Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Eye prosthesis – Intraocular lens
Reexamination Certificate
1998-10-05
2001-05-29
Willse, David H. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Eye prosthesis
Intraocular lens
C623S006430
Reexamination Certificate
active
06238433
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to intraocular lenses (IOL's) and in particular to IOL's that reduce or even eliminate irritation of the ciliary band in the eye and reduce the incidence of papillary block, and, if a natural crystalline lens is present, to reduce the risk of cataract formation.
IOL's are commonly used to modify vision. For example, IOL's are used to replace the natural lens of the eye when warranted by medical conditions. A common practice is to implant an IOL in a region of the eye known as the capsular bag or posterior capsule. However, in this practice, cells from the eye tend to grow on the capsular bag in front of and/or in back of the optical portion of the IOL. This tends to block the optical portion of the IOL and impair vision.
IOL's may be implanted in regions of the eye other than in the capsular bag. Referring now to Prior Art
FIG. 1
, an anterior IOL (AIOL)
10
is shown implanted in an eye
12
. The eye
12
is comprised of a cornea
14
shown to the left and an iris
16
shown in the middle of the eye. It is to be understood that the cornea
14
is at the front of the eye
12
. The iris
16
divides the eye
12
into an anterior chamber
18
at the front of the eye and a posterior chamber
20
in back of the iris. The iris
16
also defines the pupil
22
, which is an opening in the middle of the iris. In front of the iris
16
is the scleral spur
24
. The scleral spur
24
and the iris
18
delimit the ciliary band
26
. Behind the iris
16
is the ciliary process
28
, from which extends the ciliary muscle
30
. The ciliary muscle supports the natural crystalline lens
32
of the eye
12
. The iris
16
and the ciliary process
28
define the sulcus
34
.
Prior Art
FIG. 1
shows the AIOL
10
implanted in the anterior chamber
18
of the eye
12
. The AIOL
10
is comprised of an optic
40
that is supported in front of the pupil
22
by loops or haptics
42
. The optic
40
, for the AIOL
10
and other IOL's described herein, may be considered as including an optical portion for focusing light at or near the retina (not shown) of the eye
12
. The haptics
42
extend from the optic
40
and rest in the ciliary band
26
. The haptics
42
are designed to minimize compression stress on the optic
40
and inhibit forward vaulting of the optic. If the optic
40
vaults and contacts the cornea
14
, an undesirable condition known as endothelium tough may occur. However, this condition may occur from the haptics
42
merely residing in the ciliary band
26
.
Referring now to Prior Art
FIG. 2
, the eye
12
now has a posterior IOL (PIOL)
50
implanted therein. The PIOL
50
is comprised of an optic
52
that is supported behind the pupil
22
by loops or haptics
54
. The haptics
54
extend from the optic
52
and rest against the sulcus
34
. In terms of inhibiting endothelium tough, the PIOL
50
is superior to the AIOL
10
as the opportunity for any part of the PIOL to contact the cornea
14
is greatly reduced. However, the PIOL
50
has increased opportunity for contacting the natural crystalline lens
32
due to their proximity. Having any object contact the lens
32
is undesirable as it may result in the incidence of papillary block and cataract formation.
It would be advantageous to provide an intraocular lens that reduces, or even minimizes, both the risks of endothelium tough and of papillary block.
SUMMARY OF THE INVENTION
Posterior/anterior chamber intraocular lenses (PACLS) for implantation in an eye have been discovered. The present PACLs have an optic and at least one elongated fixation member, preferably two elongated fixation members. The optic has an optical axis. The fixation member has a proximal segment joined to the optic, a distal segment, for example, extending away from the optic, and an intermediate segment joining the proximal and distal segments. The optic is adapted to be positioned in the anterior chamber, that is anterior of the iris, of the eye, while the distal segment of the fixation member is adapted to be positioned in the posterior chamber, that is posterior of the iris, of the eye. The optic is, thus, spaced apart from the natural crystalline lens of the eye, if such lens is present, and reduces the risk of cataract formation in the natural lens and papillary block. The fixation member, that is the distal segment of the fixation member, being positioned in the posterior chamber reduces the risk of endothelium tough and effectively fixates or fixes the PACL in the eye.
In one embodiment, the intermediate segment of the fixation member has a through-iris portion adapted to extend through the iris of the eye in which the PACL is implanted. For example, a hole may be provided which extends through the iris. The through-iris portion is adapted to extend through the hole. The hole may be an iridectomy opening. The through-iris portion of the fixation member preferably has a longitudinal axis oriented in a direction other than normal to the optical axis. More preferably, the through-iris portion extends generally parallel to the optical axis of the optic.
The through-iris portion may comprise two ends defining a line that is not normal to the optical axis. The line may be generally parallel to the optical axis.
In one embodiment of the invention, the fixation member defines an arc with a discontinuity, preferably at the intermediate segment. The discontinuity preferably extends generally parallel to the optical axis. The arc may extend generally tangentially away from the optic.
The proximal segment of the fixation member preferably is adapted to be disposed in the anterior chamber. This arrangement inhibits the optic from contacting the natural lens of the eye, which can result in papillary block and cataract formation. The distal segment is adapted to be disposed in the posterior chamber of the eye. This arrangement inhibits the distal segment from contacting the cornea and causing endothelium tough. In one very useful embodiment, the distal segment of the fixation member is adapted to be more flexible than the proximal segment or intermediate segment. For example, the distal segment can be made of a more flexible material of construction and/or can have a reduced cross-sectional area relative to one or more of the other segments of the fixation member. Having a fixation member with a relatively more flexible distal segment tends to reduce the movement of the intermediate segment through the iris. Such reduced movement advantageously results in reduced irritation of the iris.
Another aspect of the invention is directed to methods for implanting an intraocular lens in an eye. These methods comprise providing an intraocular lens having a optic and an elongated fixation member which includes a proximal segment joined to the optic, a distal segment, and an intermediate segment joining the proximal and distal segments. The methods include positioning the optic in the anterior chamber of the eye, and positioning the distal segment of the fixation member in the posterior chamber of the eye. The distal segment positioning step includes placing the distal segment against the sulcus of the eye. The positioning of the distal segment may include directing the distal segment through a hole extending through the iris to dispose the intermediate segment of the fixation member in the iris hole. The directing may include rotating the intraocular lens about the optical axis such that the distal segment of the fixation member moves through the iris hole until the intermediate segment is disposed in the iris hole. In one embodiment, the method further comprises performing an iridectomy to form the iris hole.
The iris hole in which the intermediate segment of the fixation member is located may be enlarged relative to a conventional iridectomy hole, which is often on the order of about 0.5 mm in size. For example, the iris hole may be enlarged before or after disposing the intermediate segment in the iris hole. This feature reduces the risk of eye irritation and enhances beneficial
Allergan Sales Inc.
Uxa Frank J.
Willse David H.
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