lens according to claim 11 , wherein the radial sagittal power gradient of each additional annular region is dependent upon the radial position of the annular region.
14 . A method of reducing progression of myopia, comprising:
providing the contact lens according to claim 1 to a myopic person who is able to accommodate for varying near distances.
15 . The contact lens according to claim 11 , comprising a plurality of concentric additional annular regions, wherein the additional annular regions are separated by distance regions having the base radial curvature power.
16 . The contact lens according to claim 9 , wherein the base radial curvature power of the central region results from a curvature of an anterior surface and/or a posterior surface of the lens.
17 . The contact lens according to claim 8 , wherein the radial curvature power of the first annular region and any additional annular regions results from the curvature of an anterior surface and/or a posterior surface of the lens.
18 . The contact lens according to claim 1 , wherein the lens comprises an elastomer material, a silicone elastomer material, a hydrogel material, or a silicone hydrogel material, or mixtures thereof.
19 . The contact lens according to claim 1 , wherein the lens is a molded contact lens.
20 . A contact lens, the lens including an optic zone comprising:
a central region, the central region having a centre of curvature that is on an optical axis;
a first annular region, the first annular region having an off-axis centre of curvature that is a first distance from the optical axis, and the first annular region has a radial sagittal power profile that increases with increasing radial distance from the optical axis, with a gradient of between about 1.0 D/mm and about 20.0 D/mm, and
at least one additional annular region that is concentric to the first annular region, each additional annular region having an off-axis centre of curvature that is a first distance from the optical axis, wherein each additional annular region has a radial sagittal power profile that increases with increasing radial distance from the optical axis, with a gradient of between about 1.0 D/mm and about 20.0 D/mm, and
at a point halfway across the radial width of the first annular region, the radial sagittal power equals the average radial sagittal power of the central region.