CA1259452A

CA1259452A - Eye implant

Info

Publication number: CA1259452A
Application number: CA000476894A
Authority: CA
Inventors: Albert R. Richard
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-11-15
Filing date: 1985-03-19
Publication date: 1989-09-19
Also published as: GB8509855D0; CN85103328B; SE8501856L; BR8502042A; KR860003820A; DE3528258A1; NO158988B; SE8501856D0; IT1186713B; ES8607002A1; IN162737B; FR2572927A1; ES542141A0; IT8520940A0; NO850990L; CN85103328A; AU557565B2; GB2167306B; GB2167306A; AU4207085A

Abstract

ABSTRACT OF THE DISCLOSURE
An intraocular implant of the type having a lens and one or more flexible lens retaining legs extending therefrom for seating in an eye chamber, in which the free end of at least one of said legs has means for latching engagement with a cooperating latching portion on the periphery of the lens, which is so positioned circumferentially on the peripheral portion that when the end of the leg is latched therein, the leg is flexed around the edge of the peripheral portion so that the lateral dimension of the implant is substantially no greater than that of the lens and peripheral portion alone thereby facilitating insertion of the implant through an incision into the eye. In a preferred embodiment of the invention, the peripheral portion of the lens body has an upwardly projecting leg support member against which the leg bears when it is flexed around the lens body, which controls the amount of bending of the leg and distributes the bending throughout a substantial portion of the length of the leg.

Description

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i ~ACKG~OUND OF THE INVENTION
Intraocular lenses used as eye implants are well kncwn in the æ t.
l m P insertion of such a lens requires that an incision be made in the eye jl for the removal of the natural lens and insertion of the implant, which ,is formed of biological inert and transparent material such as polymethyl 'Imethacrylate m e length of the incision needed dep nds on the overall width of the lens to be inserted. Any reduction in the width of the implant would allow a reduction in the length of the incision, which is desirable since the smaller the incision, the less difficult is the post-operative recovery and healing period of the patient.
Although at least three retaining legs are considered desirable for such implants to insure reliable retention and centering, many such implants utilize only two flexible retaining legs, since implants with two legs ,can be made to pass through a narrGWer incision than an implant with three or more legs.
Another difficulty with such devices is the fact that even if they have only two legs, insertion of the device into the eye is difficult, since the first leg passed into the incision must be fleded against eye tissue t~
allcw the lens to be inserted far enough to allow the second leg to enter the incision and seat in the proper cavity m the eye.

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`1 SUMM~RY OF THE INVENTION
An intraocular implant is formed of plastic suitable for such purpose, such as polymethyl methacrylate, and camprises a lens body having a cen~er ` lens portion and a peripheral lens support portion disposed around the lens portion, and at least one flexible retaining leg extendiny from the peripheral lens support portion. In the un~restrained condition the flexible retaining leg extends around at least a portion of the peripheral portion in radial spaced relation thereto, terminating in a free end.
m e free end is prcvided with latching means, and the peripheral portion of the lens body is provided with cooperating latch means to receive the free end of the leg in releasable latching engagement. me cooperating latch on the lens body is so circumferentially positioned and the leg is so dimensioned that when the leg is flexed inwardly to enable the free end to be engaged with the latch, the leg lies along the outer edge of the peripheral portion, so that the overall width of the implant, when ready for insertion into the eye, is no greater than the width of the lens body alone.
In a preferred embodlment of the invention, a peripheral portion of the lens body is provided with upstanding lateral support means for the leg so positioned that when the leg is flexed around the body for attachment of the free end to the body, the leg bears against the lateral support means i which thereby controls the amount of inward flexing of the leg to distribute the flexing along a substantial portion of the leg and prevents excessive flexing at the root of the leg.
erefore an implant with any desired number of retaining legs can be provided, with means for attaching each leg to the lens body, so that the ` overall width of the implant is not increased by the presence of the legs.
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BRIEF DESCRIPTION OF I~E FIGURES OF T~E DRAWING

Figure 1 is a top plan view of an intraocular lens implant in the ,; I
as-manufactured condition, with the flexible retaining legs being un-restrained.
I Figure 2 is a view in side elevation of the implant of Figure 1.
¦ Figure 3 is a perspective view of the implant of Figure .
Figure 4 is a top plan view of the implant of Figure ] with the ;I flexible retaining legs latched onto the lens body in condition for insertion into the eye.
Figure 5 is a view of the device of Figure 4 in side elevation.
j Figure 6 is a view of the implant of Figure 4 after it has been inserted into the eye and the legs released.
Figure 7 is a top plan view of a m~dified form of implant em~odying the features of the invention, with the legs being in the unrestrained condition.
Figure 8 is a view of the device of Figure 7 in which the flexible legs Ihave been latched onto the body in preparation for insertion into the eye.

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i DESCRIPTI(~N OF TE.E IILUSI~ATEC E~DIMENrS
Referring to Figures 1-5 of the drawing, there is illustrated a first embodlment of the invention, which comprises an implant 10 cc~prisir~J
a lens body having a center lens portion 12 and a peripheral support portion 13, and a pair of resilient retaining legs 16.
The center lens portion 12 may be of any desired shape in transverse section to provide the desired lens effect. The peripheral portion 14 extends around the entire periphery of the lens 12, and is provided with an upwardly ex~ending rib ]8 which extends around the peripheral portion.
Each retaining leg 16 is an integral part of the peripheral por~ion and extends therefrom around the lens body in radial spaced relation thereto terminating in a free end 20 which has a laterally enlarged portion 22 having an aperture 24 therethrough. The legs 16 have a pr~ximal portion 26 which is tapered frcm the root (junction with the peripheral portion) to a position shown in Figure 1 as point "A", and a distal portion 28 of substantially uriform width from point "A" to the enlarged portion on the free end. This configuration of the retaining leg provides a portion of uniform thickness for seating in an eye chamber, yet allows the stress of bending to be distributed along the leg to reduoe the possibility of fracture of the leg at the root 26.
m e radius of curvature of the leg gradually increases from the root to the enlarged portion, with the portion 29 immediately adjacent to the enlarged portion being turned inwardly for a p~upose to be described.

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me rib 18 is provided with a pair of slots 30 extending therethrough in a generally radial direction, with each slot 30 being suit~bly positioned to receive the free end of a leg in a manner such that the enlarged portion 22 is disposed inside the rib and the adjacent portion of the leg being disposed in the slot. (See Figure 4).
In a preferred embcdiment of the invention, when the free ends 20 are so engaged in the slots, the rest of the leg is curved around the outer edge of the peripheral portion inside a circle concentric with said outer edge, as illustrated in Figure 4, which represents the implant in condition for insertion into the eye, and is maintained in this position by means to be described.
As illustrated in Figure 4, the implant, when the legs are latched onto the peripheral portion, has a width no greater than the peripheral portion alone, so that the use of the implant requires a minim~m length of surgical incision.
The implant will be supplied to the surgeon in the condition shown in Figure 1, with the legs un restrained and un-stressed. In preparation for insertion, the legs I6 will be flexed inwardly and the leg portions 29 adjacent the enlarged portion placed into the slots 30. The tendency of the flexed legs to resile will pull the enlarged portion snugly against the rib on opposite sides of the slot, so that the legs are ; retained in the flexed condition. After the implant has been inserted through the incision into the eye, the enlarged ends 22 may be lifted out of the slots 30 by a suitable tool so that they can resile outwardly into the surrounding eye chamber.
It will be understood that scme surgeons may prefer to attach the end of only one of the legs to the lens prior to insertion.

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l l In the embcdiment of Figures 1-5 the rib 18 is clivic~c1 into t~o ; portions by slots 30, each portion having an outer surface 32 which progresses radially inwardly as it approaches the slot, and each surface 32 is so positioned that as the leg is flexed inwardly for engagement with the rib, it kears against the surface 32, thereby reducing the amount of bencling force applied to the root of the leg at the point of attachment to the lens body The engagement of the leg with the surface 32 also controls the amount of bending of the distal portion of the leg, and provides support thereto to prevent damage to the leg during handling prior to and during insertion into the eye.
In many types of implants, the retaining legs are slightly inclined rearwardly in relation to the plane of the lens so as to maintain the lens in adesired position in relation to certain portions of the eye structure. In such case the legs 16 must be flexed slightly forwardly to allow the legs to be curved around the rib and latched into the slot 30. The legs will therefore be supported against downward flexing by the support portion 14 lying just outside the rib, so that the legs will be prevented from tending to become disengaged from the slot.
Referring now to Figures 7 and 8 of the drawin~, there is illustrated a modified form of implant embcdying the features of the invention. In this embcdlment, an implant 40 camprises a lens body which includes a , ~
center lens portion 42 and a peripheral portion 44, and three resilien-t retaining legs 46 extending frcm the peripheral portion around the lens body in spaced relation thereto. ~he peripheral portion 44 has three rib segments 48, each having a transverse slot 50 formed therein, which is circumferentially positioned to reoe ive the free end of a leg, so that the enlarged portion 52 thereon is retained on the inner side of the rib, as previously described in connection with the embodimen-t of Figures 1-5.

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i ~ hen the three legs 46 are flexed inwardly ~o curve around the outer edge of the peripheral portion and the end of the legs placed in the slots 50 so that the enlarged portion is retained on the inner side of the rib, the overall width of the implant is no greater than that of the lens body alone, so that the provision of three retaining legs on the lens body does not require a surgical incision any longer than if only two legs were provided.
In either embodiment, the ribs (18 or 48) are on the front of the implant, so that ~he legs are attached on the front of the implant. This not only facilitates release of the legs from the slots after the implant has be~n inserted into the eye, but also insures ~hat the implant will not be inserted into the eye backwards, that is, with the rear lens surface facing o~twardly, as has been kncwn to occur.
Although in the illustrated embodiment of the invention, means is provided for attaching each leg to the lens body, it will be understood that in some cases, provision may be made for attaching only one leg. I
For example in using an implant as illustrated in Figures 1-5, the surgeon may find it necessary to attach only one leg to the body before inserting the implant. Therefore the device of Figures 1-5 may, for certain applications, may have provision for attaching only one leg to the body.
Similarly in the embodiment of Figures 7 and 8, it may be necessary to make provision for attaching only one or two of the legs to the body. I
The means for attaching the leg to the body ha~s been illustrated as an enlarged end on the leg, and a slot in the peripheral rib to receive the end of the leg. It will be understood that other means for attaching the leg to the body may be provided without departing from the scope of the invention.

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Although in the illustrated embcdiments of the invention the implant is formed of a single piece of material, if desired, the resiiient legs may be formed separately and attached to the lens body by any suitable means.
Since certain o~her changes apparent to one skilled in the art may be made in the illustrated emkc~iments of the invention, it is intended that all matter contained herein be interpreted in an illustrative and not in a limiting sense.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An intraocular implant, comprising a lens body and a lens body retaining means comprising at least one flexible retaining leg which, in its un-restrained condition extends from a root portion joined to the lens body and terminates in a free end, said free end having a shoulder facing away from said end, and said lens body having latch means for receiving the shoulder in releasable latching engagement, said latching means being so positioned circumferentially that when the shoulder is retained by the latching means, the remainder of the leg lies around the periphery of the lens body.

2. An implant as set out in claim 1 in which three resilient legs are provided substantially equally spaced around the periphery of the lens body, and latch means is provided on the lens body for latching and releasably retaining the end of at least one of said legs, said latch means being so positioned circumferentially that substantially all of a leg retained by its latching means lies inside a circle having the center of the lens as a center and a diameter no greater than the diameter of the lens body.

3. An implant as set out in claim 1 in which the end of said leg has a laterally enlarged portion which forms said shoulder, and said lens body has an upstanding rib at the periphery, said rib having a transverse slot positioned to receive the portion of the leg adjacent to the enlarged portion so that said enlarged portion is held on the inside of the rib in releasable locking engagement.

4. An implant as set out in claim 1 in which said leg is integral with the lens body and has a proximal portion which is tapered from the root portion to a narrower medial portion, and a distal portion of substantially constant width beyond said medial portion, whereby stress in the leg caused by movement of the distal portion is distributed along the proximal portion.

5. An implant as set out in claim 3 in which said leg, in its un-restrained condition, is inclined at a slight angle to a plane through the lens perpendicular to the axis thereof, and the inside surface of the rib adjacent to the slot is disposed at an angle to said plane such that it is parallel to the shoulder portion of the leg.

6. An implant as set out in claim 3 in which said rib is so positioned on the peripheral portion that when the leg is flexed inwardly for engagement with the rib, the leg bears against the outside surface of the rib to control the curvature thereof.

7. An intraocular implant, comprising a lens body having a center lens portion and a peripheral lens support portion, and lens body retaining means comprising at least one resilient leg which, in the un-restrained condition extends generally tangentially from the peripheral support portion and spirals radially outwardly to an end portion which is turned inwardly and has a latching shoulder disposed thereon, and means on the lens body for receiving said latching shoulder to retain the inwardly turned end portion in engagement therewith.

8. An implant as set out in claim 7 in which said latching means comprises a rib and a slot extending generally transversely through the rib, said slot being dimensioned and positioned to receive the inwardly turned end portion when the leg is flexed around the peripheral portion and retain the leg in the flexed condition, substatially all of said leg, when so engaged with the rib, lying inside the outer circumference of the peripheral portion.

9. An implant as set out in claim 8 in which a rib portion is so positioned on the peripheral portion that the leg bears against the outer surface of the rib when the leg is flexed inwardly to the latched position.

10. An intraocular implant, comprising a lens body and lens body retaining means comprising at least one flexible retaining leg which, in its unrestrained condition, extends from a root portion attached to the lens body to a distal portion spaced from the body and terminating in a free end, said distal portion and said lens body having cooperating means to enable the distal portion to be releasably attached to the lens body.

11. An implant as set out in claim 10, in which the cooperating means comprises a portion disposed on the free end of the leg and a portion on the body so positioned that when the free end of the leg is attached thereto, the leg is flexed around the periphery of the body.

12. An intraocular implant, comprising a lens body and a lens body retaining means comprising at least one flexible retaining leg which, in its unrestrained condition extends from a root portion attached to the lens body to a distal portion spaced from the body and terminating in a free end, said distal portion and said lens body having cooperating means to enable the leg to be flexed circumferentially around the body and the distal portion attached to the body, and leg support means on the periphery of the body between the root portion of the leg and the free end thereof so positioned that when the leg is flexed around the body to enable the distal portion to be attached thereto, the leg bears against said leg support means to thereby control the amount of bending of said leg and to distribute the bending stress throughout a substantial portion of the leg and pre-vent excessive bending of the leg at the root thereof.

13. An implant as set out in claim 12, in which said leg support means comprises a peripheral wall extending circumferentially around a portion of the lens body.

14. An intraocular implant, comprising a lens body and at least one flexible retaining leg joined at the end to the lens body and in its unrestrained condition extends from the lens body and terminates in a free end, in which the free end of said leg has a laterally enlarged portion which forms a shoulder, and said lens body has upwardly projecting means at the periphery, said upstanding means forming a transverse slot positioned to receive the portion of the leg adjacent to the enlarged portion so that said enlarged portion is held between said upstanding portions in releasable locking engagement.

15. An implant as set out in claim 14, in which the leg is integrally formed with the lens body and has a proxi-mal portion which is tapered from the junction with the body to a narrower medial portion, and a distal portion of substantially constant width beyond said medial portion, whereby stress in the leg caused by movement of the distal portion is distributed along the proximal portion and is not concentrated at said junction.