GB2084024A

GB2084024A - Intraocular implant unit

Info

Publication number: GB2084024A
Application number: GB8119316A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-09-19
Filing date: 1981-06-23
Publication date: 1982-04-07
Also published as: JPS5755142A; DE3116270A1; FR2490484A1; BE888392A; NL8102844A

Abstract

An intraocular implant unit (10) having a lens (12) with a limb (14) integral with or attached to the lens (12) and extending outward radially from a first margin portion of the lens (12). An arcuate rim (16) is centered on the end of the limb (14) and at least one flexible strand (18) is rooted in a second margin portion of the lens (12) having a free curved end whose curvature is centered on the axis (10a) of the limb (14). <IMAGE>

Description

SPECIFICATION Intraocular implant unit This invention relates to an intraocular implant unit. The unit, which may incorporate a lightweight lens, is intended for implantation in the posterior chamber of an eye following extracapsular surgery.

Lens implants on patients who undergo surgery because of the presence of cataracts are widely practiced. Developments leading to acceptance of the technique and of lenses designed for implant are discussed in "A Lens For All Seasons by Jerald L.

Tennant, 1976. The developments of lenses by Dr.

Peter Choyce, by Applicant and others have led to wide acceptance with many hundreds of implants being performed using such lenses. In such systems, the lens is placed in the anterior chamber of the eye.

Fixation of the lens is assured, for example, by four point contacts made by feet extending from the lens proper.

In some instances, however, it has been found to be desirable to provide an implant in the posterior chamber of the eye following extracapsular surgery involving removal of the natural lens, while leaving intact the posterior capsule. Thus, the present invention seeks to provide a lens unit suitable for implant in the posterior chamber with minimal tissue loading, having ease of centering and positive fixation while being convenient for insertion through the pupil.

The present invention provides an intraocular implant unit comprising a lens; a lens supporting member extending radially outwardly from a periphery of the lens, said supporting member having a first arcuate portion centrally supported by a limb portion, said limb portion being fixed to a peripheral portion of the lens and extending between said peripheral portion and said first arcuate portion; and a flexible strand fixed to a peripheral portion of the lens and having a second arcuate portion disposed substantially opposite said first arcuate portion.

A lens implant unit embodying the invention has a lens body which is sized to pass through the pupil of the eye, whereafter the first and second arcuate portions may be based in opposed portions of the ciliary sulcus to support the lens body in alignment with the pupil. An advantage of such unit is that the first arcuate portion of the lens supporting member will centre without the need for additional fixation.

Embodiments of the invention will now be described with reference to the accompanying draw ings, in which: FIGURE 1 is a front view of a posterior chamber lens according to one embodiment of the invention; FIGURE 2 illustrates the lens of FIGURE 1 mounted in the posterior chamber of an eye; FIGURE 3 is a front view of a modification of the lens of FIGURE 1; and FIGURE 4 is a front view of a modification of the lens of FIGURE 1.

Referring to Figure 1, an intraocular implant lens according to an embodiment of the present invention is illustrated and is generally identified by the numeral 10. Lens 10 includes a lens optic 12 of piano-convex shape which is formed integrally with a six-o'clock substantially rigid limb 14. Limb 14 extends diametrically from one edge of lens optic 12.

An arcuate rim segment 16 is integral with and centred on the end of limb 14 opposite optic 12. Rim segment 16 spans an arc of about 6 to 8 millimeters and is of generally the same thickness and width of limb 14, about 1.2 millimeters. Rim segment 16 lies in the plane perpendicular to an axis 10a of lens 10 and limb 14 and presents a curved outer surface 16a which is preferably rounded on the edges and smoothed to provide contact over the entire length of the surface 16a with the ciliary sulcus in the posterior chamber of an eye into which lens 10 is to be implanted.

Integrally formed with or secured to optic 12 of lens 10 is a flexible support strand 18. Strand 18 may be of the type disclosed in U.S. Patent No.4.159,546 to Shearing. Support strand 18 is located to contact the ciliary sulcus at the 12-o'clock position and is secured to optic 12 in about the 3-o'clock position.

In a typical embodiment, optic 12 would have a diameter of approximately 4 to 6 millimeters. The chord length or rim segment 16 would be approximately 6 to 8 millimeters as would the diameter of the loop end of support strand 18. Typically, the radius of the outer surface 16a of rim segment 16 measured from the center of optic 12 would be of the order of about 6 to 7 millimeters as would be the distance from the center of optic 12 to strand 18 measured along axis 10a, such that the distance between strand 18 and the outer surface 16a of rim 16 approximates the diameter of the posterior chamber of an eye.

The lens 10 as illustrated in FIGURE 1 provides fixation which prevents rotation of optic 12 within the eye of a patient. Previously developed posterior chamber implant lenses, such as the above referred Shearing lens, and other posterior chamber lenses such as, for example. Pearce, Harris and Simcoe, all suffer from decentration because the flexible inferior loop of these lenses may allow superior or inferior decentration of the optic. In these previously developed lenses, the lack of horizontal support allows horizontal decentration. Lens 10 of the present invention, however, utilizing the fixed length of limb 14 dictates vertical centration of optic 12. The arcuate rim segment 16 prevents horizontal displacement while spreading the weight of lens 10 over a large weight-bearing surface.Support strand 18 being flexible allows lens 10 to be placed through the pupil of an eye and maintains the desired location in the eye until fibrous fixation occurs within the posterior chamber of an eye. Limb 14 further prevents torsion of lens 10 with capture of optic 12 by the pupil.

By providing limb 14 and support strand 18 with anterior inclination and by providing rim segment 16 and support strand 18 with circumferential extension, clearance of the iris is provided to avoid rubbing the iris tissue. Alternatively, support strand 18, limb 14 and rim segment 16 may lie coplanar with optic 12.

Disposed at the 12-o'clock , 3-o'clock and 9-o'clock positions of optic 12 and along axis 1 Oa within rim segment 16 are apertures 19. Apertures 19 can be utilized by the surgeon with a suitable instrument to center and position lens 10 during implantation.

Optic 12 shown in FIGURE 1 may be of a planoconvex configuration, convex-plane or biconvex.

However, the convex-plano configuration is preferred inasmuch as it provides maximum spacing between the iris and the anterior surface of optic 12.

irritation in the postoperative period of the raw edges of the iris is thus avoided.

Referring to FIGURE 2, the lens 10 is shown in position in an eyeball 20. Eyeball 20 includes a cornea 22 and an iris 24 having a central opening or pupil 26. Iris 24 divides eyeball 20 into an anterior chamber 28 and a posterior chamber 30. Lens 10 is shown in position in posterior chamber 30 of eyeball 20 such that rim segment 16 lies adjacent the ciliary sulcus 32 for fibrous fixation within posterior chamber 30. Also illustrated in FIGURE 2 is the remnant of anterior capsule 34 of posterior chamber 30 and posterior capsule 36.

The vectors of weight directed in the 6-o'clock position of lens 10 causes optic 12 of lens 10 to remain centered within posterior chamber 30. Curved surface 16a of rim segment 16 of lens 10 may be manipulated to guide easily into ciliary sulcus 32 without a tendency to penetrate posterior capsule 36. Thus, lens 10 of this embodiment will fixate and center without the need for additional fixation.

It is understood that preparatory to implanting lens 10 through pupil 26, an opening is made into anterior capsule 34 for fragmentation and removal of the lens being replaced.

Optic 12, limb 14, rim segment 16 and support strand 18 are all made of material suitable for eye implant. Such material may be of the nature of polymethylmethacrylate (PMMA). In accordance with the principles described in US Patent No.

4254509; for example, optic 12 and rim segment 16 may be of rigid material, such as polymethylmethacrylate (PMMA), while limb 14 may be of a softer material of the nature of hydrogels, e.g. a soft hydrogel of the hydrophylic type such as 2-hydroxyethyl methacrylate (PHEMA); alternatively limb 14 may be composed of PMMA. Support strand 18 may be composed of extruded PMMA and similar materials, or polypropylene and similar materials.

Thus, from the foregoing it will be seen that intraocular implant lens 10 is provided, comprising an optic 12 with a 12-o'clock support strand 18 and a narrow 6-o'clock limb 14 supporting rim segment 16.

Arcuate rim segment 16 has its center of curvature at the center of optic 12 and is disposed from the center of optic 12 about one-half the diameter of the posterior chamber 30 in which lens 10 isto be implanted.

The overall length of lens 10 approximates the diameter of posterior chamber 30.

Referring now to FIGURE 3, a modification of intraocular implant lens 10 is illustrated and is generally identified by the numeral 40. Lens 40 includes optic 12, limb 14 and rim segment 16 as previously described. Lens 40 includes support strand 18 arid a second support strand 18a interconnected to optic 12 in approximately the 9-o'clock positior. Support strands 18 and 18a are of the same shape and each have the same relationship to axis 1 0a of lens 40 and to limb 14. By providing flexible support strands 18 and 18a of opposite curvatures and mounting them symmetrical to axis 1 Oa, forces which tend to cause lens 40 to rotate are compensated and even greater stability is provided to intraocular implant lens 40.

Referring now to FIGURE 4, wherein like numerals are utilized for like and corresponding components previously identified, a further modification of intraocular implant lens 10 is illustrated and is generally identified by the numeral 50. Lens 50 includes optic 12 and support strand 18 as previously described with reference to FIGURE 1. Substituted for limb 14 and rim segment 16, which are integral with optic 12 of lens 10 is a continuous loop 52 in the same general shape of limb 14 and rim segment 16 of lens 10.

Loop 52 may be composed of extruded PMMA and similar materials, or polypropylene and similar materials, and is rootedto optic 12 in approximatelythe 6-o'clock position.

Having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest themselves to those skilled in the art, and it is intended to cover such modifications as fall within the scope of the appended claims.

Claims

1. An intraocular implant unit comprising a lens; a lens supporting member extending radially outwardly from a periphery of the lens, said supporting member having a first arcuate portion centrally supported by a limb portion, said limb portion being fixed to a peripheral portion of the lens and extending between said peripheral portion and said first arcuate portion; and a flexible strand fixed to a peripheral portion of the lens and having a second arcuate portion disposed substantially opposite said first arcuate portion.

2. A unit according to claim 1, wherein said first and second arcuate portions lie in a plane which is displaced from the plane of said lens.

3. A unit according to claim 1, wherein said first and second arcuate portions lie in a plane which is coplanar with the plane of said lens.

4. A unit according to any one of claims 1-3, wherein said lens, said first arcuate portion, and said flexible strand are made of substantially rigid material and said limb portion is made of softer material.

5. A unit according to claim 1 or 2, wherein said lens, said lens supporting member and said flexible strand are made substantially of rigid material.

6. A unit according to claim 4 or 5, wherein said rigid material is polymethylmethacrylate.

7. A unit according to claim 4 or 6, wherein said softer material is polypropylene. -

8. A unit according to any one of the preceding claims, wherein said lens is a plano-convex lens.

9. A unit according to any one of the preceding claims, wherein said lens includes apertures which are circumferentially disposed about its periphery.

10. A unit according to any one of the preceding claims, wherein the peripheral portion of the lens to which said flexible strand is fixed is circumferentially spaced by substantially 90"from the peripheral por tion of the lens to which said limb portion is fixed.

11. A unit according to any one of the preceding claims, wherein a second flexible strand is attached toe peripheral portion of the lens, said second strand having a third arcuate portion disposed substantially opposite to said first arcuate portion.

12. A unit according to claim 11, wherein the peripheral portion of the lens to which said second strand is fixed is circumferentially spaced by substantially 90 from the peripheral portion oFthe lens to which said limb portion is fixed and wherein the peripheral portions of the lens to which said firstmentioned strand and said second strands are respectively fixed are substantially diametrically opposite one another.

13. A unit according to any one of the preceding claims, wherein said limb portion and said arcuate portion of said lens supporting member are of an integral construction.

14. A unit according to any one Of he preceding claims, wherein said limb portion and said arcuate portion cf said lens supporting member are integral with one another and are formed by a filament configured into a loop.

15. The intraocular implant lens of Claim 11 wherein said first flexible strand is rooted in the three-o'clock position tangent of said central lens and said second flexible strand is rooted in the nine-o'clock position tangent of said central lens.

15. A unit according to any one of the preceding claims, wherein the arcu & e portion of the or each said supporting strand is centered on the Gongitudi- nal axis of said limb portion.

16. An intraccular implant unit substantially as herein described with reference to Fig 1 of the accompanying drawings.

17. Ain intraocular implant unit substantially as herein described with reference to Fig 2 of the accompanying drawings.

13. An intraocular implant unit substantially as herein described with reference to Fig 3 of the accompanying drawings.

i#ew claims or amendments to claims filed on 7th January 1982 superseded claims 1 to 15.

Msw or amended claims:~

1. An intraocular implant lens unit for installation and irnmobili2ation in a circularly bounded chamber in the eye of a patient comprising: a central lens; a substantially rigid limb e:'tending outxardly radially from a margin portion of said central lens; an arcuate rim portion centered on the end of said limb for engaging the lower ciliary sulcus of the eye for supporting and centering said central lens in the circular bounded chamber, said rim conforming to a.

circle having a diameter approximately scud to the diameter of the circularly bounded chamber; a flexible strand having a linear portion and an arcuate portion, each of said portions having first and second ends, said linear portion first end being rooted in the edge of said central lens, such that said linear portion extends tangentially of said central lens, said first end of said arcuate portion extending from said second end of said linear portion in a continuous unbroken curve, said second end of said arcuate portion being unsecured; and said arcuate portion of said flexible strand conforming to a circle centered on the axis of said limb and being disposed approximately opposite said arcuate rim portion for engaging the upper ciliary sulcus of the eye for stabilizing the central lens in the circular bounded chamber of the eye.

2. The intraocular implant lens of Claim 1 wherein said rigid limb, said arcuate rim portion and said flexible strand lie coplanar with said central lens.

3. The intraocular implant lens of Claim 1 wherein the contact plane of said arcuate rim portion and said arcuate portion of said flexible strand is antsriorto said central lens.

6% The intraocular implant lens of Claim 1 wherein said rigid limb is disposed in the six-o'clock position along the margin of said central lens.

5. The intraocular implant lens of Claim 1 wherein said flexible strand is rooted in the three- o clock position tangent of said central lens.

6. An intraocular implant lens unit for installation and immobilization in a circularly bounded chamber In the eye of a patient comprising: a central lens; a continuous loop extending outwardly radially from 3 margin portion of said central lens and having a limb portion and an arcuate rim portion cen .ered on the end of said limb for engaging the lower ciliary sulcus of the eye for supporting and centering said central lens in the circular bounded chamber, said arcuate rim portion conforming to a circle having a diameter approximately coucl to the diameter of the circularly bounded chamber;; 3 flexible strand having a linear portion and an arcuate portion, each of said portions having first and second ends, said linear portion first end being rooted in the edge of said central lens, such that said linear portion extends tangentially of said central lens, said first end of said arcuate portion extending from said second end of said linear portion in a con sinuous unbroken curve, said second end of said arcuate portion being unsecured; and said arcuate portion of said flexible strand conforming to a circle centered on the axis of said limb and being disposed approximately opposite said arcuate rim portion for engaging the upper ciliary sulcus of the eye for stabilizing the central lens in the circular bounded chamber of the eye.

7. The intraocular implant lens of Claim 6 wherein said continuous loop and said flexible strand lie coplanar with said central lens.

3. The intraocular implant lens of Claim 6 wherein the contact plane of said arcuate rim portion o; said continuous loop and said arcuate portion of said flexible strand is anterior to said central lens.

9. The intraocular implant lens of Claim 6 sherein said continuous loop is disposed in the six o clock position along the margin of said central lens.

10. The intraocular implant lens of Claim 6 wherein said flexible strand is rooted in the threeo'clock position tangent of said central lens.

11. An intraocular implant lens unit for installation and immobilization in a circularly bounded chamber in the eye of a patient comprising: a central lens; a substantially rigid limb extending outwardly radially from a margin portion of said central lens; an arcuate rim portion centered on the end of said limb for engaging the lower ciliary sulcus of the eye for supporting and centering said central lens in the circular bounded chamber, said rim conforming to a circle having a diameter approximately equal to the diameter of the circularly bounded chamber;; a first flexible strand having a linear portion and an arcuate portion, each of said portions having first and second ends, said linear portion first end being rooted in a first edge of said central lens, such that said linear portion extends tangentially of said central lens, said first end of said arcuate portion extend- ing from said second end of said linear portion in a continuous unbroken curve, said second end of said arcuate portion being unsecured; said arcuate portion of said first flexible strand conforming to a circle centered on the axis of said limb and being disposed approximately opposite said arcuate rim portion for engaging the upper ciliary sulcus of the eye for stabilizing the central lens in the circular bounded chamber of the eye;; a second flexible strand having a linear portion and an arcuate portion, each of said portions having first and second ends, said linear portion first end being rooted in a second edge of said central lens, such that said linear portion extends tangentially of said central lens, said first end of said arcuate portion extending from said second end of said linear portion in a continuous unbroken curve, said second end of said arcuate portion being unsecured; and said arcuate portion of said second flexible strand conforming to a circle centered on the axis of said limb and being disposed approximately opposite said arcuate rim portion for engaging the upper ciliary sulcus of the eye for stabilizing the central lens in the circular bounded chamber of the eye.

12. The intraocular implant lens of Claim 11 wherein said limb, said arcuate rim portion and said first and said second flexible strands lie coplanar with said central lens.

13. The intraocular implant lens of Claim 11 wherein the contact plane of said arcuate rim portion and said arcuate portion of said first and said second flexible strands is anterior to said central lens.

14. The intraocular implant lens of Claim 11 wherein said limb is disposed in the six-o'clock position along the margin of said lens.