Piggyback intraocular lens that improves overall vision where there is a local loss of retinal function
Systems and methods are provided for improving overall vision in patients suffering from a loss of vision in a portion of the retina (e.g., loss of central vision) by providing a piggyback lens which in combination with the cornea and an existing lens in the patient's eye redirects and/or focuses light incident on the eye at oblique angles onto a peripheral retinal location. The piggyback lens can include a redirection element (e.g., a prism, a diffractive element, or an optical component with a decentered GRIN profile) configured to direct incident light along a deflected optical axis and to focus an image at a location on the peripheral retina. Optical properties of the piggyback lens can be configured to improve or reduce peripheral errors at the location on the peripheral retina. One or more surfaces of the piggyback lens can be a toric surface, a higher order aspheric surface, an aspheric Zernike surface or a Biconic Zernike surface to reduce optical errors in an image produced at a peripheral retinal location by light incident at oblique angles.
1. An ophthalmic lens configured to improve vision for a patient's eye, the lens comprising:
an optic with a first surface and a second surface opposite the first surface, the optic having an optical axis that intersects the first and the second surface, wherein the optic when disposed in an eye of a patient is configured to reduce optical errors together with a cornea and an existing lens in the eye of the patient due to at least one of astigmatism or coma for light incident at an oblique angle with respect to an optical axis of the eye of the patient and focused at a peripheral retinal location disposed at a distance from the fovea and at an eccentricity of about 1 degree to about 25 degrees with respect to the fovea in a horizontal or a vertical plane,
wherein the first surface or the second surface of the optic is configured as a higher order aspheric surface, an aspheric Zernike surface or a Biconic Zernike surface described by at least one of (i) aspheric coefficients having an order greater than or equal to 8, or (ii) at least six Zernike coefficients,
wherein a thickness of the optic along the optical axis of the optic is less than 1.0 mm,
wherein a refractive power provided by the optic is between −5.0 Diopter and +5.0 Diopter, and
wherein an astigmatic power provided by the optic is between 0.5 Diopter and 6.0 Diopter.
2. The lens of claim 1 , wherein the oblique angle is between about 1 degree and about 25 degrees.
3. The lens of claim 1 , wherein a thickness of the optic varies about a periphery of the optic.
4. The lens of claim 1 , wherein the optic is configured such that when disposed in the eye of the patient the optic together with the cornea and the existing lens has a modulation transfer function (MTF) of at least 0.3 for a spatial frequency of 30 cycles/mm for both the tangential and the sagittal foci at the peripheral retinal location.
5. The lens of claim 1 , wherein the optic is configured such that when disposed in the eye of the patient the optic together with the cornea and the existing lens has a modulation transfer function (MTF) of at least 0.5 for a spatial frequency of 100 cycles/mm for both the tangential and the sagittal foci at the fovea.
6. The lens of claim 1 , wherein the thickness of the optic along the optical axis of the optic is between about 0.1 mm and about 0.9 mm.
7. The lens of claim 6 , wherein the optic is symmetric about the optical axis of the optic.
8. The lens of claim 1 , wherein the optic is configured to be implanted between the iris and the existing lens.
9. The lens of claim 1 , wherein the existing lens is configured to provide foveal vision.
10. The lens of claim 1 , wherein the first and the second surface are convex.
11. The lens of claim 1 , wherein the optic includes diffractive features.
12. The lens of claim 1 , wherein the existing lens is a natural lens.
13. The lens of claim 1 , wherein the existing lens is an intraocular lens.