Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Eye prosthesis – Intraocular lens
Reexamination Certificate
2000-09-07
2003-11-11
Willse, David H. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Eye prosthesis
Intraocular lens
C623S006130, C623S006220, C623S006270
Reexamination Certificate
active
06645246
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to intraocular lenses (IOLs). More particularly, the invention relates to IOLs including surrounded lens zones which are adapted to provide accommodation in the eye.
The human eye includes an anterior chamber between the cornea and iris, a posterior chamber, defined by a capsular bag, containing a crystalline lens, a ciliary muscle, a vitreous chamber behind the lens containing the vitreous humor, and a retina at the rear of this chamber. The human eye has a natural accommodation ability. The contraction and relaxation of the ciliary muscle provides the eye with near and distant vision, respectively. This ciliary muscle action shapes the natural crystalline lens to the appropriate optical configuration for focusing light rays entering the eye on the retina.
After the natural crystalline lens is removed, for example, because of cataract or other condition, a conventional, monofocal IOL can be placed in the posterior chamber. Such a conventional IOL has very limited, if any, accommodating ability. However, the wearer of such an IOL continues to require the ability to view both near and far (distant) objects. Corrective spectacles may be employed as a useful solution. Recently, multifocal IOLs without accommodating movement have been used to provide near/far vision correction.
Attempts have been made to provide IOLs with accommodating movement along the optical axis of the eye as an alternative to shape changing. Examples of such attempts are set forth in Levy U.S. Pat. No. 4,409,691 and several patents to Cumming, including U.S. Pat. Nos. 5,674,282 and 5,496,366. The disclosure of each of these patents is incorporated herein by reference. One problem that exists with such IOLs is that they often cannot move sufficiently to obtain the desired accommodation.
It would be advantageous to provide IOLs adapted for accommodating movement which can achieve an increased amount of accommodation.
SUMMARY OF THE INVENTION
New accommodating IOLs have been discovered. The present accommodating IOLs take advantage of employing an optic made of two different materials to enhance the accommodation achievable in the eye in response to normal accommodative stimuli. Thus, the present lenses provide for controlled vision correction or focusing for both near objects and far or distant objects. Further, a greater overall range of accommodation is often achieved. The present IOLs are relatively straightforward in construction and to manufacture or produce, can be implanted or inserted into the eye using systems and procedures which are well known in the art and function effectively with little or no additional treatments or medications being required.
In one broad aspect of the present invention, intraocular lenses (IOLs) are provided and comprise an optic adapted to focus light toward a retina of a mammalian eye and, in cooperation with the mammalian eye, to provide accommodation. The optic includes a first lens portion adapted to move in response to the action of the mammalian eye; and a second lens portion surrounded by the first lens portion of the optic, and having a higher refractive index or index of refraction than the first portion and/or being less deformable than the first portion in response to forces exerted by the mammalian eye.
The first lens portion is comprised of an optically clear material that is easily reshaped and/or is axially movable when exposed to force exerted by the mammalian eye. The second lens portion of the optic is comprised of an optically clear material having a higher refractive index than the first portion and/or being less deformable than the mammalian eye. For example, the first lens portion may have a refractive index of about 1.37 or less, while the second portion preferably has a refractive index of at least about 1.42. The difference in refractive index between the first and second portions may be in the range of at least about 0.03 and may be in the range of about 0.04 to about 0.1 or more. However, the second portion of the present optic may have a higher, lower or the same refractive index relative to the refractive index of the first portion. For example, both first and second portions of the present optics may have refractive indexes of about 1.37 or less. In one useful embodiment, both the first and second lens portions have refractive indexes of at least about 1.40 and/or at least about 1.42.
The second lens portion may be deformable or reshapable by the force exerted on the optic by the eye or may be substantially rigid in response to such force. As a result of this, potential materials for the second lens portion may vary significantly.
In one embodiment, the present lenses very effectively provide for both enhanced movement, for example reshaping and/or axial movement because of the substantially compliant or deformable first lens portion, while, at the same time, providing effective corrective optical powers with a reduced sized, e.g., thickness, lens because of the higher refractive index second lens portion. This combination of enhanced movement and high refractive index provides a substantial benefit in achieving accommodation in the mammalian eye.
Advantageously, the second lens portion of the optic is less deformable in the eye than is the first lens portion. Having a second portion with reduced deformability adds stability to the optic in the eye. The movement, for example, reshaping and/or axial movement, of the optic in the eye is achieved with reduced risk that such movement can misshape or otherwise distort the optic which can detrimentally affect the vision of the wearer of the IOL. In other words, the relatively rigid second lens portion of the optic may provide for a more controlled or reproducible movement of the optic in the eye relative to a similar optic without the second portion.
The second lens portion of the optic may be positioned at any suitable location in the optic. The second portion advantageously is substantially symmetrical about the optical axis of the optic. The second portion preferably is substantially centrally located within the first portion. The second lens portion is often secured to the first lens portion.
In one very useful embodiment, the first lens portion of the optic is adapted to be reshaped in response to the action of the mammalian eye. In particular, the first lens portion includes an anterior surface and is adapted to be reshaped in response to the action of the mammalian eye. This reshaping preferably is effective to change the curvature of the first portion, for example, the anterior surface of the first portion. Such change in curvature alters the optical power of the optic and is effective in providing at least a portion of the desired accommodation. Alternately, and preferably in conjunction with the reshaping of the first lens portion, this first portion may be adapted to move axially in the mammalian eye in response to the action of the mammalian eye to provide additional accommodation.
Advantageously, the first and second lens portions of the optic are located so that their central axes are aligned with the optical axis of the optic. Looked at from another perspective, the second lens portion may be considered as a core or center of the optic while the first portion may be considered an outer layer or covering of the optic.
The reshaping or deformation of the first portion can cause an axial movement of the first portion which imparts an axial movement of the second portion of the optic. Axial movement of the portion of the optic with the greater dioptic power, most likely the high refractive index portion, e.g., the second lens portion, of the optic, has a relatively large effect on the accommodative power of the optic. Thus, axial movement of the second portion of the optic can be one feature of the present invention effective in providing accommodation. Of course, reshaping of the first portion in and of itself provides accommodative power, for example, by changing the curvature of the anterior surface of the first portion. The over
Ghazizadeh Massoud
Liao Charles X.
Weinschenk, III Joseph I.
Advanced Medical Optics, Inc.
Blanco Javier G.
Gluck Peter J.
Willse David H.
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