US20030048411A1

US20030048411A1 - Intraoccular lenses capable of in vivo power adjustment and method for same

Info

Publication number: US20030048411A1
Application number: US10/192,017
Authority: US
Inventors: Jagdish Jethmalani; Robert Maloney; Robert Grubbs; Julia Kornfield; Christian Sandstedt; Daniel Schwartz
Original assignee: REGENT OF UNIVERSITY CALIFORNIA OF; California Institute of Technology CalTech
Current assignee: REGENT OF UNIVERSITY CALIFORNIA OF; California Institute of Technology CalTech
Priority date: 1999-01-12
Filing date: 2002-07-10
Publication date: 2003-03-13
Also published as: WO2000041650A1; JP5411099B2; CN1346251A; US20030090624A1; US20030093150A1; MXPA01007051A; EP1139921A1; US20030151719A1; CA2360583A1; US20070035698A1; JP2011034091A; US6824266B2; US7837326B2; BR9916895A; US6813097B2; EP1139921B1; US7210783B2; AU6426799A; US7798644B2; US20070260311A1

Abstract

A method for evaluating the effectiveness of adjustable optical implants is provided The implants are first inserted into a test subject. The implant is then exposed to an external stimulus, such as light, to induce a change in the properties of the implant. The implants are then evaluated to determine the nature and extent of the change in properties.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. application Ser. No. 09/416,044 filed Oct. 8, 1999; which claims priority of U.S. Provisional Application No. 60/115,617 filed Jan. 12, 1999; claims priority of U.S. Provisional Application No. 60/132,871 filed May 5, 1999; and claims priority of U.S. Provisional Application No. 60/140,298 filed Jun. 17, 1999; and which is fully incorporated herein by reference.[0001]

TECHNICAL FIELD

The present invention is directed to a system and method which relates to a novel method for evaluating optical implants such as intraoccular lenses (IOLs). In the present invention, the implants are placed in a non-human test subject and evaluated for biocompatibility and operability. The method is useful in the design of novel implants as well as obtaining data concerning the safety and operability of the lenses. The method is particularly applicable to novel IOLs whose optical properties can be manipulated after the lens has been implanted.

BACKGROUND OF THE INVENTION

Optical implants have long been used to correct vision problems or to affect changes in “subjects” vision. The most widely used optical implant in the intraoccular lens (IOL) which is used to replace a patient's natural lens when the lens can no longer function. IOLs are most often used when a patient develops cataracts such that normal vision is impossible.

Until recently, the optical properties of optical implant such as IOLs were predetermined prior to implantation. In the case of IOLs, the ophthalmologist would estimate such properties as the lens power and shape based on pre-operation examination of the patient's eye. A lens meeting those requirements would then be implanted into the eye after the natural lens was removed. While these procedures are generally successful in restoring sight to a patient, until recently, there was no noninvasive procedure for adjusting the optical properties of the lens. Thus, if the surgeon's estimates were incorrect, the patient might still be required to use spectacles or the like to achieve optimum vision.

Recently, a novel type of optical implant has been developed which allows for manipulation of the optical properties of the implant after it has been implanted in the patient. PCT/US99/23728 discloses a novel implant whose optical properties can be adjusted post fabrication by one or more regions of the implant to an external stimulus such as light. These novel implants allow a surgeon to adjust the optical properties of an IOL after it has been implanted.

BRIEF SUMMARY OF THE INVENTION

The invention is a method that allows for testing of both the safety and operability of optical implants. In one embodiment, it is a method for evaluating the safety and operability of novel IOLs whose optical properties can be manipulated in vivo.

In practice of the invention, an optical implant is implanted in a non-human test subject. After allowing for wound healing, the implant is then evaluated for biocompatibility and operability. By operability, we mean adjustment of lens dose. In the case of implants which are capable of post implant manipulation of optical properties, this includes manipulating the optical properties in the prescribed manner and then evaluating the implant to set if the desired changes occur and are maintained for the desired time period.

In a preferred embodiment, the method involves implanting an adjustable IOL in a non-human test subject. By the term “Adjustable IOL” we refer to IOLs whose optical properties can be manipulated or adjusted post implantation without resort to invasive procedures. Generally, this is accomplished by preparing an implant which has macromers distributed therein. These macromers respond to external stimuli such as light, causing changes in the optical properties of the implant. A more detailed description of these types of implants can be found in PCT/US 99/23728.

After the implant has been placed in the test subject, and following wound healing, the optical properties of the lens are manipulated in the prescribed manner. In the preferred method, this is accomplished by exposing the lens to an external stimulus, such as light. Ultraviolet light is most preferred.

After the optical properties have been manipulated in the desired manner, the implants are then evaluated for safety, including biocompatibility, and operability, e.g. whether the desired changes in optical properties have taken place. These tests are done using standard methods such as examining the test subject's eyes for evidence of inflammation and physical examination of the lens implant for changes in optical properties. These evaluations can occur either in vivo or ex vivo.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: [0012]
FIG. 1 is a graph showing the measured change in dioptor for series of adjustable IOLs after an adjustment to the lenses was made in vivo.[0013]

DETAILED DESCRIPTION OF THE INVENTION

The method of the invention is a means for evaluating the biocompatibility and operability of adjustable optical implants such as IOLs. The method involves placing the adjustable implant in a non-human test subject, allowing wound healing to occur and then determining if the implant poses safety or health risks to the subject. The method further comprises evaluating the operability of the lens in vivo. By operability is meant whether the implant can be adjusted in the manner intended. [0014]
The term optical implant refers to any devices or structure implanted in a living organism for the purpose of changing the optical properties of the organisms eyes. Perhaps the most common optical implant is an intraoccular lens the organisms natural lens when the lens becomes damaged or no longer transmits light. As described more fully below, adjustable optical implants are those optical implants, such as IOLs whose properties can be manipulated or adjusted post implantation by non-invasive measures. In the preferred embodiment, the adjustable implants contain macromers which are capable of inducing change in the implant when the implant is exposed to an external stimulus. [0015]
Non-human test subject refers to a test subject, other than a human being into which the optical element is implanted. Typically this includes mammals which exhibit physiological similarities to humans and includes rabbits, dogs, pigs and chimpanzees or other simians. Of these, rabbits and pigs are most preferred. [0016]
The first step of the method involves implanting the optical implant into the test subject. In the case of an IOL this involves first removing the existing lens using any standard technique such as phaecoemulsification. Removal of the lens creates a cavity within the capsular bag into which the IOL is then placed. The IOL is inserted using standard techniques such as that described in Clayman, Intraoccular Lens Implantation, 1985. Alternatively, the IOL can be formed in situ in sets using a procedure describes in Nishi, O. et al, 23 J. Cataract. Refract. Surg. 1548-53 (1997). [0017]
Once the implant is in place and the incision closed, the wound created by the placement of the implant is allowed to heal. This typically takes from 7 to 14 days. [0018]
Following wound healing the optical implants are then evaluated for safety and if desired, operability. Safety evaluation includes testing and observations for biocompatibility including absence of infection and resistance to leaching of components and degradation. Operability evaluation includes a determination as to whether the implants perform as designed. In the case of implants capable of adjustment or manipulation of function preferably optical properties, this includes attempting adjust or manipulate the optical properties of the implant in vivo and then evaluating the implant to determine whether a change in the implant has occurred and the nature and degree of the change. [0019]
In the preferred embodiment, the method of the invention comprises a method for evaluating the safety and operability of IOLs that are capable of adjustment or manipulation of their optical properties by non-evasive success. In one embodiment the IOLs contains macromers which, when exposed to an external stimulus, induce changes in the optical properties of the IOL. In the most preferred embodiment, the optical properties of the implant are manipulated by stimulus induced polymerization of the macromers causes changes in the refractive index of the implant, the shape of the implant or both refractive index and shape. The preferred stimulus used to induce polymerization of the macromers is light with ultraviolet light most preferred. [0020]
To determine the operability of the IOLs after implanting them in the test subject, the IOLs are exposed to an external stimulus, such as ultraviolet light, in a prescribed pattern, intensity, and duration. The pattern, intensity and duration of the exposure is determined by the desired changes of optical properties and the nature of the macromers and other components dispersed throughout the IOL. Once the IOL has been exposed to the external stimulus, it is left in the eye for further evaluation of the IOLs safety and biocompatibility. This is done by observing the eye for signs of infection, migration of material from the IOL and the like which are indicator, that the lens is not biocompatible. [0021]
The IOLs are also examined to determine if the desired change in optical properties has occurred. This can be accomplished in several ways including physical examination of the lens in vivo to see if the desired change in shape has occurred, use of refractive techniques to see if the desired change in refractive has occurred and explantation of the lens followed by examination of the change in optical properties ex vivo. While these are the preferred methods of evaluating the performance of the IOL, other techniques are known. [0022]
One type of optical element which can be evaluated using the novel method described herein are optical elements that are capable of post operative adjustment of their properties. One class of these elements is optical elements that comprise a first polymer matrix and a macromer dispersed therein. The first polymer matrix forms the optical element framework and is generally responsible for many of its material properties. The macromer (“macromer”) may be a single compound or a combination of compounds that is capable of stimulus-induced polymerization, preferably photo-polymerization. As used herein, the term “polymerization” refers to a reaction wherein at least one of the components of the macromer reacts to form at least one covalent or physical bond with either a like component or with a different component. The identities of the first polymer matrix and the macromers will depend on the end use of the optical element. However, as a general rule, the first polymer matrix and the macromers are selected such that the components that comprise the macromer are capable of diffusion within the first polymer matrix. Put another way, a loose first polymer matrix will tend to be paired with larger macromer components and a tight first polymer matrix will tend to be paired with smaller macromer components. [0023]
Upon exposure to an appropriate energy source (e.g., heat or light), the macromer typically form a second polymer matrix in the exposed region of the optical element. The presence of the second polymer matrix changes the material characteristics of this portion of the optical element to modulate its refraction capabilities. In general, the formation of the second polymer matrix typically increases the refractive index of the affected portion of the optical element. After exposure, the macromer in the unexposed region will migrate into the exposed region over time. The amount of macromer migration into the exposed region is time dependent and may be precisely controlled. If enough time is permitted, the macromer components will re-equilibrate and redistribute throughout optical element (i.e., the first polymer matrix, including the exposed region). When the region is re-exposed to the energy source, the macromer (“macromer”) that has since migrated into the region (which may be less than if the macromer composition were allowed to re-equilibrate) polymerizes to further increase the formation of the second polymer matrix. This process (exposure followed by an appropriate time interval to allow for diffusion) may be repeated until the exposed region of the optical element has reached the desired property (e.g., power, refractive index, or shape). At this point, the entire optical element is exposed to the energy source to “lock-in” the desired lens property by polymerizing the remaining macromer components that are outside the exposed region before the components can migrate into the exposed region. In other words, because freely diffusable macromer components are no longer available, subsequent exposure of the optical element to an energy source cannot further change its power. FIG. 1 illustrates one inventive embodiment, refractive index modulation (thus lens power modulation) followed by a lock in. [0024]
The first polymer matrix is a covalently or physically linked structure that functions as an optical element and is formed from a first polymer matrix composition (“FPMC”). In general, the first polymer matrix composition comprises one or more monomers that upon polymerization will form the first polymer matrix. The first polymer matrix composition optionally may include any number of formulation auxiliaries that modulate the polymerization reaction or improve any property of the optical element. Illustrative examples of suitable FPMC monomers include acrylics, methacrylates, phosphazenes, siloxanes, vinyls, homopolymers and copolymers thereof. As used herein, a “monomer” refers to any unit (which may itself either be a homopolymer or copolymer) which may be linked together to form a polymer containing repeating units of the same. If the FPMC monomer is a copolymer, it may be comprised of the same type of monomers (e.g., two different siloxanes) or it may be comprised of different types of monomers (e.g., a siloxane and an acrylic). [0025]
In one embodiment, the one or more monomers that form the first polymer matrix are polymerized and cross-linked in the presence of the macromer. In another embodiment, polymeric starting material that forms the first polymer matrix is cross-linked in the presence of the macromer. Under either scenario the macromer components must be compatible with and not appreciably interfere with the formation of the first polymer matrix. Similarly, the formation of the second polymer matrix should also be compatible with the existing first polymer matrix. Put another way, the first polymer matrix and the second polymer matrix should not phase separate and light transmission by the optical element should be unaffected. [0026]
As described previously, the macromer may be a single component or multiple components so long as (i) it is compatible with the formation of the first polymer matrix; (ii) it remains capable to stimulus-induced polymerization after the formation of the first polymer matrix; and (iii) it is freely diffusable within the first polymer matrix. In preferred embodiments, the stimulus-induced polymerization is photo-induced polymerization. [0027]
The inventive optical elements have numerous applications in the electronics and data storage industries. Another application for the present invention is as medical lenses, particularly as intraoccular lenses. [0028]
In general, there are two types of intraoccular lenses (“IOLs”). The first type of an intraoccular lens replaces the eye's natural lens. The most common reason for such a procedure is cataracts. The second type of intraoccular lens supplements the existing lens and functions as a permanent corrective lens. This type of lens (sometimes referred to as a phakic intraoccular lens) is implanted in the anterior or posterior chamber to correct any refractive errors of the eye. In theory, the power for either type of intraoccular lenses required for emmetropia (i.e., perfect focus on the retina from light at infinity) can be precisely calculated. However, in practice, due to errors in measurement of corneal curvature, and/or variable lens positioning and wound healing, it is estimated that only about half of all patients undergoing IOL implantation will enjoy the best possible vision without the need for additional correction after surgery. Because prior art IOLs are generally incapable of post-surgical power modification, the remaining patients must resort to other types of vision correction such as external lenses (e.g., glasses or contact lenses) or cornea surgery. The need for these types of additional corrective measures is obviated with the use of the intraoccular lenses of the present invention. [0029]
The inventive intraoccular lens comprises a first polymer matrix and a macromer dispersed therein. The first polymer matrix and the macromer are as described above with the additional requirement that the resulting lens be biocompatible. [0030]
Illustrative example of a suitable first polymer matrix include: poly-acrylates such as poly-alkyl acrylates and poly-hydroxyalkyl acrylates; poly-methacrylates such as poly-methyl methaacrylate (“PMMA”), poly-hydroxyethyl methacrylate (“PHEMA”), and poly-hydroxypropyl methacrylate (“HPMA”); poly-vinyls such as poly-styrene and poly-vinylpyrrolidone (“PNVP”); poly-siloxanes such as poly-dimethylsiloxane; poly-phosphazenes,and copolymers of thereof. U.S. Pat. No. 4,260,725 and patents and references cited therein (which we all incorporated herein by reference) provide more specific examples of suitable polymers that may be used to form the first polymer matrix. [0031]
In preferred embodiments, the first polymer matrix generally possesses a relatively low glass transition temperature (“T[0032] _g”) such that the resulting IOL tends to exhibit fluid-like and/or elastomeric behavior, and is typically formed by crosslinking one or more polymeric starting materials wherein each polymeric starting material includes at least one crosslinkable group. Illustrative examples of suitable crosslinkable groups include but are not limited to hydride, acetoxy, alkoxy, amino, anhydride, aryloxy, carboxy, enoxy, epoxy, halide, isocyano, olefinic, and oxime. In more preferred embodiments, each polymeric starting material includes terminal monomers (also referred to as endcaps) that are either the same or different from the one or more monomers that comprise the polymeric starting material but include at least one crosslinkable group. In other words, the terminal monomers begin and end the polymeric starting material and include at least one crosslinkable group as part of its structure. Although it is not necessary for the practice of the present invention, the mechanism for crosslinking the polymeric starting material preferably is different than the mechanism for the stimulus-induced polymerization of the components that comprise the Macromer. For example, if the Macromer is polymerized by photo-induced polymerization, then it is preferred that the polymeric starting materials have crosslinkable groups that are polymerized by any mechanism other than photo-induced polymerization.
An especially preferred class of polymeric starting materials for the formation of the first polymer matrix is poly-siloxanes (also known as “silicones”) endcapped with a terminal monomer which includes a crosslinkable group selected from the group consisting of acetoxy, amino, alkoxy, halide, hydroxy, and mercapto. Because silicone IOLs tend to be flexible and foldable, generally smaller incisions may be used during the IOL implantation procedure. An example of an especially preferred polymeric starting material is bis(diacetoxymethylsilyl)-polydimethylsiloxane (which is poly-dimethylsiloxane that is endcapped with a diacetoxymethylsilyl erminal monomer). [0033]
The macromer that is used in fabricating IOLs is as described above except that it has the additional requirement of biocompatibility. The macromer is capable of stimulus-induced polymerization and may be a single component or multiple components so long as (i) it is compatible with the formation of the first polymer matrix; (ii) it remains capable of stimulus-induced polymerization after the formation of the first polymer matrix; and (iii) it is freely diffusable within the first polymer matrix. In general, the same type of monomers that is used to form the first polymer matrix may be used as a component of the macromer. However, because of the requirement that the macromer monomers must be diffusable within the first polymer matrix, the macromers generally tend to be smaller (i.e., have lower molecular weights) than the monomers which form the first polymer matrix. In addition to the one or more monomers, Macromer may include other components such as initiators and sensitizers that facilitate the formation of the second polymer matrix. [0034]
In preferred embodiments, the stimulus-induced polymerization is photo-polymerization. In other words, the one or more monomers that comprise the macromers each preferably includes at least one group that is capable of photopolymerization. Illustrative examples of such photopolymerizable groups include but are not limited to acrylate, allyloxy, cinnamoyl, methacrylate, stibenyl, and vinyl. In more preferred embodiments, the macromer includes a photoinitiator (any compound used to generate free radicals) ether alone or in the presence of a sensitizer. Examples of suitable photinitiators include acetophenones (e.g., -substituted haloacetophenones, and diethoxyacetophenone); 2,4-dichloromethyl-1,3,5-triazines; benzoin methyl ether; and o-benzoyl oximino ketone. Examples of suitable sensitizers include p-(dialkylamino)aryl aldehyde; N-alkylindolyidene Check sp; and bis[p-(dialkylamino)benzylidene] ketone. [0035]
Because of the preference for flexible and foldable IOLs, an especially preferred class of macromer monomers is poly-siloxanes endcapped with a termination siloxane moiety that includes a photopolymerizable group. An illustrative representation of such a monomer is [0036]
X—Y—X¹
As described more fully below, adjustable optical implants are those optical implants such as IOLs whose properties can be manipulated or adjusted post implantation by non-invasive measures. In the preferred embodiment, the adjustable implant's contain macromers which are capable of inducing change in the implant when the implant is exposed to an external stimulus. [0037]
wherein Y is a siloxane which may be a monomer, a homopolymer or a copolymer formed from any number of siloxane units, and X and X[0038] ¹may be the same or different and are each independently a terminal siloxane moiety that includes a photopolymerizable group. An illustrative example of Y include
wherein m and n are independently each an integer and R[0039] ¹, R², R³, and R⁴are independently each hydrogen, alkyl (primary, secondary, tertiary, cyclo), aryl, or heteroaryl. In preferred embodiments, R¹, R², R³, and R⁴is a C¹-C¹⁰alkyl or phenyl. Because Macromer monomers with a relatively high aryl content have been found to produce larger changes in the refractive index of the inventive lens, it is generally preferred that at least one R¹, R², R³, and R⁴is an aryl, particularly phenyl. In more preferred embodiments, R¹, R², and R³are the same and are methyl, ethyl or propyl and R⁴is phenyl.
Illustrative examples of X and X[0040] ¹(or X¹and X depending on how the Macromer polymer is depicted) are
Respectively wherein: [0041]
R[0042] ⁵and R⁶are independently each hydrogen, alkyl, aryl, or heteroaryl; and
Z is a photopolymerizable group. [0043]
In preferred embodiments, R[0044] ⁵and R⁶are independently each a C₁-C¹⁰or phenyl and Z is a photopolymerizable group that includes a moiety selected from the group consisting of acrylate, allyloxy, connamoyl, methaacrylate, stibenyl, and vinyl. In more preferred embodiments, R⁵and R⁶is methyl, ethyl, or propyl and Z is a photopolymerizable group that includes an acrylate or methacrylate moiety.
In especially preferred embodiments, an macromer monomer if of the following formula [0045]
wherein X and X[0046] ¹are the same and R¹, R², R³, and R⁴are as defined previously. Illustrative examples of such Macromer monomers include dimethylsiloxane-diphenylsiloxane copolymer endcapped with a vinyl dimethylsilane group; dimethylsiloxane-methylphenylsiloxane copolymer endcapped with a methacryloxypropyl dimethylsilane group; and dimethylsiloxane endcapped with a methacryloxypropyldimethylsilane group. Although any suitable method may be used, a ring-opening reaction of one or more cyclic siloxanes in the presence of triflic acid has been found to be a particularly efficient method of making one class of inventive macromers. Briefly, the method comprises contacting a cyclic siloxane with a compound of the formula
in the presence of triflic acid wherein R[0047] ⁵, R⁶, and Z are as defined previously. The cyclic siloxane may be a cyclic siloxane monomer, homopolymer, or copolymer. Alternatively, more than one cyclic siloxane may be used. For example, a cyclic dimethylsiloxane tetramer and a cyclic methyl-phenylsiloxane trimer are contacted with bis-methacryloxypropyltetramethyldisiloxane in the presence of triflic acid to form a dimethyl-siloxane methyl-phenylsiloxane copolymer that is endcapped with a methacryloxypropyl-dimethylsilane group, an especially preferred macromer.
The adjustable IOLs may be fabricated with any suitable method that results in a first polymer matrix with one or more components which comprise the Macromer dispersed therein, and where the Macromer is capable of stimulus-induced polymerization to form a second polymer matrix. In general, the method for making an inventive IOL is the same as that for making an inventive optical element. In one embodiment, the method comprises: [0048]
mixing a first polymer matrix composition with a Macromer to form a reaction mixture; [0049]
placing the reaction mixture into a mold; [0050]
polymerizing the first polymer matrix composition to form said optical element; and [0051]
removing the optical element from the mold. [0052]
The type of mold that is used will depend on the optical element being made. For example, if the optical element is a prism, then a mold in the shape of a prism is used. Similarly, if the optical element is an intraoccular lens, then an intraoccular lens mold is used and so forth. As described previously, the first polymer matrix composition comprises one or more monomers for forming the first polymer matrix and optionally includes any number of formulation auxiliaries that either modulate the polymerization reaction or improve any property (whether or not related to the optical characteristic) of the optical element. Similarly, the Macromer comprises one or more components that together are capable of stimulus-induced polymerization to form the second polymer matrix. Because flexible and foldable intraoccular lenses generally permit smaller incisions, it is preferred that both the first polymer matrix composition and the Macromer include one or more silicone-based or low T[0053] _gacrylic monomers when the inventive method is used to make IOLs.
Once the adjustable optical element has been formed, it is then implanted in a non-human test subject. Implantation entails removal of the existing lens by phaecoemulsification and extraction of the lens debries. This is followed by implantation of the element using standard surgical procedures. [0054]
After the eye has had sufficient time to heal, (1 to 2 weeks) the eye is then examined for evidence of inflammation. The same time, operability testing can also be conducted. [0055]
Operability testing involves attempting to manipulate the properties of the implant in vivo followed by an evaluation as to whether the desired changes have occurred. [0056]
In the preferred embodiment, this entails exposing at least a portion of the implant to an external stimulus so as to induce a change in the properties of the implant. In one embodiment, ultraviolet light is said to induce photopolymerization of macromers in at least a portion of an adjustable IOL polymerization of the macromers causes change in the shape of the IOL and/or the refractive index of the IOL. The extent of the changes is then evaluated to see if the desired optical properties have been achieved. [0057]
Determination of biocompatibility can be accomplished either in vivo or ex vivo or both. Physical examination of the eye can be used to determine the presence of inflammation and their biocompatibility. In some cases, however, it may be necessary to explant the lens and conduct histopathological studies of the eye tissue to determine biocompatibility. [0058]
The determination of operability requires that at least the adjustment phase be done in vivo followed by examination of the lens in vivo or ex vivo. In vivo examination of the lens can be done using an autoretractometer or a Scheimpflug imaging device to determine change in refraction and/or shape. Alternatively, the lens may be explanted after an ajustment lens has been attempted and the changes in the lens can be determined ex vivo. [0059]

EXAMPLE 1

Sterilized, adjustable IOLs were implanted in albino rabbit eyes. After clinically following the eyes for one week, the rabbits were sacrificed. The extracted eyes were evaluated, placed in familiar and studied histopathologically. There was no evidence of corneal toxicity, anterior segment inflammation or other signs of lens toxicity. [0060]

EXAMPLE 2

A series of adjustable IOLs were prepared for implantation. The IOLs comprised a silicon based polymer matrix with dimethylsiloxane macromer dispersed therein. The safety and operability of the lenses was evaluated in four rabbits. The rabbits were first anesthetized and the existing lens was removed using phaecoemulsification. The IOLs were then implanted into the rabbits. [0061]
The rabbit eyes were exposed to ultraviolet light for 60 to 120 seconds to induce localized polymerization of macromer in the center of the lens. [0062]
The next day, the rabbits were checked physically to determine if any infection develop or if there was any evidence that the lens was not biocompatible. No evidence of incompatibility or infection was noted. [0063]
The lenses were then examined to determine if the desired changes in optical properties had taken place. This was accomplished by explanting the lenses and then evaluating the change in lens power achieved. In this case the power of the lenses increased an average of 0.72 diopters. [0064]

EXAMPLE 3

In this set of experiments, 16 adjustable lens were implanted into albino rabbit eyes. The lenses were adjusted in vivo to diopters of approximately −1.0, −0.5, +1.0 and 2.5 using ultraviolet light. The lenses were then evaluated for biocompatibility and operability by sacrificing the rabbits and explanting the lenses. As shown in FIG. 1, four lenses showed a change in diopters of −1.00,D four had a change in diopter of −0.64D, three had a change in diopter of +0.98D and four had a change of +2.68D. [0065]
Histopathological studies of the eyes showed no inflammation. This indicated good biocompatibility for the lens. [0066]
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. [0067]

Claims

What is claimed is:

1. A method for testing biocompatibility of an optical element containing a refraction modulating composition, comprising the steps of:

a) forming an optical element of a polymer with macromers dispersed therein, wherein the macromers is capable of stimulus-induced polymerization, such that a stimulus causes a desired change of refraction;

b) sterilizing the optical element;

c) implanting the optical element in an eye;

d) extracting the optical element from the eye after a period of time and testing for toxicity.

2. The method of claim 1, and further including the step of:

a) forming the optical element with a refraction modulating composition selected from the group consisting of an acrylate, methacrylate, vinyl, siloxane and phosphazene.

3. The method of claim 1, and further including the step of:

a) forming the optical element of polysiloxane matrix and a refraction modulating composition dispersed therein.

4. The method of claim 1, and further including the step of:

a) exposing at least a portion of the optical element to a stimulus after the step of implanting the optical element, whereby the stimulus induces the polymerization of the refraction modulating composition, such that the stimulus causes a desired change of refraction.

5. The method of claim 4, and further including the step of:

a) waiting an interval of time after the step of exposing, and

b) re-exposing the portion of the optical element to the stimulus to induce the further polymerization of the refraction modulation composition which the portion, such that the stimulus produces a desired change of refraction.

6. The method of claim 4, and further including the step of:

a) the step of exposing includes exposing at least a portion of the optical element to stimulus from a light source.

7. The method of claim 4, and further including the steps of:

a) implanting a plurality of optical elements in a like number of rabbit eyes;

b) exposing at least a portion of a number of the optical elements to a stimulus after the step of implanting the optical elements, whereby the stimulus induces the polymerization of the refraction modulating composition, such that the stimulus causes a desired change of refraction; and

c) explanting the optical elements from the rabbit eyes and testing for toxicity.

8. The method of claim 7, and further including the steps of:

a) maintaining at least some of the optical elements in the rabbit eyes without exposing the optical elements to a stimulus; and

b) explanting the optical elements from the rabbit eyes and testing for toxicity.

9. A method of evaluating an adjustable optical implant comprising:

a) Inserting an adjustable optical implant into a test subject.

b) Adjusting the optical properties of said implant in vivo; and

c) Evaluating the change in optical properties of the implant.

10. The method of claim 9 wherein the implant comprises macromers capable of inducing changes in the optical properties of the implant when the macromers are exposed to an external stimulus.

11. The method of claim 9 wherein the adjusting of the optical properties of the implant is accomplished by exposing at least a portion of said implant to an external stimulus.

12. The method of claim 10 wherein the external stimulus is light.

13. The method of claim 10 wherein the external stimulus is ultraviolet light.

14. The method of claim 10 wherein the implant is an intraoccular lens.

15. A method for evaluating an adjustable optical implant comprising

a) Inserting an adjustable optical implant in a test subject;

b) Adjusting the optical properties of the implant in vivo; and

c) Evaluating the changes in optical properties and the biocompatability of the implant.

16. The method of claim 15 wherein said optical implant comprises macromers which can induce changes in the optical properties of the implant upon exposure to an external stimulus.

17. The method of claim 15 wherein said adjusting step is accomplished by exposing at least a portion of said implant to an external stimulus.

18. The method of claim 17 wherein said external stimulus is light.

19. The method of claim 18 wherein said light is ultraviolet light.

20. The method of claim 15 further comprising the step of evaluating the biocompatibility of the implant.

21. The method of claim 15 wherein the implant is an intraoccular lens.

22. A method of evaluating an adjustable optical implant comprising:

a) Inserting an adjustable optical implant into a test subject.

b) Adjusting the optical properties of said implant in vivo; and

c) Evaluating the change in optical properties in the implant in vivo.

23. The method of claim 22 wherein the adjusting of the optical properties of the implant is accomplished by exposing at least a portion of said implant to an external stimulus.

24. The method of claim 23 wherein the external stimulus is light.

25. The method of claim 23 wherein the external stimulus is ultraviolet light.

26. The method of claim 22 wherein the implant is an intraoccular lens.