Contact lens with meridional sagittal variation and methods for making and using the same
The present invention is directed toward the design of lenses to incorporate elevation features in at least one annular zone on the posterior surface of the lens that engage the elevation differences of the eye while allowing the central zone of the lens to have conventional spherical, aspheric, multifocal or toric geometry. In various embodiments, lenses according to the present invention are rotationally stable, free of flexure and well centered over the pupil.
1. A contact lens comprising:
a central zone, an annular zone, and an edge reconciliation zone,
wherein the annular zone comprises:
a first point located on the posterior surface of the lens at a chord diameter along a first meridian having a first sagittal depth, and
a second point located on the posterior surface of the lens at said chord diameter along a second meridian having a second sagittal depth, wherein said second sagittal depth differs from said first sagittal depth; and
wherein a perimeter of the lens lies within a single plane and is circular.
2. A contact lens in accordance with claim 1 , wherein the central zone is independently configured to have one of a spherical, aspheric, multifocal or toric geometry.
3. A contact lens in accordance with claim 2 , wherein the posterior surface of the central zone is at least partially configured to topographically engage the cornea of an eye.
4. A contact lens in accordance with claim 2 , wherein the posterior surface of the central zone is not configured to topographically engage the cornea of an eye.
5. A contact lens in accordance with claim 1 , wherein a plurality of contact lens posterior surface meridians converge to yield a spatially symmetric edge.
6. A contact lens in accordance with claim 1 , wherein a plurality of contact lens anterior surface meridians are independent of the plurality of contact lens posterior meridians.
7. A contact lens in accordance with claim 1 , wherein the lens has at least one annular zone that has a posterior meridional transition profile defined by a third order polynomial.
8. A contact lens in accordance with claim 1 , wherein the lens has at least one annular zone that has a posterior meridional transition profile defined by a conic constant.
9. A contact lens in accordance with claim 1 , wherein the lens has at least one annular zone having a radius of curvature shorter than that of the central zone.
10. A contact lens in accordance with claim 1 , wherein the lens has at least one annular zone that is uncurved and defined by an angle.
11. A contact lens, comprised of at least one annular zone having a sagittal elevation difference between at least two points located the same radial distance from the center axis of the lens, wherein a perimeter of the lens lies within a single plane and is circular.
12. A contact lens in accordance with claim 11 , wherein the anterior surface of the lens is spatially symmetric and without aberration.
13. A contact lens in accordance with claim 11 , further comprising at least twelve semi-meridians, each of which has an independently configured radial transition.
14. A contact lens comprising:
a central zone, an annular zone, and an edge reconciliation zone,
wherein the annular zone comprises:
a first semi-meridian and a second semi-meridian, wherein a first radial transition of the first semi-meridian differs from a second radial transition of the second semi-meridian; and
wherein a perimeter of the lens lies within a single plane and is circular.
15. A contact lens in accordance with claim 14 , wherein the rotational transition from said first semi-meridian to said second semi meridian is defined by a third order polynomial, a conic constant, or is uncurved and defined by an angle.
16. A contact lens comprising:
a central zone, a first annular zone, a second annular zone, and an edge reconciliation zone,
wherein the lens is a soft contact lens;
wherein the posterior surface of the central zone is not configured to spatially match the topography of the cornea;
wherein the first annular zone is configured to engage at least one topographical aberration on the surface of at least one of the cornea and sclera;
wherein the second annular zone is configured for corneal reshaping; and
wherein a perimeter of the lens lies within a single plane and is circular and is configured to rest at or near the limbal junction.
17. A method of making a lens comprising:
obtaining at least one of corneal and scleral elevation data
selecting the radius of curvature of a central zone based upon the obtained elevation data;
applying spline mathematics or other curve fitting methods to the obtained elevation data to define a lens annular zone comprised of a plurality of posterior lens radial meridional transitions and at least one rotational transition between said plurality of posterior lens radial meridional transitions; and
cutting a lens from a pre-formed lens button or blank using a lathe, wherein the lens comprises said lens central zone and said lens annular zone, and wherein a perimeter of the lens lies within a single plane and is circular.
18. A kit comprising a plurality of lenses for use in fitting a plurality of eyes having geometric diversity over at least one of their respective corneal and scleral regions,
wherein each of said plurality of lenses is comprised of at least one annular zone having a sagittal elevation difference between at least two points located the same radial distance from the center axis of the lens,
wherein a perimeter of the lens lies within a single plane and is circular, and
wherein each of said plurality of lenses comprises at least one of a different posterior surface profile and central zone geometry to allow fitting said plurality of eyes.
19. A kit in accordance with claim 18 , wherein each of said plurality of lenses has an outer diameter of from about 7 mm to about 24 mm.