Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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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
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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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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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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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~ 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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