BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to correction of eye defects, and more specifically, to a system, method and apparatus for providing binocular customized treatments for remedying presbyopia.

Description of the Related Art

Surgery on the human eye has become commonplace in recent years. Many patients pursue eye surgery as an elective procedure to treat an adverse eye condition, such as to avoid the use of contact lenses or glasses. One eye condition that can be treated surgically is presbyopia. A patient suffering from presbyopia lacks the capability of the eye lens to accommodate or bend and thus to see at far distance and at near distance. Presbyopia can be induced by age and/or pseudophakia (a condition in which a natural lens has been replaced with an intraocular lens).

Several treatment options are available for presbyopia. For example, multifocal intraocular lenses, extended depth of focus lenses, corneal inlays or other accommodating intraocular lenses can be surgically implanted in the eye of a patient suffering from presbyopia to allow the patient to focus and refocus between near and far objects. Another treatment option available to patients suffering from presbyopia is based on monovision. In this option, generally the dominant eye is targeted for distant vision and the non-dominant eye is targeted for near vision. This can be achieved by implanting the dominant eye with an intraocular lens (IOL) having a power that achieves plano refraction such that the dominant eye has no refractive error and by implanting the non-dominant eye with an IOL that has an add power between 1.0-2.0 Diopter over the dominant eye.

However, such an approach can result in sub-optimal intermediate vision if the non-dominant eye is targeted for near vision or sub-optimal near vision if the non-dominant eye is targeted for intermediate vision. Additionally, some patients may not tolerate the refractive differences in the dominant and non-dominant eye.

SUMMARY OF THE INVENTION

Multifocal intraocular lenses (IOLs) providing two or more optical powers, for example, one for near vision and one for distant vision, can be implanted in the eye of a patient suffering from presbyopia to overcome some of the disadvantages of monovision. Although multifocal IOLs can lead to improved quality of vision for many patients, some patients can experience undesirable visual effects (dysphotopsia), e.g. glare or halos. For example, if light from a distant point source is imaged onto the retina by the distant focus of a multifocal IOL, the near focus of the multifocal IOL will simultaneously superimpose a defocused image on top of the image formed by the distant focus. This defocused image may manifest itself in the form of a ring of light surrounding the in-focus image, and is referred to as a halo. Rotationally symmetric multifocal designs present symmetric halo shapes, while non-rotationally symmetric multifocal lenses present asymmetric halos. Additionally, intermediate vision may be compromised in multifocal IOLs that are configured to provide near and distant vision.

Thus, there exists a need for an ophthalmic solution that provides improved vision at all of near, far and intermediate distances while reducing dysphotopsia. One approach to provide improved vision at all of near, far and intermediate distances while reducing dysphotopsia can be a lens with an extended depth of focus. Without subscribing to any particular, a lens with an extended depth of focus can image objects with a certain distance of its focal point with acceptable sharpness on the retina. Thus, an extended depth of focus lens can produce images with acceptable sharpness for objects located at intermediate to far distances or for objects located at near to intermediate distances. Various techniques for extending the depth of focus of a lens have been proposed. For example, some approaches are based on intraocular lenses with refractive or diffractive zones with different powers.

The embodiments disclosed herein include various ophthalmic lens solutions (such as, for example, contact lenses, IOLs, phakic IOLs, corneal inlays, as well as corneal reshaping procedures such as, laser treatments, or combinations of thereof etc.) for treating ophthalmic conditions in both eyes to enhance visual acuity at near, intermediate and far distances, and therefore provide a full range of vision. In various embodiments disclosed herein, binocular extension of depth of focus is achieved by inducing rotationally symmetric aberrations (e.g. fourth and/or higher order spherical aberrations) in one eye and by inducing non-rotationally symmetric aberrations (e.g. astigmatism, coma and/or trefoil) in the other eye to enhance visual acuity at an intermediate distance. In another aspect, binocular extension of depth of focus is achieved by a rotationally symmetric diffractive lens solution in one eye and a rotationally asymmetric diffractive lens solution in the other eye. In another aspect, binocular extension of depth of focus is achieved by a rotationally symmetric refractive lens solution in one eye and a rotationally asymmetric refractive lens solution in the other eye. In another aspect, visual acuity at an intermediate distance can be enhanced by applying scaled version of natural aberrations that are present in the patient's eye, as referred in U.S. patent application Ser. No. 13/690,505 filed on Nov. 30, 2012 and entitled Lenses, Systems and Methods For Providing Custom Aberration Treatments And Monovision To Correct Presbyopia which is incorporated herein by reference, in addition to inducing rotationally symmetric and asymmetric aberrations. In an alternative embodiment, the aberration patterns (e.g. fourth and/or higher order spherical aberrations and astigmatism, coma and/or trefoil) may also be imposed on the top of monovision, achieved with either refractive or diffractive techniques or on the top of a mix and match of multifocal or extended depth of focus lenses, which may also combine symmetric and asymmetric concepts binocularly.

In various embodiments, a binocular vision simulator can be used to determine the amount and type of aberrations to be induced in each eye. The combination that provides the best through focus performance as well as the patient's comfort is chosen. An example method of implementing the concepts discussed herein includes: (i) determining with a binocular vision simulator a first amount of rotationally symmetric or non-rotationally symmetric aberration which provides visual acuity for intermediate and distant vision in a first eye; (ii) determining with the binocular vision simulator a second amount of rotationally symmetric or non-rotationally symmetric aberration which provides visual acuity for intermediate and near vision in a second eye; (iii) applying the first amount of rotationally symmetric or non-rotationally symmetric aberration in the first eye; and (iv) applying the second amount of non-rotationally symmetric or rotationally symmetric aberration in the second eye, wherein a rotationally symmetric aberration pattern is applied to the second eye if a non-rotationally symmetric aberration pattern is applied to the first eye and vice-versa. Binocular visual acuity or just visual perception at different defocus position may be tested in those conditions. The test may also be performed in the presence of rotationally symmetric and asymmetric diffractive profiles once applied using the binocular visual simulator, with a goal of determining the combination of aberrations and diffractive ophthalmic solutions which provide a continuous range of vision.

Various embodiments disclosed herein include lenses, methods and systems that can correct presbyopia by extending the depth of focus for lenses that are configured to provide distant or near vision such that improved intermediate vision is provided by binocular summation.

