Contact lens for keratoconus
The present invention is directed to a non-deforming contact lens for keratoconus patients comprising a central zone having a displaced central zone. In particular, the central zone is displaced from the geometric center of the lens. The shape of the central zone is egg or spoon-shaped and is rotationally asymmetrical with one semi-meridian that is shorter than a corresponding semi-meridian. An intermediate transition zone is formed integral with the periphery of the central zone, and a peripheral zone is formed integral with the periphery of the intermediate transition zone, forming a round contact lens.
1. A contact lens for keratoconus having at least three distinct zones, comprising: a central zone displaced from a two-dimensional geometric center of the contact lens the plane of the lens, wherein the central zone is rotationally asymmetrical having a meridian with a first semi-meridian shorter in radius and having a different eccentricity than a corresponding second semi-meridian; and
an intermediate transition zone formed integral with a periphery of the central zone;
a peripheral zone formed integral with a periphery of the intermediate transition zone.
2. The contact lens for keratoconus of claim 1 , wherein one semi-meridian is lower in eccentricity than the other semi-meridian.
3. The contact lens for keratoconus of claim 1 , wherein the eccentricity of the semi-meridians are substantially equivalent.
4. The contact lens for keratoconus of claim 1 , wherein the semi-meridians are unequal in eccentricity and have radii longer than a shortest semi-meridian.
5. The contact lens for keratoconus of claim 1 , wherein at a junction of the central zone and the intermediate zone, sagittal height is circumferentially equivalent.
6. The contact lens for keratoconus of claim 1 , wherein at a junction of the central zone and the intermediate zone, sagittal height has a prescribed deviation from equivalent sagittal height.
7. The contact lens for keratoconus of claim 1 , further comprising:
an anterior lens surface containing a correction for neutralizing low and higher order aberrations of a lens-eye system.
8. The contact lens for keratoconus of claim 1 , further comprising:
an anterior lens surface containing a bifocal correction.
9. The contact lens for keratoconus of claim 1 , further comprising:
an anterior lens surface containing a multifocal correction.
10. The contact lens for keratoconus of claim 1 , further comprising an encapsulated rigid lens for a bifocal or multifocal correction.
11. A kit of contact lenses for keratoconus, comprising:
at least two contact lenses, each lens having a posterior surface with a central zone displaced from a two-dimensional geometric center of the lens in the plane of the lens, wherein a series of at least three distinct zones provide a range of curvatures and diameters, and wherein an anterior surface of the lens creates lens powers respective to the posterior zone radii
wherein the central zone is rotationally asymmetrical having a meridian with a first semi-meridian shorter in radius and having a different eccentricity than a corresponding second semi-meridian.