WO1992003989A1

WO1992003989A1 - Variable power intraocular lens with astigmatism correction

Info

Publication number: WO1992003989A1
Application number: PCT/US1991/006414
Authority: WO
Inventors: Robert G. Wiley; William G. Martin
Original assignee: Wiley Robert G; Martin William G
Priority date: 1990-09-04
Filing date: 1991-09-03
Publication date: 1992-03-19
Also published as: CA2067247A1; JPH05502185A; EP0500922A1

Abstract

An intraocular lens has a flexible lens body (34) formed from optically clear material surrounded by an outer ring (36) which is sensitive to an external force. Utilizing the external force, the shape of the outer ring (36) can be changed to elongate the lens body (34) along an axis for correcting astigmatism, or to change the lens power by altering the lens's spherical shape or curvature. Attached to one of the lens body (34) and the ring (36) are actuator bodies (38) of ferromagnetic material. An adjustable focus lens apparatus includes a transparent lens body (34) and a rigid outer ring (40) extending about the lens body periphery and micromotor devices (38) spaced equally about and coupled between the ring (40) and the periphery (34). Each micromotor device (38) is responsive to an externally generated control signal for selectively changing the circumference and/or axial position of an association portion of the periphery to adjust the lens for power and astigmatism correction.

Description

TITLE

VARIABLE POWER INTRAOCULAR LENS

WITH ASTIGMATISM CORRECTION

BACKGROUND OF THE INVENTION The present invention relates generally to an intraocular lens and, in particular, to an apparatus for varying the power of and providing astigmatism correction in an intraocular lens.

The lens of the human eye is located centrally behind the pupil and is protected by the cornea. In the normal eye, the lens is clear and is substantially symmetrical, with opposed convex surfaces defining generally spherical sections. The lens and the cornea cooperate to focus light on the retina. The retina in turn cooperates with the nerves and the brain, so that light impinging on the retina is perceived as an image.

The light refraction which takes place in the cornea and the lens translates into an optical correction of about 60 diopters, with the cornea accounting for about 40 diopters and the lens accounting for about 20 diopters.

Other refracting structures also are present in the eye, but are disregarded to simply the subject explanation.

A cataract is a condition where the normally clear lens of the eye becomes progressively opaque. This opacification typically occurs over an extended period of time, and the amount of light which passes through the lens decreases with increasing degrees of opacity. As the ability of the cataract lens to transmit light decreases, the ability of the eye to perceive images also decreases. Blindness ultimately can result. Since there are no known methods for eliminating the opacity of a cataract lens, it generally is necessary to surgically remove the opaque lens to permit the unobstructed passage of light through the pupil to the retina. The cataract lens is removed through a generally horizontal incision made at the superior part of the juncture where the cornea and sclera meet.

Once the lens has been surgically removed, light can be readily transmitted through the pupil and toward the retina. As noted above, the lens of the eye performs a significant light focusing function. Consequently, with the lens removed, the optical system of the eye is left about 20 diopters "short", and light is no longer properly focused on the retina. Eyeglasses, contact lenses and intraocular lenses are the three types of optical aids that commonly may be employed after cataract surgery to refocus the light on the retina.

Eyeglasses include lenses which are spaced from the cornea of the eye. The air space between the lens and the cornea causes an image magnification of more than 7%. Unfortunately, the brain cannot assimilate this magnification in one eye, and as a result an object appears double. This is a particular problem if the individual had only one cataract eye. Eyeglasses also substantially limit peripheral vision.

Contact lenses rest directly on the cornea of the eye, thus eliminating the air space. As a result, there is a much smaller image magnification with contact lenses than there is with eyeglasses, and the brain typically can fuse the images perceived by an eye with a contact lens and one without. Contact lenses, however, are less thfn perfect. For example, contact lenses are quite fragile and can be easily displaced from their proper position on the cornea. Additionally, the lenses must be periodically replaced because of protein build-up on the surface of the lens which can cause conjunctivitis. Furthermore, many of the elderly people who require cataract operations do not have the required hand coordination to properly remove or insert the lens.

Intraocular lenses first because available as optical aids to replace removed cataract lenses in about 1955. These lenses are placed in the eye, and thus closely simulate the optics of the natural lens which they are replacing. Unlike eyeglasses, there is virtually no image distortion with a properly made and placed intraocular lens. Also, unlike contact lenses, there is no protein build-up on the intraocular lenses and the lenses require no care by the patient.

To place the lens in the eye, the surgeon ordinarily makes an incision or opening in the sclera and cornea to allow the insertion of the lens into the eye. Normally, the stabilizing loops of the attachment members of the lens are flexible and can be bent, if necessary, to pass through the opening. Accordingly, the minimum length of opening which must be made and is ordinarily determined by the diameter of the substantially rigid lens body, or optic, usually having a circular periphery. It is, of course, desirable to make the opening into the eye as small as possible to minimize the risk of damage to the eye. In the past few years, some lenses have been made of flexible material like silicone that can be folded so as to go into the eye through a smaller opening.

The current practice in the implantation of intraocular lenses is to replace a normal crystalline human lens of the eye removed at the time of surgery, such as in cataract surgery, with an intraocular lens such as an anterior chamber lens or posterior chamber lens formed of appropriate biocompatible material such as PMMA (polymethyl methacrylate) material. However, one of the present problems with intraocular lenses is that it is necessary to decide on the power of the lens preoperatively. This can be accomplished, for example, by performing an ultrasound scan and/or evaluating the patient's refraction preoperatively and then making a clinical estimate of the proper power of the lens in order to determine proper refraction of the eye. However, even with the best medical techniques and sophisticated optical instruments available, ophthalmologists have never been able to correct for accommodation which is the ability to change the focus of vision from distance to near vision and there is no lens system that can be adjusted after implantation for even minor changes in spherical or astigmatic power. Thus, most patients, following routine lens implantation, require the use^" of glasses for precisely focused distance and near vision.

The prior art intraocular lens typically is either of plano-convex construction or double convex construction, with each curved surface defining a spherical section. The lens is placed in the eye through the same incision which is made to remove the cataract lens. As noted above, this incision typically is made along the superior part of the eye near the juncture of the cornea and the sclera. About one third of all postoperative patients will have significant astigmatism and, approximately one third will need a spherical adjustment in their postoperative glasses to see clearly. In virtually all instances, the surgery itself induces astigmatism which fluctuates significantly during the first few weeks, or even months, after the surgery.

Postoperative induced astigmatism is attributable to the healing characteristics of the eye adjacent the incision through which the cataract lens is removed and the intraocular lens is inserted. More particularly, the incision in the eye tends to heal slowly. The incision in the eye may take eight weeks to a year to properly heal. During the period when the eye is healing, the wound area tends to spread and thus a cornea that may have been spherical before surgery is made other than spherical.

Since the incision is generally horizontally aligned, the spreading is generally along the vertical meridian. Initially, after the surgery, the cornea is relatively steep in the vertical meridian. As the eye heals, the cornea becomes relatively flat in the vertical meridian. Consequently, the optical system of the eye, which may previously have been spherical, becomes "toric" with the vertical meridian of the optical system providing a different optical power than the horizontal meridian. This non-spherical configuration of the optic system is generally referred to as "astigmatism".

The degree of this induced astigmatism varies according to the type of incision made, the presence or absence of sutures or the number and type of sutures used, the technical skill and care employed by the surgeon, and the physical attributes of the eye. For example, the use of a fine nylon suturing material typically results in a smaller deviation from sphericity than the use of silk or absorbable sutures. Generally, the induced astigmatism varies from 0.5 to 5 diopters. The initial postoperative astigmatism is generally caused by the steepening of the vertical meridian. Late astigmatism is caused by the flattening of the vertical meridian of the cornea. The orientation and amount of postoperative astigmatism are, in most cases, not accurately predictable. Postoperative astigmatism typically is corrected by prescription eyeglasses which need to be changed periodically as the eye heals.

In some cases, despite the best efforts of the ophthalmologist, the lens surgically placed in the patient's eye does not provide good distance visual acuity due to spherical miscalculations and due to the changing astigmatic requirements. Since the surgery itself can cause significant change in the amount and axis of the astigmatism present after cataract surgery, the exact amount and axis of astigmatism can not be accurately determined until sometime, usually several weeks or months, after the surgery. Since the old intraocular lens can not be readily removed and a new intraocular lens with a different power surgically installed without unduly jeopardizing the patient's vision, the patient must rely on spectacles to provide accurately focused visual acuity. In other words, although the need to wear heavy, bulky, higher power spectacles is eliminated, the patient nevertheless usually must wear spectacles for best focused vision.

Several attempts have been made to provide an intraocular lens which corrects for the astigmatism expected after surgery or can be varied in power after implantation. U.S. Patent No. 4,575,373 discloses a laser adjustable intraocular lens which utilizes a laser to alter, in situ, the power of an implanted intraocular lens. The outer ring of the lens is manufactured of a non-toxic heat shrinkable colored plastic material to permit selective absorption of laser energy, thereby causing the shape of the lens to change increasing the power non-reversibly.

U.S. Patent No. 4,816,031 discloses an intraocular lens system including a PMMA lens implant, a second soft and pliable lens positioned thereover, and electromechanical circuitry for regulating the distance between the two lenses, thereby providing for adjustment of the focal point of the lens system. U.S. Patent No. 4,601,722 discloses an intraocular lens having a lens body formed of a .plurality of lens body portions and magnet means for the assembly of the portions into the lens body within the eye after the portions are individually inserted through an incision in the eye. U.S. Patent No. 4,512,039 discloses an intraocular lens for offsetting postoperative astigmatism having the finally placed vertical meridian optically weaker than the horizontal meridian. Proper placement is ensured by disposing the haptics along the vertical meridian. U.S. Patent No. 4,298,996 discloses a magnetic retention system for an intraocular lens having one or more supports extending from the lens body. Each support carries a pair of magnetic fixation members positioned on opposite sides of the iris, whereby a trans-iris magnetic force secures the lens in place without sutures or incisions in the iris.

U.S. Patent No. 4,277,852 discloses an intraocular lens with astigmatism correction combined with a supporting mount or haptic structure to assure correct optical orientation of the implant.

Several attempts have been made to provide a variable power intraocular lens, which power varies according to an application of a force external to the lens, for correcting the astigmatism expected after surgery. U.S. Patent No. 4,787,903 discloses an intraocular lens including an annular Fresnel (prism) lens, made of a high index of refraction material such as polymethylmethacrylate. A composite material overlays the Fresnel elements to provide a smooth external surface and is made of a suitable material, for example, crystalline lattice or liquid crystal material, which changes the index of refraction when excited with electrical power or radiant energy. The lens carries a complementary loop or other energy pick-up device, for receiving the power from an electric field generated by an external power source feeding a coupling loop. The coupling loop can be carried in an eyeglass frame, implanted about the eye socket or positioned by the lens wearer or an ophthalmologist. It is stated in the patent specification that some overlay materials can be switchable between more than two states, each with a different index of refraction, while other materials will provide a continuously variable index of refraction which may be stable or may return to an initial value when the energy is removed. However, such materials are not identified in the patent.

U.S. Patent No. 4,601,545 discloses a variable power lens system including an optically active molecular material such as liquid crystals. A variable gradient index of refraction is achieved by applying a controlled stimulus field, such as a geometrically configured matrix of electrical voltages, to the lens. A corresponding matrix of horizontal and vertical conductors applies the electrostatic field produced by the applied voltage to be selectively controlled at discrete points so that a gradient index of refraction is produced. U.S. Patent No. 4,564,267 discloses a variable focal length lens which can be electrically controlled by applying an electric field to a compound lens including at least one lens formed of electrooptic crystals. The electrooptic crystals are juxtaposed between first and second transparent electrode plates each comprising a plurality of concentric annular transparent electrodes. A power source connected to the electrodes generates an electric field across the crystals creating a refracting index distribution having a lens action. The electric field effectuates a change in the focal length of the lens which varies according to the potential imparted.

U.S. Patent No. 4,373,218 discloses a variable power intraocular lens including a fluid expandable sac for containing a liquid crystal material that is used in combination with an electrode and a microprocessor for changing the index of refraction of the lens. An electrode is located in a ciliary body to provide an input signal that is proportional to a desired accommodation to a microprocessor which can be implanted into a sclera of a human eye. The microprocessor produces a potential across the liquid crystal material to control the index of refraction to obtain the desired accommodation based upon the relative position of the eyes. The voltage output of the micrc ocessor is applied to electrodes which can be a thin transparent material forming a coating on the interior of the fluid expandable sac.

SUMMARY OF THE INVENTION

In recent years, exploratory surgery and radiography have been replaced by magnetic resonance imaging (MRI) as a method of seeing inside the human body. The body is subjected to a powerful magnetic field which aligns the atoms of the body in a north-south orientation. An FM radio signal is transmitted through the body vibrating the molecules until they flip upside down. When the radio signal is terminated, the molecules flip back turning each atom into a tiny FM radio station whose signals are detected by an MRI scanner. It is an object of the present invention to change the focal power and astigmatism correction of a lens in an eye, in much the same manner as MRI, by applying an external force field which aligns actuating means in the lens. The present invention concerns an intraocular lens having a flexible lens body center portion formed from an optically clear m?terial surrounded by an outer ring which is sensitive to an external force field, such as a magnetic force. Utilizing the external force field, the shape of the outer ring can be changed to elongate the lens body along a predetermined axis for correcting astigmatism. The outer ring can also be used to change the power of the lens by altering the spherical shape of the lens.

In general, an intraocular lens apparatus, according to the present invention, for implantation into an eye includes an optically clear, flexible, generally circular lens body having a periphery; a relatively rigid ring having an inner periphery attached to the periphery of the lens body; and actuating means attached to one of the lens body and the ring for selectively and reversibly altering a shape of the lens body and maintaining an altered shape to adjust one or more characteristics of the lens body including the power and astigmatism correction, the actuating means being responsive to a presence of an external force field for altering the shape of the lens body.

The present invention concerns an adjustable focus lens which can be formed as an intraocular lens implanted in the human eye. The lens apparatus includes a transparent lens body having a periphery; a mounting ring extending about at least a portion of the periphery of the lens body; and a plurality of micromotor means spaced equally about and coupled between the ring and the periphery of the lens body. Each of the micromotor means is responsive to an external control signal for selective action to change position and/or the diameter and/or circumference of an associated portion of the lens body periphery for power and astigmatism correction. Power to operate the micromotors can be supplied from an external source and/or stored when the lens^' apparatus is implanted for later use.

In one embodiment, the lens apparatus includes an expandable and contractible inner ring and a relatively rigid outer ring, the micromotor means being attached to the outer ring and adjustably engaging the inner ring. The micromotor means can be formed as a tuning fork having a pair of generally parallel prongs extending on either side of the inner ring and connected to a base attached to the outer ring. The inner ring has a pair of flanges formed thereon and facing surfaces of the prongs have grooves formed therein for releasably retaining the flanges. The micromotor means also can include a linear positioning device connected between the base of the tuning fork and the inner ring. Power for the micromotor means can be provided from an external source which can be ultrasound, static electricity, magnetic field, laser beam, etc. Power for the micromotor means also can be stored, as potential energy for example, in the micromotor means before implantation for later use.

In another embodiment, the mounting ring is formed of a plurality of segments and the micromotor means controls overlapping portions of the segments wherein facing surfaces of the overlapping portions have cooperating grooves formed therein. The lens body has a hollow edge portion formed at the periphery thereof and the overlapping portions extend through the hollow edge portion. The micromotor means acts to change the circumference of the ring thereby changing the configuration of the lens body.

In other embodiments, the micromotor means can include a fluid powered piston and cylinder system, a helical groove or thread and cooperating nut system, or a track and motive means system coupled between inner and outer rings. These systems permit relative axial and/or radial movement between adjacent portions of the two rings thereby changing the position or configuration of the lens body in the eye.

In an intraocular lens application, the postoperative vision of the lens implant recipient may be repeatably corrected or adjusted to perfect or near perfect vision. The changed power and/or astigmatism correction of the lens remains stable until such time the implant recipient needs to have the external force field applied to correct a deviation from perfect vision caused by other sources (such as the changes in astigmatism common in the healing process) thus eliminating the need for changes in glasses to keep the eye in good focus. Furthermore, due to the passive restraint system in place, the lens according to the present invention is stable, retaining the focus and/or astigmatism correction after the external force field has been removed. Such lens does not require a continuous power source, nor a power source being coupled to the lens material by circuitry and a matrix of electrodes, nor power coupling loops to supply continuous power to the lens. The lens can be easily adjustable: adding or subtracting spherical lens power or adding or subtracting astigmatic lens power thus fine tuning the lens focus as needed as often as necessary over the life of the patient. The present invention concerns an adjustable focus lens which can be formed as an intraocular lens implanted in the human eye. The lens apparatus includes a transparent and flexible lens body having a periphery; means for mounting the lens body in an eye such as legs, a loop or a ring; and a selective position and orientation control device in the form of a plurality of micromotor means spaced equally about and connected between the periphery of the lens body and the mounting means, each of the micromotor means being responsive to a predetermined external source of energy (such as ultrasound) for selectively changing the position of the lens body or a portion thereof in the eye for power and astigmatism modification.

In one embodiment, the means for mounting includes an expandable and contractible inner ring formed at the periphery of the lens body and a relatively rigid outer ring, the micromotor means being connected between the outer ring and the inner ring. In another embodiment, the means for mounting can be a pair of loops having ends connected to a periphery of the lens body by the micromotor means. In yet another embodiment, the means for mounting is a pair of hooks having ends attached to the periphery of the lens body by the micromotor means. The micromotor means can be a^" linear positioning device having a base attached to the outer ring, loop or hook and an extendable rod attached to the lens body. Power for the micromotor means can be provided from an external source which can be ultrasound, static electricity, magnetic field, laser beam, etc. In addition, potential energy can be stored, for example, in the outer ring or the linear positioning device for use after implantation in response to an external triggering device.

In an intraocular lens application, the postoperative vision of the lens implant recipient may be repeatably corrected or adjusted to near perfectly focused vision. The changed power and/or astigmatism correction of the lens remains stable until such time the implant recipient needs to have the external force field applied to correct a deviation from perfect vision caused by other sources (such as the changes in astigmatism common in the healing process) thus eliminating the need for changes in glasses to keep the eye in good focus. Furthermore, due to the passive restraint system in place, the lens according to the present invention is stable, retaining the focus and/or astigmatism correction after the external force field has been removed. Such lens does not require a continuous power source, nor a power source being coupled to the lens material by circuitry and a matrix of electrodes, nor power coupling loops to supply continuous power to the lens. The lens can be easily adjustable: adding or subtracting spherical lens power or adding or subtracting astigmatic lens power thus fine tuning the lens focus as needed as often as necessary over the life of the patient.

BRIEF DESCRIPTION OF THE DRAWINGS The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:

Fig. 1 is a cross-sectional side elevational view of a normal human eye prior to removal of the natural lens;

Fig. 2 is a front elevational view of a typical prior art intraocular lens;

Fig. 3 is a cross-sectional view of the lens shown in the Fig. 2 taken along the line 3-3 on the vertical meridian;

Fig. 4 is a cross-sectional view of the lens shown in the Fig. 2 taken along the line 4-4 on the horizontal meridian;

Fig. 5 is a cross-sectional side elevational view of the human eye shown in the Fig. 1 after the insertion of the intraocular lens shown in the Fig. 2; Fig. 6 is a front elevational view of an intraocular lens apparatus in accordance with the present invention;

Fig. 7 is a cross-sectional view of the lens apparatus shown in the Fig. 6 taken along the line 7-7; Fig. 8 is a front elevational^' view of an intraocular lens apparatus in accordance with a first alternate embodiment of the present invention;

Fig. 9 is a cross-sectional view of the lens apparatus shown in the Fig. 8 taken along the line 9-9;

Fig. 10 is a front elevational view of an intraocular lens apparatus in accordance with a second alternate embodiment of the present invention;

Fig. 11 is a cross-sectional view of the lens apparatus shown in the Fig. 10 taken along the line 11-11; Fig. 12 is a cross-sectional view of the lens apparatus shown in the Fig. 10 taken along the line 12-12; Fig. 13 is a front elevational view of an intraocular lens apparatus in accordance with a third alternate embodiment of the present invention;

Fig. 14 is a cross-sectional view of the periphery of the lens apparatus shown in the Fig. 13 taken along the line 14-14;

Fig. 15 is an enlarged fragmentary view of a portion of the ring of the lens apparatus shown in the Fig. 14; Fig. 16 is an enlarged fragmentary rear elevational view of the flexible lens body of the lens apparatus shown in the Fig. 14;

Fig. 17 is a front elevational view of an intraocular lens apparatus in accordance with a fourth alternate embodiment of the present invention; Fig. 18 is a fragmentary front elevational view of the lens apparatus shown in the Fig. 17 set for increased power;

Fig. 19 is a fragmentary front elevational view of an intraocular lens apparatus in accordance with a fifth alternate embodiment of the present invention;

Fig. 20 is a front elevational view of an intraocular lens apparatus in accordance with a sixth alternate embodiment of the present invention; Fig. 21 is an enlarged fragmentary view of the selectively adjustable shape retainer included in the lens apparatus shown in the Fig. 20;

Fig. 22 is a cross-sectional view of a portion of the periphery of the lens apparatus shown in the Fig. 21 taken along the line 22-22;

Fig. 23 is a fragmentary front elevational view of an intraocular lens apparatus in accordance with a seventh alternate embodiment of the present invention;

Fig. 24 is a schematic block diagram of a basic control apparatus for operating the actuator bodies in each of the lens assemblies according to the present invention;

Fig. 25 is a front elevational view of an instrument used with the control apparatus shown in the Fig. 24; and Fig. 26 is a schematic block diagram of an automated control apparatus for operating the instrument shown in the Fig. 25 and the actuator bodies in each of the lens assemblies according to the present invention. Fig. 27 is a front elevation view of an intraocular lens apparatus in accordance with the present invention;

Fig. 28 is an enlarged cross-sectional view of a portion of the lens apparatus shown in the Fig. 27 taken along the line 7-7;

Fig. 29 is an enlarged cross-sectional view of a portion of the lens apparatus shown in the Fig. 27 taken along the line 8-8;

Fig. 30 is a front elevation view of an alternate embodiment of the intraocular lens apparatus according to the present invention;

Fig. 31 is an enlarged cross-sectional view of a portion of the lens apparatus shown in the Fig. 30 taken along the line 10-10 ; Fig. 32 is an enlarged cross-sectional view of a portion of the lens apparatus shown in the Fig. 30 taken along the line 11-11;

Fig. 33 is an enlarged cross-sectional view of a second alternate embodiment of a micromotor for the lens apparatus shown in the Fig. 28;

Fig. 34 is an enlarged cross-sectional view of a third alternate embodiment of a micromotor for the lens apparatus shown in the Fig. 28; and

Fig. 35 is an enlarged cross-sectional view of a fourth alternate embodiment of a micromotor for the lens apparatus shown in the Fig. 28. Fig. 36 is a front elevation view of an intraocular lens apparatus having a ring type attachment device in accordance with the present invention;

Fig. 37 is a front elevation view of an alternate embodiment of the intraocular lens apparatus according to the present invention having a pair of loop type attachment devices;

Fig. 38 is an enlarged cross-sectional view of a portion of a second alternate embodiment of the intraocular lens apparatus according to the present invention having a leg type attachment device;

Fig. 39 is an enlarged cross-sectional view of a portion of a third alternate embodiment of the intraocular lens apparatus according to the present invention having a leg type attachment device;

Fig. 40 is a block diagram of a system for testing and storing data to be used to selectively position and orient the intraocular lens apparatus according to the present invention; and Fig. 41 is a block diagram of a system for selectively positioning and orienting the intraocular lens apparatus according to the present invention after implantation in the eye.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Fig. 1, there is illustrated a normal human eye generally indicated by the reference numeral 10. The eye 10 includes a cornea 12 covering an opening in a generally spherical sclera 14. Positioned interiorly of the cornea 12 in the opening in the sclera 14 is an iris 16 having a pupil 18. Positioned behind the pupil 18 is a lens 20 which focuses entering light onto a retina 22 on the interior surface of the eye, the retina being connected to the brain (not shown) by an optic nerve 24. The lens 20 is located centrally behind the pupil 18 and is protected by the cornea 12. In the normal eye 10, the lens 20 is clear and is substantially symmetrical, with opposed convex surfaces defining generally spherical sections. The lens 20 and the cornea 12 cooperate to focus incoming light on the retina 22. The retina 22 in turn cooperates with the optic nerve 24 and the brain, so that light impinging on the retina 22 is perceived as an image.

The light refraction which takes place in the cornea 12 and the lens 20 translates into an optical correction of about sixty diopters, with the cornea 12 accounting for about forty diopters and the lens 20 accounting for about twenty diopters. Other refracting structures also are present in the eye 10, but are disregarded here to simplify the explanation.

A cataract is a condition where the normally clear natural lens 20 of the eye 10 becomes progressively opaque. This opacification typically occurs over an extended period of time, and the amount of light which passes through the lens 20 decreases with increasing degrees of opacity. As the ability of the cataract lens 20 to transmit light decreases, the ability of the eye 10 to perceive to images also decreases. Ultimately, blindness can result. Since there are no known methods for eliminating the opacity of a cataract lens 20, it generally is necessary to surgically remove the opaque lens 20 to permit the unobstructed passage of light through the pupil 18 to the retina 22. The cataract lens 20 is removed through a generally horizontal incision made at the superior part of a juncture 26 where the cornea 12 and the sclera 14 meet.

Once the cataractous lens 20 has been surgically removed, light can be readily transmitted through the pupil 18 and toward the retina 22. However, the lens 20 performs a significant light focusing function. Consequently, with the lens 20 removed, the optical system of the eye is left about twenty diopters "short", and light is no longer properly focused on the retina 22. When a lens 20 is removed to eliminate cataracts, it must be replaced by an artificial lens. An intraocular lens, such as a prior art intraocular lens 28 shown in the Fig. 2, is commonly employed after cataract surgery to refocus the light on the retina 22.

The intraocular lens 28 can be constructed of any biologically inert, transparent material suitable for optical correction such as, for example, silicone. The lens 28 is a section of a sphere, generally circular as viewed from the front with a diameter of approximately six millimeters. A pair of haptics 30 function as legs or stabilizing loops which support the lens 28 in the proper position in the posterior chamber of the eye 10 (Fig. 5) . Each haptic 30 extends approximately four millimeters from a straight end attached to a periphery of the lens 28 to a curved end to be attached to the eye. Thus, the total width of the lens 28 and the haptics 30 is approximately fourteen millimeters.

The intraocular lens 28 is inserted behind the iris 16 as illustrated in the Fig. 5. This type of lens is referred to as a posterior chamber lens, the latest and most popular of the many designs of intraocular lenses. It should be understood that the prior art lens 28 can be manufactured for positions in the eye other than the posterior chamber. For example, the lens 28 can be placed in the anterior chamber, the area between the cornea 12 and the iris 16. However, such positioning is sometimes considered undesirable because positioning the lens very close to the cornea may result in traumatization of the endothelium of the cornea. A problem associated with the proper implantation of an intraocular lens is the accurate postoperative determination of the exact prescriptive or refracting power of the lens to be placed in the eye of the patient. The ophthalmologist or optometrist can, for example, attempt to estimate the prescriptive power of the natural lens 20 of the patient and, through the use of various measuring devices, e.g. ultrasound, measure the depth and diameter of the eye 10. These measurements in conjunction with clinical experience permit the ophthalmologist or optometrist to relatively accurately determine the proper refraction or power of the intraocular lens 28 to be implanted. In some cases however, despite the best efforts of the ophthalmologist or optometrist, the lens surgically placed in the eye is not the correct dioptric power and the patient does not obtain good unaided visual acuity. During the postoperative healing period, the patient has a variable amount of astigmatism, a refracting defect which prevents focusing of sharp distinct images. Some astigmatism present after cataract surgery is due to the surgical incision and changes in corneal curvature as a consequence of the healing of the incision. The curvature in the lens 28 can be formed asymmetricly such that a vertical meridian, along a cross section line 3-3 as illustrated in the Fig. 3, is optically weaker (longer diameter for less curvature) than an horizontal meridian along a cross section line 4-4 as illustrated in the Fig. 4. The thickness of the lens 28 at a center 28a remains constant. Thus, the difference in the respective optical strengths of vertical and horizontal meridians is created by different structural contours (such as different radii of curvature) , 28b and 28c, in the vertical and horizontal meridians respectively resulting in different light refracting characteristics. Thus, the lens 28 defines a section of a sphere. In order to properly align the lens 28 at the time of insertion in the eye, the haptics 30 are offset from and extend generally parallel to the vertical meridian. Thus, as explained above, the prior art intraocular lens 28 has a fixed correction and angle for astigmatic power as well as a fixed spherical power.

Thus, the prior art intraocular .lens 28 has a fixed correction for astigmatism and a fixed power. In the Figs. 6 and 7, there is shown an intraocular lens apparatus 32 which, according to the present invention, is provided with means for selectively changing the power of the lens and means for selectively providing correction for astigmatism. The lens apparatus 32 includes a central lens body 34 formed of a transparent flexible material and attached about a periphery thereof to an inner periphery of a ring 36 formed of a more rigid material. A pair of the haptics 30 can be attached to the ring 36.

Actuating means, in the form of a plurality of actuator bodies 38, are equally spaced about the circumference of the ring 36. The bodies 38 can be attached to a surface of the ring 36 or embedded when the ring is formed. The bodies 38 are formed of a magnetizable material such that each individual body functions as a permanent magnet having a north pole and a south pole. If adjacent ones of the bodies 38 are magnetized to repel, the ring 36 will be expanded and increase in circumference causing the lens body 34 to become less convex and, therefore, weaker in power. If adjacent ones of the bodies 38 are magnetized to attract, the ring 36 will be contracted and "decrease in circumference causing the lens body 34 to become more convex and, therefore, stronger in power. Thus, the actuator bodies 38 can be utilized to selectively control the power of the lens apparatus 32 after installation in the eye and will retain the selected shape of the lens body 36 until reset.

The degree of the astigmatism is readily determinable through the use of conventional methods. An external magnetic force can then be applied to predetermined ones of the bodies 38 to expand or contract a portion of the ring 36 aligned with the astigmatism to create the necessary toric shape.

The magnetic force required to magnetize the bodies 38 should be sufficient to prevent exposure to normal level everyday magnetic forces from resetting the lens 32.

In the Figs. 8 and 9 there is shown an alternate embodiment of the present invention. A lens apparatus 40 has a flexible central lens body 42 attached at a periphery thereof to an inner periphery of a more rigid ring 44. A plurality of magnetizable actuator bodies 46 are equally spaced about the ring 44 for selectively changing the power and the astigmatism correction as discussed with respect to the lens apparatus 32. However, portions 48 of the ring 44 positioned between the bodies 46 are formed with a reduced thickness as compared with adjacent portions which enclose the bodies. Thus, additional flexibility of the ring is achieved requiring less force to compress or expand the ring and change the shape of the lens body. A pair of the haptics 30 can be attached to the ring 44.

The lens bodies 34 and 42 of the lens assemblies shown in the Figs. 6-9 have a convex surface facing toward the pupil 18 and a concave rearwardly facing surface. Alternatively, a second alternate embodiment is shown in the Figs. 31-33 as a lens apparatus 50 having convex front and rear surfaces. A lens body 52 is formed from a transparent, somewhat flexible material with a circular shape in plan view and an ellipsoid shape in edge view. An annular groove 54 extends about the periphery of the body 52. Positioned in the groove 54 is a ring 56 having a plurality of magnetizable actuator bodies 58 embedded therein. If all adjacent actuator bodies are magnetized to attract or repel, the ring 56 will contract or expand respectively equally in all portions to selectively change the shape of the lens thereby changing the power of the lens. Also, two or three adjacent magnets can be magnetized to produce an astigmatism correction, either at opposite ends of a diameter to correct for regular astigmatism as illustrated in the Fig. 11, or at one end of the diameter to correct for irregular astigmatism as illustrated in the Fig. 12. A pair of adjacent bodies 58a and 58b have been magnetized to attract thereby changing the shape of the upper portion of the lens body 52 along the line 12-12 in the Fig. 10. A pair of the haptics 30 can be attached to the ring 56. A third alternate embodiment is shown in the Figs. 13-16 as a lens apparatus 60 having a flexible or malleable material (such as silicone) lens body 62 releasably attached to a rigid material (such as PMMA) ring 64. A pair of the haptics 30 can be attached to the ring 64. A plurality of spaced apart different diameter circumferential grooves 66 are formed in a forwardly facing surface 68 of the ring 64. The lens body 62 has a circumferential tongue 70 formed on an rearwardly facing surface 72 thereof. The grooves 66 and the tongue 70 can be formed with any suitable cross-sectional shape, such as the trapezoidal shape illustrated, provided that the grooves firmly retain the tongue to prevent separation of the lens body 62 from the ring 64. The power of the flexible or malleable lens body 62 can be changed selectively by moving the tongue 70 to an appropriate one of the grooves 66, the outermost one of the grooves resulting in the lowest power and the innermost one of the grooves resulting in the highest power. Movement between the grooves is accomplished by forming the grooves 66 with a plurality of interruptions or adjustment spaces 74. In a similar manner, the tongue 70 is segmented with each segment corresponding in position to and being of no greater length than one of the adjustment spaces 74. The lens apparatus 60 can be preset for any desired power prior to insertion in the eye by aligning the tongue 70 with a selected one of the grooves 66 and rotating lens body 62 with respect to the ring 64 to insert the tongue into that groove. If a change in power is required, the lens body 62 is rotated to align the segments of the tongue 70 with the adjustment spaces 74, the tongue is moved to the selected one of the grooves 66 for the power desired and the tongue is rotated into the newly selected groove. The entire tongue 70 can be formed of a magnetically responsive material or an actuator body 76 (Fig. 16) formed of magnetically responsive material can be embedded in each segment of the tongue. An external magnetic field can be utilized to move each of the actuator bodies 76.

In the Figs. 17 and 18, there is shown a fourth alternate embodiment of the present invention. A lens apparatus 78 includes a central lens body 80 attached at a periphery thereof to an inner periphery of a more rigid ring 82. A plurality of magnetizable actuator bodies 84 are equally spaced about the ring 82 for selectively changing the power and the astigmatism correction. The bodies 84 can be embedded in the ring 82 together with a means for retaining the shape of the lens apparatus 78 such as a shape retainer 86 formed of wire. The wire 86 extends circumferentially through the ring 82 between the bodies 84 and an outer periphery of the ring. A portion of the wire 86 between each of the adjacent pairs of bodies 84 extends inwardly toward the center of the lens apparatus 78 and turns sharply outwardly in a V-shape. If an external electromagnetic force is applied to a pair of adjacent ones of the bodies 84 tending to move the bodies together contracting the ring 82, at the same time, the V- shaped portion in the wire 86 between the adjacent bodies is made narrower. When the external force is removed, the wire 86 holds its new shape until the adjacent bodies 84 are moved again even if the bodies are not permanently magnetized. Thus, all of the bodies 86 can be moved to compress or expand the ring 82 thereby increasing and decreasing respectively the power of the lens apparatus 78. Furthermore, selected ones of the bodies 84 can be acted upon to produce astigmatism correction in the desired area of the lens apparatus 78. An example of the ring 82 contracted from the shape shown in the Fig. 17 is shown in the Fig. 18.

In Fig. 19, there is shown a fifth alternate embodiment of the present invention. A lens apparatus 88 includes the lens body 80 from the previous embodiment attached at a periphery thereof to an inner periphery of a ring 90. The ring 90 has embedded therein a plurality of the actuator bodies 84 and the shape retainer 86. An outer periphery 92 of the ring 90 has a plurality of V- shaped notches 94 formed therein adjacent the V-shaped portions of the shape retainer 86 in order to render the ring 90 more responsive to compression and stretching. Thus, the ring 90 is more flexible, requiring less force to contract or expand than the previously described ring 82.

There is shown in Figs. 20-22, a sixth alternate embodiment of the present invention. A lens apparatus 96 has a flexible central lens body 98 attached at a periphery thereof to an inner periphery of an inner ring 100. A plurality of magnetizable actuator bodies 102 are equally spaced about the ring 100 for selectively changing the power and the astigmatism correction as discussed with respect to the other lens assemblies above. However, an outer periphery of the inner ring 100 is attached to an inner periphery of an outer ring 106 having a shape retainer 104 embedded therein. The shape retainer 104, as more clearly seen in Fig. 21, is of tubular shape and acts in an accordion fashion to lengthen and shorten. When two adjacent ones of the actuator bodies 102 are moved toward one another or away from one another, the inner ring 100 and the outer ring 106 tend to contract and expand respectively. The shape retainer 104 is also contracted or expanded and is formed of a material which retains its position until it is again forced to move by the bodies 102. Thus, the power and the astigmatism correction for the lens 96 can be controlled through the movement of the actuator bodies 102 and the shape retention capabilities of the shape retainer 104.

There is shown in Fig. 23, a seventh alternate embodiment of the present invention based upon the lens apparatus 96 shown in Fig. 20. A lens apparatus 108 utilizes the lens body 98, the inner ring 100, the actuator bodies 102 and the outer ring 104 as described above. However, the shape retainer 104 has been replaced with a helically formed wire shape retainer 110 which retains its shape once set by the movement of the actuator bodies 102.

There is shown in the Fig. 24 a block diagram of a control system for operating the actuator bodies in each of the above-described lens assemblies. A power supply 112 has an output connected to an input of a field strength control 114. An output of the field strength control 114 is connected to a first coil 116. A second output of the field strength control 114 is connected to a second coil 118. Each of the coils 116 and 118 can be mounted on a holder 120. The holder is any suitable device for positioning the coils 116 and 118 adjacent associated ones of the actuator bodies in any of the above-described lens assemblies. The field strength control 114 is selectively adjustable for applying a wide range of electrical power to each of the coils 116 and 118 individually in order to either permanently magnetize or simply move the associated body in accordance with the method of operation of one of the lens assemblies according to the present invention. The coils 116 and 118 are representative of either a single coil which can be separately aligned with each of the actuator bodies in turn or any other number of such coils including a separate coil for each of the actuator bodies such that all of the actuator bodies in a lens apparatus can be operated at the same time.

As shown in the Fig. 25, the holder 120 can form a portion of an instrument 122 for operating the actuator bodies of a lens apparatus according to the present invention. The holder 120 can be ring-shaped having a center aperture 124 which can be utilized to align the instrument 122 with one of the lens assemblies according to the present invention installed in the human eye.

Mounted on the ring-shaped holder 120 are the coils 116 and 118, each of the coils being positioned in alignment with an associated one of the actuator bodies in the lens apparatus to be operated. Additional coils 126 mounted on the holder 120 are shown schematically and represent any desirable number of such coils. The coil 116 is connected by a pair of lead wires 128 to any suitable control such as the field strength control 114 shown in Fig. 24. Similarly, the coil 118 is connected by a pair of lead wires 130 to a suitable control.

The polarity of the magnetic field generated by the coils 116 and 118 can be reversed by simply reversing the current flow through the associated wires 128 and 130. The coils 116 and 118 can also be provided with mechanical means for orienting them to selectively operate the actuator bodies in a desired manner. For example, the coil 116 can be mounted on a carrier 132 slidably retained in a circumferentially extending slot 134 formed in a face of the holder 124. The carrier 132 can be moved in either direction along the slot 134 to accurately position the coil 116 with respect to an associated actuator body. Alternatively, the coil 118 is shown mounted on a circular carrier 136 which is rotatably mounted on the holder 120. Thus, the angular orientation of the coil 118 with respect to a radius of the holder 120 can be selectively changed as desired.

The instrument 122 can be incorporated into a device which can be utilized by the patient to change the shape of the lens body as the situation requires. For example, the instrument 122 can be built into a pair of eyeglasses or formed as a handheld control and operated by the patient to change the lens focus between near vision and far vision

There is shown in the Fig. 26 a control for automatically operating the actuator bodies of any of the above-described lens assemblies according to the present invention. The previously described power supply 112 is connected to an input of a control unit 138. A pair of outputs of the control unit 138 are connected to the coils 116 and 118 which are mounted on the holder 120. The control unit 138 can include a general purpose, programmed microprocessor having a standard operating software system and a program for receiving instructions through a keyboard 140 connected to an input of a control unit 138 as to the strength and duration of the electrical power to be applied from the power supply 112 to the coils 116 and 118 in order to operate the actuator bodies as desired. In addition, a position sensor 142 can be connected to an input of the control unit 138 for generating a signal representing the position of the holder 120 and the coils 116 and 118 with respect to the lens apparatus to be operated. The position sensor 142 can be any suitable device, typically light sensitive, for detecting any of the physical features on the lens apparatus. For example, the position sensor 142 could detect the actuator bodies, a periphery of the lens body, or a periphery of the ring shown in any of the preceding lens apparatus embodiments. The actuator bodies can be formed of a ferromagnetic element or one of a variety of alloys of ferromagnetic and other elements which respond to a nearby magnetic field. In some cases, the actuator elements can be "permanently" magnetized, magnetized even though the external magnetic field is removed, or simply aligned in response to the alignment of the electromagnetic field where a shape retainer is employed. In summary, an improved intraocular lens is provided to eliminate or reduce the post-operative regular and irregular astigmatism. The invention utilizes an intraocular lens having a flexible center lens body surrounded by an outer ring having actuator bodies sensitive to an external force such as a magnetic field. Through the implementation of an external magnetic force, the shape of the lens can be changed to elongate the lens along a predetermined axis for correcting astigmatism. If the axis of the astigmatism changes, the shape of the lens can be changed by reapplying the force along a different axis. The ring can also be utilized to change the power of the lens, by changing the spherical shape. The utilization of such an intraocular lens may eliminate the need of the recovering cataract patient to wear eye glasses or contact lenses necessary. The elimination of the glasses or contact lenses amounts to an immense benefit to the recovering cataract patient, many of whom are elderly and have enough hardships without being burdened with wearing glasses or contact lenses. Furthermore, a source of the external force can be incorporated into a pair of eyeglasses, if needed, or a handheld device to be selectively operated by the patient for the accommodation of different focal lengths.

Although the actuator bodies have been described as formed of ferromagnetic material responsive to a magnetic field, such bodies could be formed of any suitable material responsive to electromagnetic or mechanical energy waves which cause the ring to compress and expand circumferentially.

The various lens apparatuses discussed above can be categorized as "active" or "passive" systems. The "active" systems (32, 46 and 50) require the application of a force field to the actuating means to selectively and reversibly alter the shape of the lens body. The actuating means then actively generates its own force field to maintain the selected shape. The "passive" systems (60, 78, 88, 96 and 108) also require the application of a force field to the actuating means to selectively and reversibly alter the shape of the lens body. However, the actuating means does not require any force field to maintain the selected shape. Any of the actuating means of the "active" systems and any of the actuating means of the "passive" systems in the embodiments shown and described can be substituted for each other as desired. Furthermore, any of the actuator segments shown can be mounted for rotation in the associated ring similar to the coil 116 and the carrier 136 shown in the Fig. 25. Such an actuator segment would remain magnetized and could be rotated by the instrument 122 to attract or repel an adjacent actuator segment or be oriented in a neutral position.

In the Figs. 27-29, there is shown a micromotor actuated variable focus intraocular lens apparatus according to the present invention generally indicated by a reference numeral 32, which lens is provided with means for selectively changing the spherical power of the lens and means for selectively providing correction for astigmatism. The lens apparatus 32 includes a central lens body 34 formed of a transparent flexible material, such as a silicone or the like. The lens body 34 is generally disc-shaped and has an anterior convex surface adapted to be centered in the pupil of an eye and planar rear surface. However, the anterior and rear surfaces can be any desired combination of concave, planar and convex. An inner ring 36 is attached about a periphery of the lens body 34 by any suitable means, such as being molded integral therewith as shown in the Fig. 28. The inner ring or rings 36 can be formed of any suitable elastomeric material to provide for appropriate expansion and contraction of its periphery with the abilities to become oval, segmented or wave like and the peripheral circumference depending upon the orientation of the micromotor. The ring 36 is retained by a plurality of spaced micromotors 38 extending radially inwardly toward the center of the lens body 3 . The micromotors 38 each have an inner end for retaining the inner ring 36 and an outer end attached to an outer ring 40 which extends concentrically about the inner ring 36. The outer supporting or mounting ring 40 is made from a rigid plastic or other material and provides a fixed support for the micromotors 38 and the lens body 34. A pair of haptics 30 can be attached to the ring 40 to support the lens apparatus 32 in the proper position in the eye.

As shown in the Fig. 28, each of the micromotors 38 can be formed as a tuning fork having a pair of spaced apart generally parallel .rongs or legs 42 and 44 branching from a base or handle 46 attached to the outer ring 40. Facing surfaces of the prongs 42 and 44 have grooves or teeth 48 and 50 respectively formed therein. The grooves 48 and 50 cooperate with a pair of opposed flanges 52 and 54 respectively formed on the inner ring 36 to retain the adjacent portion of the lens body 34 and the inner ring 36 a selected distance from the outer ring 40. If the inner ring 36 is expanded and increased in diameter, the lens body 34 will tend to become less curved and the power of the lens assembly 32 will be reduced. If the inner ring 36 is contracted and reduced in diameter, the lens body 34 will tend to become more curved and the power of the lens assembly 32 will be increased. The micromotors 38 cooperate with the inner ring 36 to provide selective adjustment of the power of the lens from outside the eye. Each of the micromotors 38 can be powered by a control signal from an external energy source, not shown, such as a source of ultrasonic energy at a predetermined controlled^'frequency and/or amplitude which tends to vibrate the prongs 42 and 44, oscillating them in the direction of the double headed arrows 58 and 60 respectively. This produces a wave action that can cause selective movement of the flanges 52 and 54 in the direction of the double headed arrows 58 and 60 respectively. As each of the prongs 42 and 44 moves horizontally, the associated flanges 52 and 54 will disengage from the grooves 48 and 50 respectively and then to reengage in a different groove further away or closer to the outer ring 40 depending on the externally controlled frequency and thus the propelling wave action generated longitudinally along the prongs 42 and 44. The micromotor 38 can be responsive to different amplitudes of ultrasonic energy: it can be responsive to ultrasonic energy at a first predetermined frequency for contracting and a second predetermined frequency for expanding the inner ring 36.

There is illustrated in the Fig. 29 an alternate embodiment of the micromotor 38. A micromotor 38^» is formed similarly to the micromotor ^*38, but includes a linear positioning device 64 located between the prongs 42 and 44. The positioning device 64 has a body 66 attached at one end to the base 46. A rod 68 extends from the opposite end of the body 66 and has a free end attached to the inner ring 36. The linear positioning device is responsive to a control signal from an external source of energy (not shown) for extending and retracting the rod 68 thereby moving the ring 36 in the direction of the arrow 62 to change the shape of the lens body 34. The source of energy can be ultrasonic as discussed above. The source of energy can be electromagnetic (laser beam, radio waves, etc.) . In either case, conventional devices are known for converting such energy into the linear motion 62. If all of the micromotors 38 and 38* are operated to maintain the inner ring 36 in a circular configuration, only the power of the lens assembly 32 will be changed. If individual ones of the micromotors are operated to change the shape of associated segments of the lens body 34, a selective correction for astigmatism can be made. One micromotor can be actuated to correct for irregular astigmatism and two opposing micromotors can be actuated to correct for regular astigmatism. Each of the micromotors 38 and 38' can be responsive to a different frequency for selective actuation or each micromotor can be selectively activated by external selective stimulation. In the Figs. 30-33 there is illustrated an alternate embodiment of the present invention. A lens apparatus 70 has a flexible central lens body 72 attached at a periphery thereof to a relatively rigid mounting or supporting ring 74 formed of a plurality of overlapping curved segments. Although only three segments 76, 78 and 80 are shown, the ring 74 can be formed of any suitable number of segments. The ring 74 can be attached to the periphery of the lens body 72, as discussed below with^" respect to the Fig. 31, or extend through a hollow edge portion of the lens body 72, as discussed below with respect to the Fig. 32. A pair of haptics 30 can be attached to the ring 74, one haptic 30 being attached to the segment 78 and the other haptic 30 being attached to the haptic 80.

Referring to the Fig. 31, there is shown an enlarged cross-sectional view of the overlapping segments 76, 78 and 80 which form a micromotor. On the facing surfaces of the overlapping portions of the segments 76 and 80 are formed cooperating grooves 82. On the facing surfaces of the overlapping portions of the segments 78 and 80 are formed cooperating grooves 84. The grooves 82 and 84 selectively permit relative motion between the associated segments thereby fixing the power and astigmatism correction of the lens apparatus 70 at selected values as explained below.

Referring to Fig. 32, there is shown a portion of the lens apparatus 70 wherein the segments 76 and 78 overlap to form a micromotor. On t^? e facing surfaces of the overlapping portions of the segments 76 and 78 are formed cooperating grooves 86 which selectively permit relative motion between the segments as explained below. The overlapping portions of the segments 76 and 78 slidably extend through a hollow edge portion 88 of the lens body 72.

The overlapping portions of the segments and the grooves shown in the Figs. 10 and 11 form micromotors 90 and 92 respectively. These micromotors are representative of a plurality of such elements which can be spaced about the periphery of the lens body 72 in a manner similar to the micromotors 38 and 38' shown in the Fig. 27. The more micromotors that are used, the more uniform will be the curvature of the lens body 72 and the more precise will be the ability to adjust spherical and astigmatism correction.

Relatively little sliding movement between overlapping segments is required to change the shape of the lens body 72. One means for achieving such movement would be to form the grooves 82, 84 and 86 such that vibration of a segment at a first frequency would cause relative movement in one direction between the segments and vibration at a second frequency would cause relative movement in the opposite direction. The vibration could be induced by externally applied ultrasonic energy. Another method of achieving such movement would be to induce magnetic poles in the segments which poles would be paired to attract or repel as required. In any case, the grooves selectively permit relative motion between the associated segments thereby fixing the power and astigmatism correction of the lens apparatus 70 at selected values. External mechanical pressure on the haptics 30 could be used to trigger a micromotor to cause circumferential movement of the overlapping ridges. If the micromotor has the capability to store potential energy, then external mechanical pressure on the haptics could be utilized to release such energy or to restore such energy. For example, a compressed spring located in the positioning device 64 could be released or recompressed.

There is shown in the Fig. 33 a micromotor 94 connected between the inner ring 36 and the outer ring 40. The micromotor 94 has a central body 96 which can be generally cylindrical in shape and capped at opposite ends by a pair of end walls 96a and 96b. One end wall 96b of the body can be attached to the outer ring 40. Extending from an opposite end of the body is a rod 98a having an exposed end attached to the inner ring 36. The rod 98a extends through the end wall 96a into a cylinder chamber 100a formed in the body 96. A piston 98b is slidably retained in the chamber 100a and is attached at an upper surface to an abutting end of the rod 98a. The cylinder 100a is filled with a fluid under pressure such as a gas, the gas in an upper portion of the cylinder being at a higher pressure which forces the piston 98b toward the lower end of the cylinder 100a.

Formed concentrically about the chamber 100a is a reservoir -00b filled with a compressible fluid under pressure. The upper end of the cylinder 100a is connected to an upper end of the reservoir 100b by a two-way valve 102a located in the end wall 96b. A lower end of the cylinder 100a is connected to a lower end of the reservoir 100b by a two-way valve 102b located in the body 96 and a radially extending passageway 104 formed in the end wall 96b. The reservoir 100b is divided into upper and lower portions by an annular piston 106. The piston 106 can be responsive to a control signal such as an external source of power for actuation to move in a downward direction decreasing the pressure on the fluid in the upper portion of the reservoir 100b and increasing the pressure on the fluid in the lower portion of the reservoir 100b. Fluid will flow from the upper portion of the chamber 100a through the valve 102a into the upper portion of the reservoir 100b and fluid will flow from the lower portion of the reservoir 100b through the passageway 104 and the valve 102b into the lower portion of the chamber 100a thereby forcing the piston 98b and the rod 98a in an upward direction as indicated by an arrow 108. Movement of the piston 106 in an upward direction will cause opposite movement of the piston 98b. Such movement of the piston 98b will cause relative displacement between the inner ring 36 and the outer ring 40 thereby causing a change of shape in the lens body 34. Other forms of reservoirs could be utilized such as flexible membranes responsive to external mechanical pressure for actuating the micromotor or recharging the fluid in the reservoir thereby storing energy for later use. External mechanical pressure or external triggers such as ultrasound or laser could be utilized to actuate a micromotor or the valves 102a and 102b, or recharge a reservoir, for example by making the fluid or gas in the chamber 100a expand thereby storing energy for later use.

There is shown in the Fig. 34 another embodiment of the present invention. A micromotor 110 has body 112 which can be generally cylindrical and have one end attached to the outer ring 40. A rod 114 extends through an end wall of the body 112 opposite the outer ring 40.

An outer end of the rod 114 is attached to the inner ring 36. An inner end of the rod 114 extends into a central cavity 116 which can be internally grooved or threaded in a helical pattern. Rotatably mounted on the rod 114 is an externally threaded nut 118 which threadably engages the wall of the cavity 116. In response to a source of external power, the nut 118 can be caused to rotate. If the nut 118 is fixed in position on the rod 114, then as the nut rotates and travels along the longitudinal axis of the cavity 116, the rod will be moved in the direction of a double headed arrow 120 to cause relative movement between the inner ring 36 and the outer ring 40 thereby changing the shape of the lens body 34. There is shown in the Fig. 35 ^"yet another embodiment of the present invention. A micromotor 122 has body 124 which can be of any suitable shape with an inner end attached to the inner ring 36. The micromotor 122 also includes a motive means 126 mounted on an outer end of the body 124 adjacent the outer ring 40. An annular track 128 is attached to the inner circumference of the outer ring 40 and has an inwardly facing helical groove 130 formed therein. The motive means 126 can be any suitable device such as a wheel or endless belt which can be moved along the groove 130 to rotate the lens body 34 about its center. The motive means 126 can be driven in a conventional manner in response to a source of external power and/or control signal to rotate the lens body 34 and move the lens body in the direction of a double headed arrow 132 thereby changing the axial position and functional power of the lens body 34 when installed in an eye. The micromotor 122 is representative of a plurality of such devices which can be spaced about the inner ring 36 in a manner similar to the micromotors 38 and 38' shown in the Fig. 27.

If the groove 130 shown in the Fig. 35 is formed as a plurality of annular grooves rather than a single helical groove and the lens body 34 and the inner ring 36 are formed of a flexible material, then astigmatism correction can De made. Openings (not shown) can be formed through the walls between adjacent grooves to permit the motive means 124 to travel between the grooves. If the grooves are formed with different depths, each of the motive means 124 can be moved individually to select the desired groove thereby changing the configuration of the associated portion of the inner ring 36 and the lens body 34 to provide astigmatism correction.

The utilization of such an intraocular lens in accordance with the present invention may eliminate the need of the recovering cataract patient to wear eye glasses or contact lenses. The elimination of the glasses or contact lenses amounts to an immense benefit to the recovering cataract patient, many of whom are elderly, sometimes forgetful, and many have financial and physical hardships. Furthermore, a source of the external force can be incorporated into a pair of eyeglasses, if needed, or a hand held device to be selectively operated by the patient, or the micromotor could be responsive to pressure applied from outside the eye to produce a change in the focal length (focus) so the lens would have accommodation (the ability to change focus from distance to near) . present invention has the advantage over prior art devices of not requiring a physical or electrical connection between the source of the power and the lens in order to change the lens.

The variable focus lens of the present invention has a variety of applications, in addition to the application as an intraocular lens. For example, the variable focus lens can be used as a camera lens. The lens could be used as an alternative to or in conjunction with cameras having either a fixed lens, an adjustable lens, or a plurality of interchangeable lenses.

In the Figs. 36-39, there are shown various embodiments of a micromotor actuated adjustable focus intraocular lens apparatus according to the present invention. In the Fig. 36, the apparatus is generally indicated by a reference numeral 32, which lens is provided with means for selectively changing the functional spherical power of the lens and for selectively providing correction for astigmatism. The lens apparatus 32 includes a central lens body 34 formed of a transparent flexible material, such as a silicone or the like. The lens body 34 is generally disc-shaped and has a convex surface adapted to be centered in the pupil of an eye and may have a concave, planar or convex rear surface. A periphery 36 of the lens body 34 can be formed as an inner ring of any suitable material to provide a stable mounting means for actuators. For example, the periphery 36 could be molded integral with the lens body 34, but thicker in cross section.

A plurality of spaced micromotors 38 extend radially inwardly toward the center of the lens body 34. The micromotors 38 each have an inner end attached to the inner ring 36 and an outer end attached to an outer ring 40 which extends concentrically about the lens body 34.

The outer re .g 40 is made from a relatively rigid material and provides a fixed support for the micromotors 38 and the lens body 34. The outer ring 40 supports the lens apparatus 32 in the proper position in the eye.

In the Fig. 36, if it is assumed that the lens assembly 32 is being viewed from the front, outside the cornea of the eye, then movement of the lens body 34 toward the viewer, the anterior direction, will increase the functional power of the lens based upon well known optical principles. Conversely, movement the lens body 34 toward the optic nerve, the posterior direction, will decrease the functional power of the lens assembly 32. The micromotors 38 cooperate with the inner ring 36 and the outer ring 40 to provide selective adjustment of the power of the lens from outside the eye. Each of the micromotors 38 can be powered by an external energy source, not shown, such as a source of ultrasonic energy at a frequency which causes extension action by the micromotors 38 equally moving the lens body 34 forward in a horizontal direction while maintaining the lens body 34 in a generally vertical plane. The application of energy at a different frequency will cause retraction action by the micromotors 38 equally moving the lens body 34 posteriorly in the horizontal direction while maintaining the lens body in the generally vertical plane.

There is shown in the Fig. 36 a radius 42 of the lens apparatus 32 extending outwardly from a center point 44 of the lens body 34 through one of the micromotors 38, a micromotor 38a. Any rotation of the lens body 34 about an axis in the plane normal to the path of light rays between the cornea 12 and the optic nerve 24 (Fig. 5) will cause an induced astigmatic effect for modifying astigmatism. If an irregular astigmatism which by its nature is segmental were located along the radius 42 and the lens body was made of flexible material, the micromotor 38a could be actuated to bend a segment of the lens body 34 relative to the remaining portion of the lens body. The more common variety of astigmatism is regular astigmatism which extends completely across the optical axis. Correcting regular astigmatism oriented along an axis 46 can be adjusted by activating the micromotors 38a in an anterior direction and 38c in a posterior direction, or visa versa.

Prior to implantation in the eye, the optical properties of the lens could be measured and stored in a computer, for example, with reference to the various combinations of actuation of the micromotors. After implantation in the eye, the data stored in the computer can be utilized along with postoperative information to guide the actuation of the micromotors to produce the desired dioptic power and astigmatic modifications. To correct for irregular and regular astigmatism and for dioptic power adjustments, micromotor manipulation may be aided by a computer program that calculates the amount of activation to be used on each micromotor by analyzing information from the following sources: corneal topography, corneal curvature radii, the refraction, axial length of the eye, and other ocular and lens data. There is illustrated in the Fig. 37 an alternate embodiment of the lens apparatus 32. A lens apparatus 48 includes the lens body 34 having the inner ring 36 attached to a plurality of micromotors 38. An attachment means in the form of a pair of loops 50 is attached to the lens body with an end of each of the loops 50 attached to an associated one of the micromotors 38. The lens apparatus 48 operates in a manner similar to the lens apparatus 32. In the Fig. 38 there is illustrated an alternate embodiment of the present invention. A lens apparatus 52 includes the lens body 34 having the periphery 36 thereof attached to one end of a generally horizontally extending one of the micromotors 38. The opposite end of the micromotor 38 is attached to one end of one of the legs 30. Thus, the micromotor 38 can be actuated in the direction of an arrow 54 thus changing the focal power and/or the astigmatic power of the lens body 34.

Referring to the Fig. 39, there is shown an enlarged cross-sectional view of another alternate embodiment of the present invention. A lens apparatus 56 includes the lens body 34 having the periphery 36 thereof attached to one end of a generally vertically extending one of the micromotors 38. The opposite end of the micromotor 38 is attached to one end of one of the legs 30. Thus, the micromotor 38 can be actuated in the direction of an arrow 58 to change the focal power and/or the astigmatic power of the lens body 34. If one end of the micromotor 38 is attached to the leg 30 by a pivot means 60 and the other end of the micromotor 38 is attached to the ring 36 by a pivot means 62, then the micromotor 38 can be actuated to extend, as shown in phantom, and move along a curved path as illustrated by an arrow 64.

The Fig. 40 is a block diagram of a system 66 for testing and storing data to be used to selectively position and orient the intraocular lens apparatus 32. A micromotor control device 68 individually controls the actuation of each of the micromotors provided in the lens apparatus 32. The micromotor control device 68 generates control signals and/or the power necessary to actuate the micromotors. At the same time, the control device 68 generates information signals to a computer 70 identifying which micromotors have been actuated. An optical sensing device 72 is provided for sensing the optical properties of the lens apparatus 32 and providing such information to the computer 70. The computer 70 stores the optical information from the sensing device in association with the control information from the control device 68 for later use.

The Fig. 41 is a block diagram of a system 74 for selectively positioning and orientating the intraocular lens apparatus 32 after implantation in the eye. When it is desired to change the functional power of the lens apparatus 32 and/or provide an astigmatism correction, the computer 70 will provide the necessary output signals to the micromotor device 68. The micromotor device 68 responds to the information from the computer 70 to generate the appropriate control signals and/or power necessary to actuate a predetermined combination of the micromotors in the lens apparatus 32 to produce the desired results.

Not only can the adjustment process described with respect to the Figs. 10 and 11 be performed in a doctor's office or medical facility, for example, but the system for selectively positioning and orientating the intraocular lens apparatus could be provided for use by the patient. The computer 70 and the micromotor control device 68 could be located in a pair of eye glass frames with controls for use by the patient. When the patient sensed a need to change the functional power, the patient would put on the glass frames, push an appropriate button, and the intraocular lens apparatus would be automatically changed. One example of such use could be when the patient wished to switch from distance vision to vision for close work such as reading or watch repair. The system according to the present invention could be provided so that it could be manipulated by the patient to self adjust the intraocular lens apparatus even providing adjustments for good vision as close as six inches from the work. The utilization of such an intraocular lens in accordance with the present invention may eliminate the need of the recovering cataract patient to wear eye glasses or contact lenses. The elimination of the glasses or contact lenses amounts to an immense benefit to the recovering cataract patient, many of whom are elderly, sometimes forgetful, and many have financial and physical hardships. The adjustable focus lens of the present invention has a variety of applications, in addition to the application as an intraocular lens. For example, the adjustable focus lens can be used as a camera lens. The lens could be used as an alternative to or in conjunction with cameras having either a fixed lens, an adjustable lens, or a plurality of interchangeable lenses.

In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.

Claims

WHAT IS CLAIMED IS:

1. An intraocular lens apparatus for implantation into an eye comprising: an optically clear, flexible, generally circular lens body having a periphery; a relatively rigid ring having an inner periphery attached to said periphery of said lens body; and actuating means attached to one of said lens body and said ring for selectively and reversibly altering a shape of said lens body and maintaining an altered shape to adjust characteristics of said lens body including the characteristics of power and astigmatism, said actuating means being responsive to a presence of an external force field for altering said shape.

2. The lens apparatus according to claim 1 wherein said actuating means includes a plurality of ferromagnetic material actuator bodies equally spaced about the circumference of said ring.

3. The lens apparatus according to claim 1 including an annular groove formed in said periphery of said lens body and wherein said ring is positioned in said groove.

4. The lens apparatus according to claim 1 wherein said ring has at least two circumferential grooves formed therein and said lens body has a tongue formed thereon, said tongue cooperating with said grooves to attach said lens body to said ring.

5. The lens apparatus according to claim 1 wherein said actuating means includes a plurality of ferromagnetic material actuator bodies equally spaced about the circumference of said ring and a shape retainer attached to said ring, said actuator bodies being responsive to a presence of an external magnetic field for altering said shape and said shape retainer maintaining said altered shape.

6. The lens apparatus according to claim 1 including a control system for operating said actuating means.

7. An intraocular lens apparatus for implantation into an eye comprising: an optically clear, flexible, generally circular lens body having a periphery; a relatively rigid ring having an inner periphery attached to said periphery of said lens body; and a plurality of actuator bodies attached to one of said lens body and said ring for selectively and reversibly altering a shape of said lens body and maintaining an altered shape of said lens body to adjust characteristics of said lens body including the characteristics of power and astigmatism, said actuator bodies being responsive to a presence of an external force field for moving said ring to define said altered shape.

8. An intraocular lens apparatus for implantation into an eye and a control system for operating the lens apparatus for changing the power and astigmatism correction of the lens apparatus comprising: an optically clear, flexible central lens body; a relatively rigid ring having an inner periphery attached to a periphery of said lens body; electromagnetic energy responsive actuator means attached to one of said lens body and said ring for altering the shape of said lens body to adjust the power and astigmatism correction of said lens body; and a control system for generating a selectively variable force field for operating said actuating means.

9. An adjustable focus intraocular lens apparatus, for implantation into an eye, comprising: a transparent lens body having a periphery; a mounting ring positioned adjacent to said periphery of said lens body; and micromotor means coupling said mounting ring to said periphery of said lens body, said micromotor means being responsive to an externally generated control signal for selectively changing at least one of the shape and the position of said periphery of said lens body to adjust the focus of the lens for power and astigmatism correction respectively.

10. The lens apparatus according to claim 9 wherein said periphery includes an expandable and contractible inner ring and said mounting ring includes a relatively rigid outer ring, said micromotor means being attached to said outer ring and releasably engaging said inner ring.

11. The lens apparatus according to claim 9 wherein said periphery and said mounting ring are formed of a plurality of ring segments and said micromotor means includes overlapping portions of said ring segments.

12. The lens apparatus according to claim 9 wherein said periphery includes an expandable and contractible inner ring and said mounting ring includes a relatively rigid outer ring, said micromotor means being attached to said outer ring and releasably engaging said inner ring, said micromotor means having a source of potential energy responsive to said control signal for actuating said micromotor means and moving said inner and outer rings with respect to one another.

13. An adjustable focus intraocular lens apparatus, for implantation into an eye, comprising: a transparent lens body having a periphery; an adjustable circumference ring attached to said periphery of said lens body; and a plurality of micromotor means spaced about and coupled to said ring, and responsive to an externally generated control signal for selectively changing the circumferential length of said ring to adjust the shape of the lens for power and astigmatism correction.

14. The lens apparatus according to claim 13 including a relatively rigid outer ring, wherein said ring includes an expandable and contractible inner ring, and each said micromotor means is formed as a tuning fork having a pair of generally parallel prongs extending on either side of and releasably engaging said inner ring and connected to a base attached to said outer ring.

15. The lens apparatus according to claim 13 wherein said ring is formed of a plurality of segments and each said micromotor means includes overlapping portions of at least two of said segments.

16. The lens apparatus according to claim 13 including a relatively rigid outer ring, wherein said ring includes an expandable and contractible inner ring, said micromotor means being attached to said outer ring and releasably engaging said inner ring, said micromotor means having a source of potential energy responsive to said control signal for actuating said micromotor means and moving said inner and outer rings with respect to one another.

17. An adjustable focus intraocular lens apparatus, for implantation into an eye comprising: a transparent lens body having a periphery; a mounting ring extending about said periphery of said lens body; and a plurality of micromotor means spaced equally about and attached to said mounting ring and coupled to said periphery of said lens body, each said micromotor means being responsive to an external control signal for selectively changing at least one of the circumferential length and axial position of an associated portion of said periphery of said lens body to adjust the lens for power and astigmatism correction.

18. An adjustable focus intraocular lens apparatus or implantation into an eye comprising: a transparent lens body having a periphery; an attachment means adjacent said periphery of said lens body; and micromotor means connected between said periphery of said lens body ring and said attachment means and responsive to an external control signal for selectively changing the position of said lens body with respect to a cornea and retina of an eye thereby adjusting the functional power and astigmatism correction of said lens body in the eye.

19. An adjustable focus intraocular lens apparatus or implantation into an eye comprising: a transparent lens body having a periphery; an attachment means adjacent said periphery of said lens body; and a plurality of micromotors connected between said periphery of said lens body ring and said attachment means and each responsive to an external control signal for selectively changing the position of an associated portion of said lens body with respect to a cornea and retina of an eye thereby adjusting the functional power and astigmatism correction of said lens body in the eye.

20. An adjustable focus intraocular lens system for selectively positioning and orienting a lens body after implantation into an eye comprising: a transparent lens body having a periphery; an attachment means adjacent said periphery of said lens body; a plurality of micromotors connected between said periphery of said lens body ring and said attachment means and each responsive to an external control signal for selectively changing the position of an associated portion of said lens body with respect to a cornea and retina of an eye thereby adjusting the functional power and astigmatism correction of said lens body in the eye; a control device external to the eye for generating said control signals; and a computer connected to said micromotor control device, said computer generating control data to said control device representing desired functional power adjustments and astigmatism corrections, said control device being responsive to said control data for generating said control signals.