Enhanced toric 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 an enhanced toric lens which redirects and/or focuses light incident on the eye at oblique angles onto a peripheral retinal location. The intraocular 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 intraocular lens can be configured to improve or reduce peripheral errors at the location on the peripheral retina. One or more surfaces of the intraocular 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. A method of selecting an intraocular lens (IOL) configured to be implanted in a patient's eye, the method comprising:
obtaining at least one characteristic of the patient's eye using a diagnostic instrument; and
selecting an IOL having an optical power that reduces optical errors in an image produced at a peripheral retinal location of the patient's eye disposed at a distance from the fovea, wherein the IOL is configured to produce an image by focusing light incident on the patient's eye at an oblique angle with respect to an optical axis intersecting the patient's eye at the peripheral retinal location, wherein a modulation transfer function (MTF) of the IOL at one or more spatial frequencies for light incident on the IOL at the oblique angle having a value between 1 and 25 degrees with respect to the optical axis at the peripheral retinal location is greater than a modulation transfer function (MTF) of the IOL at one or more spatial frequencies for light incident on the optic at an angle less than 1 degree with respect to the optical axis at the fovea,
wherein the optical power of the IOL is based on the obtained characteristic, and
wherein a first surface of the IOL is a Zernike surface.
2. The method of claim 1 , wherein a second surface of the IOL is a spherical surface.
3. The method of claim 1 , wherein the obtained characteristic includes axial length along the optical axis of the patient's eye and corneal power.
4. The method of claim 3 , wherein the optical power is obtained from an estimate of an axial length along an axis which deviates from the optical axis and intersects the retina at the peripheral retinal location, the estimate based on the axial length along the optical axis of the patient's eye and corneal power.
5. The method of claim 1 , wherein the obtained characteristic is selected from the group consisting of axial length along the optical axis of the patient's eye, corneal power based at least in part on measurements of topography of the cornea, an axial length along an axis which deviates from the optical axis and intersects the retina at the peripheral retinal location, a shape of the retina, and a measurement of optical errors at the peripheral retinal location.
6. The method of claim 1 , wherein at least one of the surfaces of the IOL includes a redirecting element.
7. The method of claim 6 , wherein the redirecting element comprises a diffractive feature.
8. The method of claim 6 , wherein the redirecting element comprises a prismatic feature.
9. The method of claim 1 , wherein the IOL is configured to provide at least 0.5 Diopter of astigmatic correction at the peripheral retinal location.
10. The method of claim 1 , wherein the IOL is configured to provide at least 0.1 μm of coma correction at the peripheral retinal location for a 6 mm pupil.
11. The method of claim 1 , wherein the image has reduced coma.
12. The method of claim 1 , wherein the image has reduced astigmatism.
13. The method of claim 1 , wherein the oblique angle is between about 1 degree and about 25 degrees.
14. The method of claim 1 , wherein the IOL has a modulation transfer function (MTF) of at least 0.3 for a spatial frequency of 30 cycles/mm for both tangential and sagittal foci at the peripheral retinal location.