Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Eye prosthesis – Intraocular lens
Reexamination Certificate
2000-09-07
2003-07-29
Willse, David H. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Eye prosthesis
Intraocular lens
C623S006370, C623S006280
Reexamination Certificate
active
06599317
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to intraocular lenses (IOLs). More particularly, the invention relates to IOLs with one or more translational 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 secured to the first portion of the optic and having a higher refractive index than the first portion and/or being positioned generally anterior of the first portion. 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.
In one embodiment, the second lens portion of the optic is comprised of an optically clear material having a higher refractive index than the first lens portion. For example, the first 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 preferably is in the range of at least 0.03 and more preferably is in the range of about 0.04 to about 0.1 or more. The second portion of the optic preferably is positioned generally anterior of the first portion. More preferably, the second portion includes an anterior surface which defines at least a portion of the anterior face of the optic.
The second lens portion may be 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 of construction for the second portion may vary significantly.
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 for relatively high refractive index and therefore effective corrective optical powers with a reduced sized 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.
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. Alternately, or in conjunction with the reshaping of the first portion, this first portion may be adapted to move axially in the mammalian eye in response to the action of the mammalian eye.
To achieve further enhanced accommodation, the optic preferably further comprises a third lens portion spaced apart from the second lens portion, secured to the first lens portion, and having a higher refractive index than the first portion, more preferably substantially the same refractive index as the second portion, and/or positioned generally posterior of the first portion. Advantageously, the second and third portions are located so that their central axes are aligned with the optical axis of the optic. Looked at from another perspective, the second portion may be considered as an anterior lens portion while the third portion may be considered a posterior lens portion. The first portion preferably is situated between the second and third portions.
The embodiment of the present IOLs with the optic including second and spaced apart third lens portions is advantageous in that the optic is still responsive to the force exerted by the eye on the optic while, at the same time, the positioning and/or refractive indexes and/or optical powers of the second and third portions provide for obtaining enhanced accommodation with such an optic. The second lens portion, for example, the anterior lens portion, may have a higher, preferably positive, optical power than the third lens portion, for example, the posterior lens portion. In other words, the second lens portion can have a positive optical power relative to the baseline optical power, which is the optical power for distance vision correction, and the third lens portion can have a negative optical power relative to the baseline optical power. The use of lens portions with positive and negative optical powers, for example, highly positive and highly negative optical powers, extends the total accommodative dioptic change beyond that of the movement of a single lens design. Such positive
egative lens portions including a relatively easily deformable first portion provide a larger dioptic power change relative to a single lens design based on the same amount of movement of the lens in the eye. Thus, increased or enhanced amounts of accommodation are provided using the present optics including positive and negative lens portions.
As noted previously, the second and third lens portions of the optic may have substantially the same refractive index. More preferably, the second and third portions of the optic are made of substantially the same material, that is material having substantially the same chemical makeup. The refractive index of each of the second portion and the third portion of the optic preferably is at least about 1.42.
The reshaping or deformation of the first lens portion can cause an axial movement of the first portion which imparts an axial movement of the second lens portion, or the second and/or third portions of
Ghazizadeh Massoud
Liao Charles X.
Weinschenk, III Joseph I.
Advanced Medical Optics, Inc.
Gluck Peter Jon
Stout, Uxa Buyan & Mullins, LLP
Uxa Frank
Willse David H.
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