Systems, methods and devices for controlling the progression of myopia
An ophthalmic lens system for reducing the risk of progression of a myopic eye by selectively maintaining, inducing or creating asymmetry of the peripheral retinal profile for the eye. A method for reducing the risk of progression of myopia comprising determining the magnitude of asymmetry of the on-axis/off-axis refractive error profile or eye length profile of the eye and providing an ophthalmic lens system that corrects for and provides acceptable on-axis vision and simultaneously controls the position of the off-axis refractive error profile or eye length profile such that resultant profile of the eye is asymmetric.
1. An ophthalmic system for a myopic eye, the system comprising:
a central optical zone with a first focal length;
a temporal optical zone with a second focal length different to the first focal length and configured to focus images at the nasal peripheral retina of the eye, and a nasal optical zone with a third focal length different from the first focal length and configured to focus images at the temporal peripheral retina of the eye,
wherein the first focal length is selected to provide acceptable vision for distance and the second and third focal lengths are selected such that the second focal length is shorter than the first and third focal lengths so as to induce asymmetry; and
wherein the second focal power profile is relatively more positive than at least the third surface power profiles by about 0.75 D.
2. The ophthalmic system of claim 1 , wherein the temporal optical zone and the nasal optical zone provide variable focal lengths across their respective optical zones and wherein the average focal length within the temporal optical zone is the second focal length and the average focal length of the nasal optical zone is the third focal length.
3. The ophthalmic system of claim 1 , wherein the ophthalmic system is a contact lens or a spectacle lens.
4. The ophthalmic system of claim 3 , wherein the ophthalmic system comprises a lens power profile and the first, second and third focal lengths are determined by the lens power profile.
5. The ophthalmic system of claim 1 , wherein the ophthalmic system is an orthokeratology lens or a corneal implant or an eye of a patient as a result of a refractive surgery.
6. The ophthalmic system of claim 1 , wherein the first, second and third focal lengths are determined by the effect of the ophthalmic system on the corneal curvature or corneal power or both.
7. The ophthalmic system of claim 1 , wherein the central optical zone, temporal optical zone and the nasal optical zone are substantially unequal in surface area.
8. The ophthalmic system of claim 1 , wherein the ophthalmic system is selected from one or more of a retinal implant, a scleral implant, a scleral buckle or a retinal prosthesis.
9. An ophthalmic lens for a myopic eye, the lens comprising:
a horizontal axis that includes a center point of the lens and extends across the lens from the most nasal side of the lens to the most temporal side of the lens when the lens is in an as worn position,
a central optical zone with a first power profile for correcting the refractive error at the fovea of the eye, the central optical zone comprising the center point of the lens, a temporal optical zone with a second power profile, different than the first power profile, to focus images substantially close to or on the nasal peripheral retina, the temporal optical zone located temporally when in a worn position and comprising a region along the horizontal axis, and
a nasal optical zone with a third power profile, different from the first power profile, to focus images substantially close to or on the temporal peripheral retina, the nasal optical zone located nasally when in a worn position and comprising a region along the horizontal axis,
wherein the second and third power profiles are selected such that the second power profile is relatively more positive than the first and third power profile so as to induce asymmetry; and
wherein the second focal power profile is relatively more positive than at least the third surface power profiles by about 0.75 D.
10. The lens of claim 9 , wherein the ophthalmic lens is a spectacle lens.
11. The lens of claim 9 , wherein the ophthalmic lens comprises an orthokeratology lens and wherein the first to third power profiles are effected as a reshaping of the cornea of the eye.
12. The lens of claim 9 , wherein the ophthalmic lens is a contact lens and further comprises a lens stabilizing mechanism for orienting the lens on the eye.
13. The lens of claim 12 , wherein the central optic zone is located between the nasal and the temporal optic zones, the central optic zone being asymmetrical about a vertical meridian through the lens, wherein the vertical and horizontal meridians refer to an orientation of the lens caused by the stabilizing mechanism.
14. The lens of claim 13 wherein the central optic zone is not piano and includes a refractive power for correcting defocus.