WO2013016804A1

WO2013016804A1 - Negatively pressurized deformable lens

Info

Publication number: WO2013016804A1
Application number: PCT/CA2012/000716
Authority: WO
Inventors: Garth T. Webb
Original assignee: Webb Garth T
Priority date: 2011-08-03
Filing date: 2012-07-27
Publication date: 2013-02-07

Abstract

A sealed fluid-filled lens is provided which comprises an internal lens compartment that is subject to negative partial pressure. It has an elastically deformable liquid-impermeable surface membrane, forming a hollow interior chamber filled with a refractive fluid. Internal structural elements interact with the surface membrane to cause change of curvature of the lens when the sealed fluid-filled lens is engaged by either intrinsic or extrinsic force.

Description

Negatively Pressurized Deformable Lens

Reference to Related Application

[0001] The present application claims the benefits, under 35

U.S.C.§ 119(e), of U.S. Provisional Application Serial No. 61/514,746 filed August 3, 2011 which is pending and is incorporated herein by this reference. The present invention relates to the applicant's inflatable lens/ lens retainer as disclosed in United States patent application no. 12/671,573 entitled INFLATABLE INTRA OCULAR LENS / LENS RETAINER filed August 12, 2008, which is pending, and which is incorporated herein in its entirety.

Technical Field

[0002] The invention relates to the field of refractive interfaces, in particular optical lenses and intraocular lens implants.

Background

[0003] Many attempts to regulate curvature change of refractive interfaces have been recorded, especially in the area of intraocular lens implants. Examples are disclosed in Feaster WO 9011736, Pynson

CA2630781 and Shadduck WO 2008024766.

[0004] Thin optical interfaces made of elastic materials can change shape in response to hydraulic pressure; however, curvature change thus achieved is bi-phasic and of poor optical quality. Other problems, such as material fatigue and material stability also arise with such interfaces. Thin optical interfaces composed of flexible materials with good shape memory properties do not easily change curvature. [0005] United States patent application no. 12/671,573 discloses control mechanisms which regulate curvature change (Optical spring' and 'grooved optical interface'); however, there remains a need for

improvement to broaden the scope of application for curvature modulated lens designs. [0006] The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

Summary

[0007] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements. [0008] A sealed fluid-filled lens is provided which comprises an internal lens compartment that is subject to negative partial pressure; while at rest, further comprising internal structural elements which regulate shape change when the sealed fluid-filled lens is engaged by either intrinsic or extrinsic force. While the present invention has particular application as an improvement in flexible optical interfaces and support structures of the type shown in United States patent application no. 12/671,573, it also has more general application to cameras and other optical equipment.

[0009] The invention therefore provides a sealed fluid-filled lens, comprising: i) a flexible deformable liquid-impermeable membrane, forming a hollow interior chamber filled with a refractive fluid, and comprising a central transparent optical zone; and ii) a flexible internal structural element which bears against the inner surface of the flexible deformable liquid-impermeable membrane to thereby modify the curvature of the deformable liquid-impermeable membrane when the sealed fluid- filled lens is engaged by extrinsic or intrinsic force, wherein the hollow interior chamber is maintained at a negative partial pressure relative to the exterior of the lens [0010] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed

descriptions.

Brief Description of Drawings

[0011] Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.

[0012] Fig. 1 is a cross-sectional view of annular inflatable intraocular retainers positioned within the intra-capsular space of a human eye.

[0013] Fig. 2 is a perspective view of an inflatable lens according to the invention;

[0014] Fig. 3 is a cross-section along lines 3-3 of Fig. 2 showing the invention in distended configuration with maximum negative partial pressure.

[0015] Fig. 4 is a cross-section along lines 3-3 of Fig. 2 showing the invention in extended configuration with reduced negative partial pressure.

Description

[0016] Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure.

Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

[0017] Fig. 1 illustrates the structure disclosed in United States patent application no. 12/671,573 where annular inflatable intraocular retainer 26 is positioned within the intra-capsular space, directly in front of posterior lens capsule 14 and annular inflatable intraocular retainer 28 is positioned behind anterior lens capsule 12. Liquid is introduced into inflatable intraocular retainer 26 through filling port 30. Liquid is introduced into inflatable intraocular retainer 28 through filling port 32. Lens compartment 34 is defined as the space between posterior lens support 36 and anterior lens support 38. Posterior lens support 36 is a diaphragm that stretches across the front surface of inflatable intraocular retainer 26 and anterior lens support 38 is an annular diaphragm that stretches across the front surface of inflatable intraocular retainer 28. These 'doughnut' shaped inflatable intraocular retainers 26, 28 are pressed directly against the mid-peripheral zones of the walls of the lens capsule once a compatible accommodative or a pseudo-accommodative intraocular implant is installed. Zonular tension compresses the intra- capsular space and pushes the lens capsule retainers 26, 28 toward each other. The depth A of lens compartment 34 varies as the zonular tension changes, thereby actuating compatible intraocular lens implants. The present invention is an improved accommodative implant for insertion in lens compartment 34.

[0018] Fig. 2 through 4 illustrate a sealed fluid-filled lens 40, lens 40 being a symmetric circular disc sized for insertion in lens compartment 34. It is covered in a transparent, liquid-impervious, sealed, flexible film or membrane 42, also referred to herein as the flexible optical interface, which forms an interior volume 46 containing a refractive fluid medium 44.

Preferably, but optionally, flexible optical interface 42 is stretchable and elastic, in that it returns to its original shape after being deformed. Flexible optical interface 42 may be constructed of silicone rubber, silicone hydrogel materials, polyethylene or polyurethane. Refractive fluid medium 44 is preferably a refractive liquid, such as silicone oil, although the term "liquid" could also include glycerine, silicone gel or gas. Gasses used as refractive fluid medium 44 should be relatively inert, physiologically compatible and preferably of large molecular weight, such as methane or the gasses used for reparative retinal surgery, available from Alcon Laboratories Inc under the trademark Ispan C3F8 for medical grade perflurocarbon gas and Ispan SG6 for medical grade sulfurhexafloride gas. Air may also be used.

[0019] The interior volume 46 of lens 40 forms an internal lens compartment that is subject to negative partial pressure in order to maintain the film or membrane 42 in tight relationship to the internal structure of the lens 40. The internal lens compartment further comprises internal structural elements 48, 50 which regulate shape change when the sealed fluid-filled lens is engaged by either intrinsic or extrinsic force. Transparent rigid disk 48 has a curved surface 52 which bears tightly against film 42. It has a lower generally planar surface 54 which bears against a transparent flexible hemi-spherical shell 50. Shell 50 is made of a spring-like flexible material such as a suitable transparent plastic, which is provided with slots 56 along the longitudinal meridians of the hemispherical shell 50. Slots 56 extend completely though shell 50 to permit fluid 44 to flow between the interior and the exterior of shell 50, so that the interior of shell 50 is always filled with the refractive liquid medium 44. This shell 50 can collapse to the extended configuration shown in Fig. 4 when subject to external force such as hydraulic pressure and mechanical compression or expand to the distended position shown in Fig. 3, to produce optically cohesive curvature change. An intrinsic force which changes the shape of the lens may be hydraulic force applied from outside of the lens using connective tubing connecting a source of hydraulic pressure to the interior volume 46. [0020] The habitual volume of space within the disclosed sealed inflatable lens compartment 46 is defined by the habitual shape of the internal supportive structure 48, 50 and the resiliency of the walls 42 of the sealed inflatable lens 40. When the habitual volume is greater than the volume of liquid medium contained therein, a negative partial pressure pervades within the lens compartment 46. It has been found that negative partial pressure within the sealed lens compartment 40 enhances the efficiency of curvature change and with this, provides more versatile lens design options. [0021] The internal supportive structure may be constructed as independent elements 48, 50 positioned within the sealed lens compartment or it may be integrated within or upon a wall of the sealed lens

compartment. The internal supportive structure is shaped and positioned within the sealed lens compartment so that it presses against the inner surface of the flexible optical interface 42.

[0022] In some embodiments, peripheral regions of the flexible optical interface 42 remain free to flex and change shape in response to hydraulic pressure. In others, central regions of the flexible optical interface remain free to flex and change shape.

[0023] In some embodiments the internal supportive structure 48, 50 may be deformable. In some embodiments, it may be a rigid structure that is pressed against a second flexible optical interface simultaneously with the first flexible optical interface. There are many variations to the shape of the collapsible supportive structure 48, 50 as it is invisible while it is immersed within an index-matched fluid 44.

[0024] Similarly, there are many variations to the shape of the sursaces of the flexible optical interface 42. They may be grooved for maximum range and cohesiveness of curvature change, or not. They may be smooth or irregular. The flexible optical interface 42 may contain fortified structural elements within its walls, or not. It may have well defined optical zones, or not. Variables such as these may be considered for specific applications but they are not critical to the fundamental operation of a negatively pressurized sealed fluid-filled lens. [0025] Negative partial pressure within the sealed lens compartment 40 draws the flexible optical interface 42 against the internal supportive structure 48, 50. Peripheral and mid-peripheral regions of a flexible optical interface 42 may be configured to flex inwardly, thereby generating greater convexity. Alternatively, central regions of a flexible optical interface 42 may be configured to flex inwardly, thereby generating reduced convexity.

[0026] In operation, mechanical compression of the negatively pressurized sealed fluid-filled lens collapses the internal supportive structure 48, 50. Refractive fluid is displaced from the interior of shell 50 to its exterior. This displaced refractive fluid allows flexible optical interface 42 to return to its habitual shape when the negative internal pressure reduced as shown in Fig 3.

[0027] Hydraulic pressure upon the surface of a flexible optical interface of a negatively pressurized sealed fluid- filled lens creates slightly different dynamics than does mechanical compression. The shape of flexible optical interface 42 conforms to the shape of shell 50. As shell 50 collapses in response to hydraulic pressure, flexible optical interface 42 remains in juxtaposition with the surface of shell 50. Displaced fluid from the interior of shell 50 is channelled through slots 56 which perforate supportive structure 50 to lift portions of the flexible optical interface 42 in juxtaposition with it.

[0028] The diameter of the flexible optical interface 42 of a sealed fluid-filled lens 10 may reduce in unison with negative pressurization. Radial traction upon peripheral regions of a negatively pressurized flexible optical interface 42 may be utilized to compress the internal lens compartment 40 to impart curvature change.

[0029] While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the invention be interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope. While the present invention has particular application as an improvement in flexible optical interfaces and support structures, it will be apparent that it also has more general application to cameras and other optical equipment wherein the extrinsic or intrinsic force applied to the lens is provided by the focusing mechanism of a camera, telepscope, binoculars, projector or other optical systems.

Claims

WHAT IS CLAIMED IS:

1. A sealed fluid-filled lens, comprising:

i) a flexible deformable liquid-impermeable membrane, forming a hollow interior chamber filled with a refractive fluid, and comprising a central transparent optical zone; and ii) a flexible internal structural element which bears against the inner surface of said flexible deformable liquid- impermeable membrane to thereby modify the curvature of said flexible deformable liquid-impermeable membrane when the sealed fluid-filled lens is engaged by extrinsic or intrinsic force. wherein said hollow interior chamber is maintained at a negative partial pressure relative to the exterior of said lens.

2. The sealed fluid-filled lens of claim 1 wherein said flexible deformable liquid-impermeable membrane is elastic.

3. The sealed fluid-filled lens of claim 2 wherein said flexible deformable liquid-impermeable membrane is stretchable.

4. The sealed fluid-filled lens of claim 1 wherein said refractive fluid is transparent.

5. The sealed fluid-filled lens of claim 1 which is sized and configured for implantation into the intra-capsular space of the lens capsule of an aphakic eye.

6. The sealed fluid- filled lens of claim 1 wherein said deformable liquid- impermeable membrane is formed from a material selected from the group consisting of silicone rubber, silicone hydrogel materials, polyethylene and polyurethanes.

7. The sealed fluid-filled lens of claim 1 wherein said fluid is selected from the group consisting of glycerine, silicone oil and silicone gel.

8. The sealed fluid- filled lens of claim 1 wherein said fluid is a gas.

9. The sealed fluid-filled lens of claim 8 wherein said gas is a gas of large molecular weight.

10. The sealed fluid-filled lens of claim 8 wherein said gas is air.

11. The sealed fluid-filled lens of claim 9 wherein said gas is selected from the group consisting of methane, perflurocarbon gas and sulfurhexafloride gas.

12. The sealed fluid-filled lens of claim 1 wherein said internal structural element comprises a transparent, flexible hemi- spherical shell having a surface which bears against the inner surface of said membrane.

13. The sealed fluid- filled lens of claim 1 wherein said internal structural element further comprises a transparent rigid disc which bears against an inner surface of said membrane and interacts with said flexible hemispherical shell when extrinsic force is applied to said lens.

14. The sealed fluid- filled lens of claim 1 wherein said flexible hemispherical shell is provided with passageways to permit the flow of said refractive fluid from the interior to the exterior of said flexible hemispherical shell.

15. The sealed fluid-filled lens of claim 1 wherein said flexible hemispherical shell is biased to an extended position causing a maximum curvature of said membrane and whereby application of an external compressive force to said lens causes said flexible hemi- spherical shell to collapse to a position causing a minimum curvature of said membrane.

16. The sealed fluid-filled lens of claim 1 wherein said extrinsic force is hydraulic pressure or mechanical compression applied to the exterior of said lens.

17. The sealed fluid-filled lens of claim 1 wherein said extrinsic force is hydraulic pressure provided to the interior of said lens from an exterior source.

18. An intraocular lens system for implantation into an aphakic eye, comprising the sealed fluid- filled lens of claim 1.

19. A method of providing improved accommodation from an intraocular lens implanted into an aphakic eye, said method comprising providing the sealed fluid-filled lens of claim 1 within an implanted lens accommodating structure.

20. The method of claim 19 wherein said implanted lens accommodating structure comprises an inflatable intraocular lens retainer.