CA2106809A1

CA2106809A1 - In vivo modification of refractive power of an intraocular lens implant

Info

Publication number: CA2106809A1
Application number: CA002106809A
Authority: CA
Inventors: Francis E. O'donnell, Jr.
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-24
Filing date: 1993-09-23
Publication date: 1994-03-25
Also published as: US5549668A; US5288293A; US5725575A

Abstract

Abstract of the Disclosure A method for changing the refractive power (spherical and astigmatical) of an intraocular implant of the type having a lens, either formed of a series of laminates of material, or having a lens that is coated with material, said material, when subject to laser energy providing for its expansion or contraction, and thereby varying the curvature of the lens, and hence, effecting an increase or decrease in its relative refractive index or power. The direction at which the laser energy is applied to the lens can effect the relative change in the refractive power of the lens. A modification provides haptics diametrically or concentrically extending from the optic lens, with a segment of material such as hydrogel or collagen at the juncture between the haptics and the lens, which when directionly exposed to laser energy, can cause an increase or decrease in the relative refractive power of the implanted lens.

Description

2~ ~i sackground of the Invention Thls invention relates to in vivo modification o~
refractive power of an intraocular lens implant, and more specifically, the invention pertains to a method of changing the refractive power of an intraocular lens by the use of laser energy, generally after the lens has been implanted.
It ls well accepted that the insertlon of an intraocular lens is the best solution for corrective vision after cataract surgery. Intraocular lenses and methods of inserting them are known to the art. ~or example, the United States patent No. 4,056,855, to Kelman, discloses an intraocular lens and a method of implanting same through an incision in the eye. The assembly includes a lens member and supporting wire initially in a dissasembled condition and adapted to be introduced through a small incision in the eye.
United States patent No. 4,608,049, also to Kelman, discloses an intraocular lens which may be inserted into the eye through a smaller incision in the cornea. United States patent No.
4,693,716, to MacKool, discloses an intraocular lens and implant including a lens centered on a lens axis. United States patent No. 4,813,954, to Siepser, discloses a compression, deformation, and dehydration method of fabrication and implantation of an expanse aisle, hydrogel intraocular lens. The problems associated with the foregoing patents include the fact that once the intraocular lens is implanted, , 2J.~ 2~!~

it is not possible to change the refractive power of the implanted lens. Thus, when further correction becomes necessary, they must be replaced. Unlted States patent No.
5,041,134, to O'Donnell, the inventor herein, discloses an intraocular lens assembly for lmplantlng in the posterior chamber of a human eye after an exttacapusular extraction. The intraocular lens assembly includes an optic holder having haptic elements for locating and positioning the optic holder in a fixed position within the posterior chamber of the eye and its optic lens releasably secured to the optic holder for interchange of different optic lenses as needed without removing the entire optic holder from the eye. This will allow changing of the refractive index of the implant without removal of the entire implant, but still the lens itself must be replaced. The patent to Schachar, No. 4,373,281, discloses a variable power intraocular lens and method of implanting same, the lens including a fluid expandable sac, which includes the lens portion, and a valve portion, that extends through sclera of the eye so that the fluid is subject to valve action which apparently can change the fluid expandable sac in order to vary the lens refraction. This patent requires the use of an electrode and microprocessor for changing the index of refraction of the intraocular lens to respond to desired parameters, but does not disclose the use of the laser to make the fine adjustments in the refractive power of the lens.

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United States patent No. 4,669,466, to L'Esperance, discloses a method and apparatus for the analysis and correction of abnormal refractive errors of the eye. This invention discloses instrumentation for performinq refraction-corrective surgery directly to the cornea. United States patent No. 4,665,913, also to L'Esperance, discloses another related method for ophthalmological surgery uslng a laser, but is limited to use upon the anterior surface of the cornea of the eye and not an intraocular lens lmplant. Unlted States patent No. 4,676,790, to Kern, shows a method of manufacture and implantation of corneal lnlays. A laser ls used for milling into the surface of the cornea, to form a recess, so that when the implant is applied, its surface lies - flush with the corneal membrane. This invention does not utilize lasers for changing the index, but simply provides lasers for use for inlaying an implant within the corneal surface.
Another patent to L'Esperance, No. 4,718,418, discloses another apparatus for ophthalmological surgery utilizing a laser for contouring the surface of the cornea to eliminate astigmatism and to provide a corneal curvature correction.
The United States patent No. 4,793,344, to Cumming, et al, discloses a method for preparing corneal donor tissue for refractive eye surgery.

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Finally, United States patent No. 4,923,467, to Thompson, shows an apparatus and process for application and adjustahle reprofiling of synthetic lenticules for vision correction. This disclosure defines the process of ablating, by laser, a groove in the cornea, to receive the peripheral edge of the lmplant lens, and then utilizinq the laser to deliver a reprofiling of the lenticule for reflning its refractive power, None of the aforementioned art utilizes laser energy to change the refractive power of an existing len~ of the invention. It is therefore, an object of this invention to provide a method of correction of the refractive power of an implanted intraocular implant by using laser energy to alter the refractive power of the implanted lens. Both the spherical and astigmatic power could be modified and, multifocality could be provided.
Another object of the invention is to provide a method of modifying the implant power of an intraocular implant by changing the state of internal hydration of the intraocular implant.
Yet another object of this invention is to provide a method for changing the refractive power of an intraocular implant by using laser energy to collapse the internal layer of the intraocular implant thereby causing a reduction in the frontal curvature.
Still a further object of this invention is to provide a method for changing the refractive power of an intraocular , .

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implant by using laser energy to contract an internal layer of the intraocular implant, therby causing expansion and the increase of curvature of the implant surface, thereby increasing refractive power.
Still another object of this invention is to provide a method for changing the refractive power of an intraocular implant by altering the curvature of the implant by direct surface treatment of the implant with laser energy.
Another object of the present invention is to provide a method of changing the refractive power of the intraocular lens by applying laser energy to modify the haptic-optic angle of the intraocular implant, thereby causing motion of the optic to either increase or decrease the relative refractive power of the optic.

Summary of the Invention Briefly stated, this invention relates to a method of changing the refractive index of a intraocular implant in vivo by applying laser energy to the intraocular implant so as to open microfenestrations in the implant, and hence allowing increasing hydration of the internal layer, thereby increasing the front curvature and increasing their refractive power. In another embodiment of the present invention, laser energy is applied to an intraocular implant in vivo to cause the collapse of an internal layer of the implant thereby causing a reduction .', , ' ' ' ' .: ~., ~ . :

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of the front curvature. Laser energy is applied to an intraocular implant to contract an internal layer of the intraocular implant thereby causing expansion and increased curvature of the surface, increasing refractive power. In another embodiment of the present invention, laser energy is applied directly to the surface of an intraocular implant, thereby changing the curvature of the implant and thereby increasing or decreasing the refractive power of the implant.
And, in another embodiment of the present invention, laser energy is applied to the haptic optic angle of a introcular lens assembly, either causing forward motion of the optic, thereby increasing the relative refractive power, or causing backward motion of the implant causing decrease in the relative refractive power.
This invention contemplates the development of an implant lens which may have its refractive index varied even after it has been implanted into the eye. The variation preferably is done throùgh the use of a laser, which causes an expansion or contraction of select components of the lens, to achieve its index variation. Or, this invention yet recognizes that the refractive power for the intraocular lens may be varied, even before it is implanted into the eye, so that the changes may be made in sito by the ophthalmologist, after determining the extent of correction required to improve the vision of the patient, before the lens implant is made.

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The invention utilizes a multicomponent lens, that may be made up of various laminate components, with the front and back layers for the lens being formed of a material such as silicone, collagen, polyacrylamide, a soft PMMA, or the like.
The center layer for the lens, arranged intermediately the front and back segments, may be formed of a hydrogel, or other collagen Thus, it is the change in state o~ the internal hydration, particularly of the hydrogel component, that causes the lens to vary in shape, and thereby varying the refractive index, to correct for any error in vision, for the patient.
Normally, the purpose of this invention is to provide for achievi`ng the correct spherical and cylindrical residual refractive power, after any error has eventually become inherent in the implanted lens, following implant surgery which may have taken place at some previous time, in order to reach that power necessary for the patient to have reasonably clear avoided vision. In addition to the foregoing, in order that the hydrogel layer may have a greater effect in achieving the change in curvature of the lens, during treatment by the laser, the intermediate layer may have a series of upstanding integral columns, arranged around the periphery of the front layer of the lens, so that the increasing of the hydration of the intermediately arranged layer will increase the front curvature of the lens, thereby increasing its refractive power. These upright columns of the hydrogel layer are intended to provide , .

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. .. c ': ' ' ' 21~ j'~i3',' an access for the laser directly to the intermediate segment, and these columns function as a waterproof-membrane covered microfenestrations, that allow aocess to the said center layer. Thus, through the use of the laser, a collapse may be attained for the internal layer, which causes a reduction ln the front curvature, thereby reducing the surface curvature and the refractive power of the lens. To the contrary, the laser energy may be used to contract, or heat up, the internal layer B, to cause its expansion, and increase the curvature of the frontal surface, thereby increasing the refractive power of the lens.
As an alternative, thè~hydrogel may be located at the junction between the haptic holding the optic lens in place, and when the laser is applied to the arranged hydrogel, or related material, it causes a change in variation in the haptic-optic angle, thereby effecting a change in the implant power. Thus, applying laser energy to, for example, the frontal surface of the juncture may cause a forward motion of the optic, causing its increase in relative refractive power.
Applying the laser energy to the backside thereof, may cause a backward motion to the implant, thereby effecting a decrease in its relative refractive power. These are examples as to how the optics of the intraocular lens may be varied, to cause a variation and modification in its refractive power, so as to improve the vision of the patient in whom the lens has _ 9 _ .

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2 ~Ofi~`O') been previously implanted, but requires a variation in the same, either immediately after surgergy, so as to fine tune the viewing by the patient through the newly implanted lends, or at some subsequent date, when a corrective variation in the refractive power of the lens becomes necessary in order to further improve vision.
Variations in this concept for providing means for varying the refractive power of an intraocular lens, either before the lens is implanted, or preferably after it has been implanted by the physician, may occur to those skilled in the art upon reviewing the summary of the invention, in addition to undertaking a study of the description of its preferred embodiment, in light of the drawings.

Brief Description of the Drawings In referring to the drawings, Fig. 1 provides a schematic side view showing the laminations for the intraocular lens of this invention Fig. 2 is a top plan view thereof;
Fig~ 3 is a schematic side view of a modification to the lens of Fig. l;
Fig. 4 is a schematic side view of the lamination of the lens of Fig. l;

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Fig. 5 discloses a lens with haptics showing a modiEication in the method for attaining variation in the refractive power of a lens; and Fig. 6 is a front view thereof.

Description of the Preferred Embodiment . _ _ As previously reviewed, the concept of this invention is to allow usage of a laser device to modify the curvature, either at the front or back, of an optic lens, of the implant type, which may be fabricated from material that is subjected to degrees of hydration, whether the lens be formed totally or partially of a silicone, hydrogel, PMMA, collagen, or the like. Preferably, the modification can be made after the intraocular lens has been implanted or inserted into the eye.
More specifically, this concept is to provide a way to fine tune the refractive power of the implant in vivo. The laser energy utilized could be at any normal and usable wave length such as 1064 nanometer, with the laser being directed and aimed at the ~urface, either the front or back, of the implant optic, or at its intermediate lamination, with the purpose of changing the curvature, and as a result, the refractive power of the implanted lens. In general, the implant lens might be coated with an inert surface material to facilitate a surface curvature change when exposed to the effect of the laser. This surface might be enclosed in order to confine resultant debris. Alternatively, the laser energy could be 21 ~ X, (` ') aimed at the haptic-lens implant junction, to alter the anterior-posterior position o~ the implant, relative to its haptic, and thus change the residual refractive error of the eye. Normally, the more anterior the location of the optic, the less plus power refractive power variation or change will be necessary.
Finally, the implant could he used to altar the states of hydration of the optic and thus change the shape and hence the refractive power of the implant, through laser application.
More specifically, in referring to Fig. 1, a schematic is provided of the type of implant lens that may be used in this invention, the lens being shown at 1. It may include a series of of laminations, wherein a frontal and curved section of the lens that adds the refractive power to it, is shown at 2, while the posterior lamination 3 may be formed of the same material. Generally, various types of compositions that may be formed into these frontal and back laminations may include silicone, a collagen, a polyacryalmide, or a soft PMMA, or the like. The essence of the invention, though, is to provide a layer of material, generally intermediately disposed, as can be seen at 4, and which is designed to provide for an increasing in the hydration of said layer, when exposed to laser energy, whereby the laser may be used to open the microfenestrations of `~ the material forming this intermediate layer, to thereby increase the front curvature of the lens, and thereby enhance the refractive power of the implant. This increasing of '', '' ..' ' . ' . "''. ,.' ;. ' .' .' ' ` ~
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hydration, through exposure of the intermediate layer to laser energy, enhances its hydration, to thereby force the frontal layer into a greater curvatllre, to add to the plus power of the refractive index for the constructed lens. As can be further seen, and as shown in Fig. 2, the intermediate layer 4, which may be formed of a hydrogel or collagen, may have upwardly extending columns, as at S, that extend through the anterior laminate 2, so as to provide a path for direction of the laser energy, to increase the hydration of the column S segments, but also to focus the laser energy into the hydrogel layer 4, as previously explained. Generally, the columns 5, while formed of the hydrogel or collagen type material, which may be subject to increased hydration, when exposed initially to laser energy, may be lined or covered with a waterproof-membrane, as at 6, so as to focus the laser energy in its direction upon the hydrogel material itself making up the laminate B, and its integral columns 5.
As can be seen in Fig. 3, which shows a slight modification to the method of fabricating the intraocular lens, it includes similar type of layers making up the laminate of Fig. 1, wherein the anterior and posterior layers 7 and 8, respectively, may be formed of the same composition as previously described. The intermediate laminate 9 will likewise be formed of a laver of material such as hydrogel or collagen that may have increased hydration when exposed to the ~ 13 -- ~ .
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~:~ G~ s~ 3 initial laser energy. But, when further exposed to laser energy, such that evaporation of some moisture of the hydrogel layer 9 may be encountered, there may be a collapse of the layer 9, which causes a reduction in the front curvature of the lens, and therefore, the inducement of a lessening of the refractive index of the formed lens. This provides a correction in the focal power of the lens but in an opposite direction. The laser energy is used to collapse the internal layer, thereby reducing the surface curvature of the anterior lens 7, and thereby reducing its refractive power. When the laser energy is initially used to contact the intermediate layer 9, its energy will heat up this intermediate layer B, causing an expansion and increase in the curvature of the ,~ anterior lens 7, thereby increasing the refractive power of the implant lens. -Fig. 4 discloses a side view of an anterior lens, similar to that as previously reviewed with respect to the lens laminate 2 of Fig. 1, and the laminate 7 of Pig. 2. The material forming the anterior lens 10 will likewise be of a silicone, collagen, polyacrylamide, or soft PMMA, or the like.
The impingement of the laser energy directly onto the lens 10 attains a focal point at its back surface, approximately at the location 11, and may have a tendency to initially heat up ` and expand the lens layer 10, to cause an increase in its refractive power, or after continuing exposure of the .
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material to the laser energy, may cause a reduction in its moisture content, and a consequential collapse of its interior layer, thereby reducing the refractive power of the implant lens. ~n the other hand, by directinq the laser energy onto the front surface of the lens 10, this may tend to increase its curavature, and thereby increase its refractive power, or by directing the laser energy onto the back surface of the lens 10, causing a reduction in its front curvatuce, thereby decreasing the refractive power of the intraocular lens. These are examples as to how laser energy may be applied to an implant lens, or various laminates forming it, and which has an effect ~pon its hydration, to very its shape or curvature, and consequently, its refractive power.
Furthermore, the implant lens may have a special coating upon it, to facilitate this change of curvature, when exposed to laser energy. For example, a PMMA optic coated with silicone, collagen, or hydrogel, may have greater susceptibility to hydrate, or dehydrate, when exposed at various locations to the laser energy, to thereby change its shape, and hence its refractive power.
It is also likely that the technique of intrastromal or surface laser modification, as explained in the examples above, could also be applied to injectable implants, of the type that are used to replace a lens of the eye, after a cataract removal. Injectable implants are designed to fill the , ' ~

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capsular bag after endocapsular removal of the cataract has been performed through surgery.
A further modification to the suhject matter of this invention, whereby the optic lens may have its refractive index varied, even after it had heen previously implanted, can be seen in Figs. 5 and 6. In this particular instance, there may be a material that is formed at the juncture between the haptic, such as those shown at 12 and 13, and which connect to the implant lens 14. At this juncture there may be located the material 15 that may be more readily sub~ectable to hydration, or dehydration, such as the type of hydrogel or collagen as previously explained. Thus, modifying the haptic-optic angle, through laser energy treatment, provides for an effect in the change in the implant power. Thus, applying laser energy from the front of the lens, as can be seen from the direction 16, may have a tendency to cause the optic to move forwardly, and thereby increase its relative refractive power, as may be required. On the other hand, applying the thermal laser energy, or laser treatment, from the rear, as in the direction of the arrow 17, may cause a backward motion to the implant, thereby effecting a decrease in its relative refractive power, and a lessening of its refractive index, as may be further required for viewing correction. These are just examples as to how the optic lens, and its location, or its shape or configuration, may be varied by treatment with thermal laser . : . , , . :
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energy, to inherently effect the refractive power of the implanted lens, even at a subsequent date, in order to provide further correction to the patient's ability to view.
variations or modifications to the subject matter of this invention may occur to those skilled in the art upon reviewing the subject matter herein. Such varlations or modifications, if within the spirit of this invention, are intended to be encompassed within the scope of any claims to patent protection issuing upon this development. The description of the preferred embodiment set forth herein, and its variations, are provided for illustrative purposes only.

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Claims

1. A method for changing the refractive spherical and astigmatic power of an intraocular implant comprising:
aiming a laser surgical device at the surface of the intraocular implant;
activating the laser energy of the surgical device;
applying said laser energy to a surface of the intraocular implant;
changing the shape of the intraocular implant until the required curvature is achieved; and, deactivating said laser energy.

2. The method of claim 1 wherein applying said laser energy to a surface of the intraocular implant further comprises applying said laser energy to a coating of silicone on such implant.

3. The method of claim 1 wherein the step of applying said laser energy to a surface of the intraocular implant further comprises applying said laser energy to a coating of collagen on such implant.

4. The method of claim 1 wherein the step of applying said laser energy to a surface of the intraocular implant further comprises applying said laser energy to a coating of hydrogel.

5. A method of changing the refractive power of an intraocular implant assembly composed of a haptic and an optic, comprising:
aiming a laser at a haptic-optic angle of such implant activating said laser energy;
applying said laser energy to said haptic-optic angle; and causing a motion of the optic thereby changing the relative refractive power of such implant.

6. The method of claim 5 wherein the step of causing a motion of the optic further comprises causing a forward motion of said optic thereby causing an increase in the relative refractive power.

7. The method of claim 5 wherein the step of causing a motion of the optic further comprises causing a backward motion of said optic thereby causing a decrease in the relative refractive power.

8. A method of changing the refractive index of an intraocular implant, comprising:
aiming a laser at such intraocular implant;
activating laser energy;
applying said laser energy to a surface of such implant thereby opening a plurality of microfenestrations on such implant; and increasing hydration of an internal layer of such implant thereby increasing the front curvature of such implant to increase the refractive power.

9. The method of claim 8 wherein the step of applying laser energy to a surface of such implant further comprises applying laser energy to a silicone surface.

10. The method of claim 8 wherein the step of applying laser energy to a surface of such implant further comprises applying laser energy to a collagen surface.

11. The method of claim 8 wherein the step of applying laser energy to a surface of such implant further comprises applying laser energy to a polyacrylamide surface.

12. The method of modifying an optic implant power in vivo, comprising:
aiming a laser at such optic implant;
activating laser energy;
applying said laser energy to an internal layer of such optic implant;
changing the dimension of such internal layer thereby changing the curvature of an external layer thereby changing the refractive power of such optic.

13. The method of claim 3 wherein said step of changing the dimension of said internal layer further comprises collapse of said internal layer thereby causing a reduction in curvature of an external layer and thereby reducing the refractive power.

14. The method of claim 12 wherein said step of changing the dimension of said internal layer further comprises heating said internal layer and causing said internal layer to expand thereby increasing the curvature of an external layer, thereby increasing their refractive power.

15. An intraocular lens implant capable of having its refractive power changed, even after the lens has been formed, including said lens incorporating a series of laminates, at least one of the laminates having curvature for providing the refractive power for correcting viewing through the lens, and at least a second laminate formed of a material subject to one of hydration and dehydration and when exposed to laser energy changing in the refractive power of the formed lens.

16. The invention of claim 15 wherein said lens being formed of three laminates, two of said laminates forming respectively the front and back of the lens, and the third laminate forming an intermediate segment, the first two laminates formed of one of a silicone, collagen, polyacrylamide, and soft PMMA, with the intermediate laminate formed of one of hydrogel and collagen.

17. The invention of claim 16 and wherein a series of columns extending through the front laminate, said columns being formed of the same material and being integral with the intermediate laminate.

18. An intraocular lens implant formed of material which when subjected to laser energy providing for a variation in its refractive power, said lens constructed of material shaped to provide a frontal curvature, to provide an index of refraction for the formed lens, said lens being made of one of silicone, collagen, polyacrylamide, and soft PMMA, and said lens being coated upon one of its front and back surfaces with one of silicone, collagen, and hydrogel, which when exposed to laser energy, causes a change in curvature of the formed lens and a resultant increase or decrease in its refractive index.

19. An intraocular lens implant formed of materials when subjected to laser energy providing for a variation in its refractive power, wherein said implant incorporating an optic lens, a pair of haptics extending from approximate opposite side of said optic lens, and a segment of material located at the juncture where the haptics connect with the optic lens, said material being subject to expansion or contraction when exposed to laser energy, such when laser energy is directed upon the segment of material providing for a variation in the angular relationship between the haptics and the optic lens.

20. The invention of claim 19 wherein directing laser energy upon the front of the segment of material provided adjacent the optic lens provides an increase in the relative refractive power of the said lens, and directing the laser energy upon the back of the segment of material causing a decrease in the relative refractive power of the optic lens.