The present invention relates to systems and methods for treating contact lenses, and more particularly relates to such systems and methods involving disinfection of contact lenses. Currently, a number of conventional systems and methods are available for disinfecting contact lenses between wearing periods. These systems and methods can be characterized as either "hot" or "cold", depending upon whether heat is employed to disinfect the lens. Cold contact lens disinfection systems typically employ chemical disinfectants, such as hydrogen peroxide, to disinfect the lens. These chemical disinfectants act as bactericides and fungicides, which kill bacteria or fungi present on the contact lens. Cold disinfection systems and methods typically involve treatment of the contact lens with an aqueous solution of a chemical disinfectant until the lens has been effectively sterilized. Since the chemical disinfectant can be a severe eye irritant, the lens is thoroughly rinsed, e.g., with saline solution, following disinfection in order to remove excess disinfectant prior to returning the lens to the eye. Rinsing of the lens to remove excess disinfectant is not, however, a fully satisfactory procedure because, for example, of incomplete removal of the disinfectant and the possibility of recontaminating the lens, e.g., with a user's finger, during the rinsing step.

Another consideration regarding the use of cold disinfection systems involves the removal of deposit accumulations or debris on the lens, such as proteins and lipids secreted by the eye. Removal of debris from the

lens is important in caring for the lens, for example, to enhance the comfort of wearing the lens .

In order to simplify contact lens disinfection and cleaning, a number of methods have been proposed which neutralize the disinfectant in situ while it is in contact with a lens so that the need for a subsequent rinse step is reduced or eliminated. For example, Perlaky U.S. Patent No. 5,089,240 proposes a sterilization system that employs two catalytic elements for decomposing hydrogen peroxide to safe levels in a reservoir containing a contact lens. Another approach to sterilizing contact lenses is proposed in Schafer et al U.S. Patent No. 5,011,661, wherein a tablet containing an enzymatic peroxide neutralizing agent, such as catalase, and a release retarding agent is placed in contact with an aqueous hydrogen peroxide solution and the contact lens. A further method for sterilizing a contact lens is proposed by Kay U.S. Patent No. 4,826,658, which suggests placing the contact lens in a vial coated on its interior wall with an immobilized enzyme, e.g., catalase, which catalytically decomposes hydrogen peroxide. However, the user of such systems is only passively involved. It would be advantageous if the user more actively participated in the disinfection procedure so as to assure himself/herself that the disinfection is complete and that the contact lens is safe to wear. Also, the systems described in these patents do not remove protein and lipid deposits from the lens.

Smith et al U.S. Patent No. 5,088,146 proposes a foam-lined pouch for cleaning deposits from a contact lens inserted therein whereby the foam surface is rubbed against the lens surface in the presence of a cleaning solution. However, this patent does not describe the use of such a pouch with a disinfectant, let alone how to free the lens of the disinfectant.

A disposable contact lens disinfecting package is proposed in Ajello U.S. Patent No. 5,054,610. This package has separate containers for solutions used to sterilize and neutralize or rinse contact lenses. However, this package requires physical transfer of the lens from the sterilization solution to the neutralization/rinse solution. Such transfer can be difficult to perform and risks recontamination of the lens. Despite the above-described approaches to disinfecting or cleaning contact lenses, there continues to be a need for systems and methods of disinfecting, and preferably cleaning, contact lenses in which the user (lens wearer) is a more active participant. Such more active user participation would advantageously increase user compliance so that contact lenses would be more effectively and/or frequently disinfected and cleaned and, ultimately, the ocular health of the lens wearer would be benefitted. Summary of the Invention

New systems and methods for disinfecting a contact lens have been discovered. The present systems and methods allow the user to directly control the disinfecting, and preferably cleaning, of his/her contact lenses. Such direct control advantageously leads to enhanced user compliance and, ultimately, to enhanced ocular health. The present systems are preferably disposable for increased convenience and cleanliness and to avoid contamination of contact lenses . The systems of the present invention can be relatively easily and inexpensively produced. The present methods are straightforward and easy to practice. Using the present invention, contact lenses are effectively disinfected, and preferably cleaned, and, if desired, the residual disinfectant is effectively destroyed, all in a single

step, that is without moving the lens from one solution to another or from one container to another.

In one broad aspect of the invention, disposable contact lens disinfectant systems are provided. Such systems comprise a matrix material, preferably a polymeric and/or hydrophilic matrix material, adapted to hold a contact lens; and a contact lens disinfecting amount of a disinfectant component located in the matrix material, preferably combined with or as a component of an opthalmically acceptable liquid aqueous medium in the matrix material . The matrix material is preferably adapted to be manually rubbed on or against the surface of the contact lens held by the matrix material to thereby facilitate the disinfecting of the contact lens. This embodiment allows the user to have effective and direct control of the lens disinfecting system so that enhanced user compliance, and ultimately enhanced ocular health, is obtained. In this embodiment of the present invention the disinfectant component may be either an oxidative disinfectant component or a substantially non-oxidative disinfectant component.

In another broad aspect of the invention, contact lens disinfecting systems are provided which comprise: (i) a matrix material adapted to contact a surface of the contact lens when the lens is placed in contact with the matrix material; . (ii) an amount of an oxidative disinfectant component effective to disinfect the lens; and (iii) a disinfectant destroying component immobilized on a portion of the matrix material and present in an amount effective to destroy substantially all of the oxidative disinfectant used to disinfect the lens. Such unitary lens care systems can be used to oxidatively disinfect a contact lens as well as to destroy the disinfectant sufficiently to avoid eye irritation. Since the disinfectant destroying component remains immobilized

on the matrix material, it is not itself an additional source of contamination or eye irritation. Moreover, ^• since the user places the matrix material in direct contact with the lens to effect disinfection, and preferably destruction of residual disinfectant, the user advantageously has a substantial degree of control over the disinfection process.

In a preferred aspect of the invention, the disinfectant destroying component of the instant lens care system is immobilized on a first portion of the matrix material and the oxidative disinfectant is contained within a second portion of the matrix material. The oxidative disinfectant may be present in the matrix material as an aqueous solution. When the oxidative disinfectant is so contained within the matrix material, the system preferably further comprises a barrier adapted to separate the oxidative disinfectant from the disinfectant destroying component until a lens is to be disinfected. The barrier can be compromised, for example, broken, relocated, removed or otherwise functionally negated, to permit the oxidative disinfectant to contact the disinfectant destroying component, and preferably the contact lens to be disinfected.

The present disinfection systems often employ an oxidative disinfectant component, that is a component which utilizes chemical oxidation to kill microorganisms contaminating a contact lens. Any suitable oxidative disinfectant component may be employed, provided it functions as described herein and has no undue detrimental effect on the contact lens being disinfected or on the wearer of the disinfected contact lens. Particularly useful oxidative disinfectant components include hydrogen peroxide, chlorine dioxide, alkali metal peroxy salts, for example, the potassium salt of peroxymonosulfate, and

mixtures thereof. Hydrogen peroxide is a particularly useful oxidative disinfectant component.

Preferred disinfectant destroying components for use in the present systems include reducing agents, enzymes, and mixtures thereof. More preferably the disinfectant destroying component is catalase.

In another aspect of the invention, the disinfection systems further comprise a barrier adapted to separate the oxidative disinfectant from the disinfectant destroying component, even when the oxidative disinfectant is not initially present within the matrix material . The barrier is compromisable to permit the oxidative disinfectant to contact a lens to be disinfected and to contact the disinfectant destroying component to destroy residual disinfectant. Thus, for example, the oxidative disinfectant can be contained in a compartment adjacent the matrix material of the present system with an intervening barrier between the compartment and the matrix until a lens is to be disinfected. An example of such a system is a dual pouch or pocket system as illustrated herein.

A further aspect of the invention involves methods for disinfecting a contact lens employing a lens care system as described herein. Such methods comprise contacting the lens with a disinfectant component in a liquid aqueous medium in the presence of a matrix material, preferably a hydrophilic matrix material, containing at least a portion of the liquid aqueous medium. Preferably, the matrix material is manually squeezed during this contacting, for example, to facilitate intimate contacting between the disinfectant component and the contact lens . In the event that an oxidative disinfectant component is employed, the matrix material preferably has a disinfectant destroying component immobilized thereon. The disinfectant

destroying component destroys the oxidative disinfectant, as by decomposing, neutralizing, deactivating, etc., the disinfectant, during or after the time the lens is being disinfected. Accordingly, the present invention affords several advantages over previously proposed systems. For example, the present invention permits disinfecting a contact lens in a single step, without the need for a subsequent rinse step. In addition, since the user is actively involved in the lens disinfecting, for example, by using the present matrix material to manually rub the lens, the user has more direct control of the disinfecting and feels more comfortable that his/her lens has been effectively disinfected. This increased "user control" also leads to increased user compliance and, ultimately, increased ocular health. Further, mechanical damage to the lens is reduced because the present systems reduce the need for direct finger rubbing of the lens. Other advantages will be readily apparent to the skilled practitioner and by reference to the description of the invention presented hereinbelow.

Description of the Drawings

Fig. 1A is a perspective view of one embodiment of the system of the present invention which shows the system in a first configuration prior to use.

Fig. IB is a perspective view of the embodiment shown in Fig. 1A showing the system opening up to permit placement of a contact lens therein. Fig. 1C is a perspective view of the embodiment shown in Fig. 1A which illustrates a second configuration of the system when it is in use.

Fig. ID depicts a cross-sectional view of the system shown in Fig. 1C taken generally along line ID-ID.

Fig. IE is a cross-sectional view of the system shown in Fig. 1A taken generally along line IE-IE.

Fig. IF is a cross-sectional view of the system shown in Fig. 1C taken generally along line 1F-1F. Fig. 2A presents a plan view of another embodiment of the present system.

Fig. 2B is a cross-sectional view of the embodiment shown in Fig. 2A.

Fig. 2C is a partial cross-sectional view of the pouch shown in Fig. 2B which illustrates the pouch swelling after the liquid medium is introduced and being opened to expose the contact lens.

Detailed Description of the Invention The present invention is applicable to conventional contact lenses, such as hard contact lenses, rigid gas permeable (RGP) contact lenses and soft contact lenses. This invention is particularly useful in treating soft contact lenses. The lenses may be made of any suitable material or combination of materials not substantially deleteriously affected by the components included in the present systems and used in practicing the present methods, which are described more fully herein. Matrix Material The disinfection systems of the present invention comprise a matrix material, for example, a solid matrix material, preferably a polymeric matrix material, which is adapted to contact a surface of a contact lens, for example, to hold the contact lens. In one embodiment of the invention, the matrix material defines a cavity or space, for example, which conforms to a contour, such as to a surface, of the contact lens placed in contact therewith. The matrix material may be configured so as to form two cavities, for both of the user's contact lenses, for the convenience of the user. Any suitable matrix

material can be employed provided that it functions as described herein and has no undue detrimental effect on the contact lens being treated or on the wearer of the treated lens. Preferred polymeric matrix materials include materials selected from silicone polymers, polyurethanes, polyesters, polystyrene, polyolefins, polyvinylchloride, cross-linked polyvinyl pyrrolidone, hydroxyalkyl acrylate polymers, hydroxyalkyl methacrylate polymers, collagen, hydrogel-forming polymers, mixtures thereof and the like.

The matrix material is preferably hydrophilic, that is, it chemically absorbs, adsorbs and/or binds water, and holds water that it (in its dry state) is brought into contact with. The hydrophilic matrix material is preferably composed of a hydrophilic polymeric component, more preferably selected from hydrophilic polyurethane components.

The matrix material can assume a number of different configurations or physical forms. Preferably, the matrix material is sufficiently compressible or deformable and soft so as not to damage a contact lens with which the matrix material is brought into contact. The matrix material is preferred to have sufficient water carrying ability so that the material can contain sufficient aqueous medium containing a contact lens disinfecting amount of a disinfectant component, for example, an oxidative disinfectant component. The matrix material is more preferably in the form of a polymeric film or foam. In addition, it is preferred that the matrix material employed is hydrophilic and that the amount of liquid aqueous medium employed is effectively completely absorbed or otherwise taken up by the matrix material so that substantially no free liquid phase (that is no liquid other than that combined with the matrix material) is apparent. This feature greatly increases the convenience

of using the present systems since the user can remove the disinfected lens from the matrix material (after disinfection) without risking spilling or even encountering a separate liquid phase. Thus, after disinfecting, the lens is removed from the matrix material and placed in the eye for comfortable and safe wear while the used matrix material (including the combined or entrapped liquid aqueous medium) is conveniently disposed of. When a hydrophilic polyurethane component is employed it is preferably derived from one or more isocyanate- capped polyalkylene polyols. Such polyols, referred to hereinafter as polyol prepolymers, can be produced using conventional techniques. See, for example, Wood et al . U.S. Patent No. 4,137,200, which is incorporated in its entirety herein by reference.

Briefly, such polyol prepolymers are preferably prepared by capping polyoxyalkylene, preferably polyoxyethylene, glycols having a reactive functionality equal to 2 with a molar excess of a diisocyanate which leads to an isocyanate-capped polyurethane product (A) having an isocynate functionality of 2. A polyol, such as pentaerythritol, having a reactive functionality equal to 4 is reacted with a large molar excess of a diisocynate to form an isocynate-capped polyurethane intermediate product (B) having an isocyanate-capped functionality of 4. Other monomeric or polymeric polyisocyanate cross-linking agents may be substituted for the tetraisocyanate product (B) . Tolylene-2,4, 6-triisocyanate, having a reactive functionality of 3, is an example of a simple monomeric triisocyanate which may be usefully employed to achieve the same objective of imparting to the system an average isocyanate functionality greater than 2. By blending the two isocyanate-capped products thus prepared (products (A) and (B) ) , in various molar proportions, the resulting

product mixture has an average isocyanate functionality greater than 2. This product mixture is then combined with an aqueous reactant to form a hydrophilic cross- linked polyurethane foam. If, as is preferred, catalase or the like enzyme is to be employed as a disinfectant (hydrogen peroxide) destroying component immobilized on the polyurethane matrix material, such material can be formed as follows. The product mixture noted above is combined with an aqueous reactant containing an enzyme, such as catalase, to form a hydrophilic cross-linked polyurethane foam including covalently bonded enzyme, for. example, catalase, component.

Care should be taken so that the capped product has a reaction functionality greater than 2 even after considering that the amine or amino group of the enzyme reacts with an isocyano group on the capped product. Alternatively, the capped product and/or aqueous reactant may contain a suitable cross-linking agent, if desired, in which case the capped product may have a functionality approximating 2.

The amount of cross-linking provided for in the hydrophilic matrix material may be controlled so as to control the rate of diffusion of the liquid aqueous medium containing oxidative disinfectant component into the matrix material. In addition, the surface area of the hydrophilic matrix material may be controlled, for example, by controlling the materials present and/or the conditions employed during the production of the hydrophilic matrix material. If a hydrophilic polyurethane component, such as is described above, is employed, its surface area can be controlled by controlling the amount and/or type of surfactant component included during foaming. In general, the larger the surface area of the matrix material the higher the rate of oxidative disinfectant component destruction. The

diffusion controlling feature and/or the surface area controlling feature of the present invention can be used to control the rate at which the disinfectant destroying component destroys the oxidative disinfectant present in the liquid aqueous medium, so that a contact lens present in the oxidative disinfectant-containing medium can be effectively disinfected before the oxidative disinfectant is effectively destroyed. At the same time, however, the rate of diffusion and the surface area of the matrix material should be sufficiently high to result in substantially complete destruction of the residual oxidative disinfectant in the aqueous medium in a reasonable time, for example, in about 4 hours or less, preferably in about 2 hours or less and more preferably in about 5 minutes to about 30 minutes, after the oxidative disinfectant-containing medium is introduced to, or initially contacted with, the disinfectant destroying component-containing matrix.

In one embodiment, the matrix material in accordance with the invention is formed in a mold using conventional techniques. When a polymeric foam is used as the matrix material, it is preferably formed in the mold. The foam can be formed by combining a suitable monomeric component or mixture of monomeric components with a suitable medium, for example, an aqueous medium, optionally containing one or more other materials therein, and passing the combination to a mold where the foam is formed. Suitable molds can be formed of plastics such as polypropylene, polyethylene, or polyfluorohydrocarbon-coated metal. Exemplary other materials which may be contained in the medium and/or in the combination and/or in the matrix material include an effective amount of one or more of disinfectant destroying components, contact lens cleaning components, surfactants, dispersion agents, chelating agents such as the disodium salt of ethylene diamine

tetraacetic acid (EDTA) , organic and inorganic salts (for example, tonicity adjustors) , buffer components, (for ^• example, carbonates, bicarbonates, acetates, citrates, phosphates, borates, and the like), wetting components, lubricating components, conditioning components, alcohols, biopolymers, color indicators of hydrogen peroxide decomposition, and the like materials useful in treating contact lenses and/or in providing one or more desired properties to the matrix material . The desired softness and porosity characteristics of the matrix material can be obtained by appropriate selection of dispersion agent .

Whichever matrix material is selected for use in the present invention, it should be such so as not to scratch the contact lens being treated. A soft hydrophilic foam having sponge-like characteristics is preferably employed. Accordingly, a user can disinfect a contact lens numerous times in accordance with the present invention without the lens being detrimentally affected.

Disinfectant Component

The contact lens care systems of the present invention preferably include a disinfectant component, for example, an oxidative disinfectant component or a substantially non-oxidative disinfectant component. Oxidative disinfectant components act to reduce the microbial load on a' contact lens by oxidatively attacking the microbes. The oxidative disinfectant suitable for use in the present invention is preferably selected from hydrogen peroxide, chlorine dioxide, metal, such as alkali metal, peroxy salts, such as peroxymonosulfate salts, and mixtures thereof, and is more preferably hydrogen peroxide.

As used herein, substantially non-oxidative disinfectant components include effectively non-oxidative organic chemicals which derive their antimicrobial

activity through a chemical or physiochemical interaction with the microbes or microorganisms. Suitable non- oxidative disinfectant components are those generally employed in ophthalmic applications and include, but are not limited to, quaternary ammonium salts used in ophthalmic applications such as poly[dimethylimino-2- butene-1, 4-diyl] chloride, alpha- [4-tris (2-hydroxyethyl) ammonium] -dichloride (chemical registry number 75345-27-6, available under the trademark polyquarternium 1 ^® from ONYX Corporation) , benzalkonium halides, and biguanides such as salts of alexidine, alexidine-free base, salts of chlorhexidine, hexamethylene biguanides and their polymers, antimicrobial polypeptides, and the like and mixtures thereof. A particularly useful substantially non-oxidative disinfectant component is selected from tromethamine (2-amino-2-hydroxymethyl-l, 3 propanediol) and its ophthamalically acceptable salts alone or in combination with a microbicide component selected from polyhexamethylenebiguanide (PHMB) , N-alkyl-2-pyrrolidone, chlorhexidine, polyquaternium-1, hexetidine, bronopol, alexidine, very low concentrations of peroxide, ophthalmically acceptable salts thereof and mixtures thereof .

The salts of alexidine and chlorhexidine can be either organic or inorganic and are typically disinfecting gluconates, nitrates, acetates, phosphates, sulphates, halides and the like. Generally, the hexamethylene biguanide polymers, also referred to as polyaminopropyl biguanide (PAPB) , have molecular weights of up to about 100,000. Such compounds are known and are disclosed in U.S. Patent No. 4,758,595.

The substantially non-oxidative disinfectant components useful in the present invention are preferably present in the liquid aqueous medium in concentrations in the range of about 0.00001% to about 2% (w/v) .

More preferably the substantially non-oxidative disinfectant component is present in the liquid aqueous medium at an ophthalmically acceptable or safe concentration such that the user can remove the disinfected lens from the liquid aqueous medium/matrix material combination and thereafter directly place the lens in the eye for safe and comfortable wear.

When a contact lens- is desired to be disinfected, an amount of disinfectant effective to disinfect the lens is used. Preferably, such an effective amount of the disinfectant reduces the microbial burden on the contact lens by one log order in three hours. More preferably, an effective amount of the disinfectant reduces the microbial load by one log order in one hour. Particularly preferred are disinfectant concentrations that reduce the microbial load by one log order in ten minutes or less.

The disinfectant of the present invention is preferably provided in a liquid aqueous medium. One liquid aqueous medium useful to disinfect a contact lens contains a disinfecting amount of hydrogen peroxide and has a pH of less than about 5, typically in the range of 4 to 5. Relatively mild hydrogen peroxide containing liquid aqueous media preferably contain about 0.5% to about 6% of hydrogen peroxide. The actual concentration of disinfectant selected depends, for example, on the effectiveness of the specific disinfectant in reducing the microbial load on the contact lens. Liquid Medium

The liquid media used are selected to have no substantial deleterious effect on the lens being treated, or on the wearer of the treated lens. The liquid media are constituted to permit, and even facilitate, the instant lens treatment or treatments. The liquid media are preferably aqueous-based and more preferably (exclusive of the oxidative disinfectant component which

may be present) are substantially isotonic and/or are ophthalmically acceptable liquid aqueous media. A material is said to be "ophthalmically acceptable" when it is compatible with ocular tissue, that is causes no significant or undue detrimental effect when brought into contact with ocular tissue. The liquid media preferably include an effective amount of a tonicity adjusting component to provide the liquid media with the desired tonicity. The liquid aqueous media of the present invention preferably include a buffer component which is present in an amount effective to maintain the pH of the medium in the desired range. This buffer component may be present in the liquid medium and/or may be introduced into the liquid medium. Among the suitable buffer components or buffering agents that may be employed are those conventionally used in contact lens care products. The buffer salts are preferably alkali metal, alkaline earth metal, or ammonium salts. Particularly useful media are those derived from saline, e.g., a conventional saline solution, or buffered saline solution. In addition, the liquid aqueous media may include one or more other materials, for example, as described elsewhere herein, in amounts effective to treat the contact lens (for example, provide a beneficial property to the contact lens) contacted with such media.

During the disinfecting step it is preferred that the liquid aqueous medium has a pH in the range of about 2 or 3 to about 9. During the time in which the residual oxidative disinfectant is being destroyed, the pH of the liquid medium is preferably about 3 or higher, more preferably about 6 to 8. Disinfectant Destroying Component

The present invention employs a disinfectant destroying component immobilized on the matrix material when an oxidative disinfectant component is employed. Any

agent effective in destroying the oxidative disinfectant used can ^' be employed as the disinfectant destroying component. Such a disinfectant destroying component should be used in an amount effective to destroy substantially all the oxidative disinfectant present in the aqueous medium during a reasonable period of time. The disinfectant destroying component employed should have no undue detrimental effect on the contact lens or on a wearer's eye when the lens is placed therein. Particularly useful disinfectant destroying components include reducing agents, enzymes, such as peroxidases, for example, catalase, and mixtures thereof.

Exemplary reducing agents include those effective to chemically reduce hydrogen peroxide. Such reducing agents include thiosulfates, thiourea, sulfites, thioglycerol, N- acetylcysteine, formates, ascorbic acid, isoascorbic acid, glyoxylic acid and mixtures thereof. Especially preferred are alkali metal salts of the above compounds. Peroxidases, that is enzymes that promote the decomposition of hydrogen peroxide, can also be employed. A particularly preferred peroxidase is catalase. When catalase is employed as a disinfectant destroying component, a useful amount of catalase for a liquid aqueous medium containing about 3% (w/v) hydrogen peroxide is preferably about 10 to about 1000, more preferably about 20 to about 800, international units of catalase activity per milliliter of liquid medium.

A number of methods for immobilizing the disinfectant destroying component on the matrix are contemplated, such as by physical entrapment, covalent bonding and the like. In one useful embodiment in which the disinfectant destroying component is covalently bonded to the matrix material, a disinfectant destroying component precursor, e.g., catalase, is combined with the matrix precursor, for example, the isocyanate capped product mixture noted

above, under effective conditions to provide a covalently bonded disinfectant destroying component. When the -capped product mixture noted above is used in combination with catalase and a liquid aqueous medium, this procedure is effective to cause reaction between the amino groups of the catalase and isocyano groups of the product mixture, thereby covalently bonding the catalase to the polyurethane. Cleaning Enzymes A cleaning enzyme component can be provided, for example, within the matrix material, in order to remove debris from the contact lens. Types of debris which may be deposited on the lens include proteins, lipids, and carbohydrate-based or mucin-based debris. One or more types of debris may be present on a given lens.

The cleaning enzyme component employed may be selected from peroxide-active enzymes conventionally employed in the enzymatic cleaning of contact lenses . Among the preferred enzymes are proteases, lipases, and the like. Exemplary enzymes are described by Huth et al . U.S. Patent No. 32,672 RE and Karageozian et al . U.S. Patent No. 3,910,296, which disclosures are incorporated herein by reference.

Preferred proteolytic enzymes are those substantially free of sulfhydryl groups or disύlfide bonds, the presence of which may react with active oxygen of the oxidative disinfectant, rendering the enzyme inactive. Metalloproteases, enzymes which contain a divalent metal ion, may also be used. Yet a more preferred group of proteolytic enzymes are the serine proteases, such as those derived from Bacillus and Streptomyces bacteria and Asperigillus molds . Of this class of enzymes, still more preferred enzymes are those derived from alkaline proteases, generically referred to as subtilisin enzymes.

Other enzymes preferred for this application include pancreatin, trypsin, collaginase, keratinase, carboxylase, aminopeptidase, elastase, and aspergillopeptidase A and B, pronase E (from S. griseus) and dispase (from Bacillus polvmyxa) .

When an enzyme is employed to remove debris in the practice of this invention, the enzyme should be used in an amount effective to remove in a reasonable time substantially all of at least one type of lens debris due to normal wear. The very small group of wearers who may at one time or another have a significantly increased rate of debris accretion is not included within the group of normal wearers.

The amount of debris-removing enzyme required to effectively clean the contact lens depends on several factors, such as the inherent activity of the enzyme which activity likely declines over time. A working solution which contains an enzyme should have sufficient enzyme to provide about 0.001 to about 3 Anson units of activity, preferably about 0.01 to about 1 Anson units, per single lens treatment. However, higher or lower amounts may be used. Moreover, since enzyme activity is pH dependent, the preferred pH range for an enzyme can be determined by the skilled practitioner. When a debris-removing enzyme is employed with the present invention, the enzyme is preferably immobilized on the matrix material of the invention, for example, by physical entrapment in the matrix material. The cleaning enzyme component may be provided as a component of a liquid medium in contact with the matrix and contact lens. Method of Use

Methods for disinfecting a contact lens are within the scope of the present invention. Such methods comprise contacting the lens with a disinfectant component, preferably in a liquid aqueous medium in the presence of

a matrix material, preferably a hydrophilic matrix material, containing at least a portion of the liquid aqueous medium. If an oxidative disinfectant component is employed, the matrix material preferably has a disinfectant destroying component immobilized on it. An effective amount of a cleaning enzyme component may also be present . The method can further include manipulating the matrix material, preferably by manually squeezing the matrix material and/or by manually rubbing the matrix material against the contact lens, for example, to facilitate disinfecting and/or in order to dislodge debris from the contact lens. Once a lens has been disinfected, in accordance with the present invention, it may be placed directly in the wearer's eye for safe and comfortable wear. Alternatively, the disinfected, and preferably cleaned, lens may be rinsed by another aqueous medium which does not contain an oxidative disinfectant or cleaning enzyme prior to a wearer placing the lens in the eye. Preferably, an oxidative disinfectant of the invention is combined or comes in contact with the matrix material when lens disinfecting occurs.

In order to delay the decomposition of oxidative disinfectant by the disinfectant destroying component it is preferred that the disinfectant destroying component not be effectively exposed to the oxidative disinfectant until the lens has been contacted with the liquid medium for a sufficient time to disinfect the lens. A sufficient disinfecting time is preferably in the range of about 1 minute to about 4 hours, more preferably in the range of about 5 minutes to about 30 minutes or about 1 hour. It is also preferred that substantially all of the residual oxidative disinfectant in the liquid medium be destroyed in less than about 3 hours or about 4 hours after the disinfectant destroying component is initially exposed to the oxidative disinfectant.

The disinfecting contacting step preferably occurs using a quantity, e.g. about 1.ml or abou -5 ml to about 15 ml, of liquid medium at a temperature to maintain the medium substantially liquid. It is preferred that the contacting temperature is in the range of about 0°C to about 100°C, and more preferably in the range of about 10°C to about 60°C. Contacting at or about ambient temperature is particularly convenient and useful . The contacting preferably occurs for a time to effectively disinfect the lens being treated and, if an oxidative disinfectant component is used, to effectively destroy all the oxidative disinfectant originally present.

The following non-limiting examples illustrate certain aspects of the present invention. EXAMPLES 1 AND 2

A prepolymer derived from polyoxyethylene glycol, trimethylolpropane and toluene diisocyanate sold by W.R. Grace and Co. under the trademark Hypol is selected. This prepolymer is combined with an aqueous mixture containing water, a conventional ethylene oxide/propylene oxide block copolymer surface active agent (sold by BASF under the trademark Pluronic F-127) and catalase. This combination is allowed to foam at room temperature into articles of various shapes. The hydrophilic polyurethane foam prepared from this combination exhibits good physical properties.

In one run, identified as Form A, the foam is formed in a mold to produce a unitary pouch which conveniently fits inside and is adhesively secured to a preformed pouch-shaped, water impermeable, thermoplastic polymeric sheath. This pouch includes about 1000 international units of catalase activity in the form of a covalently bonded catalase component.

In another run, identified as Form B, the foam is cast in the form of a plate having two wells which are

shaped to contain contact lenses. This plate includes about 750 international units of catalase activity in the form of a covalently bonded catalase component. In Form B, a second polyurethane foam shaped to mirror the first, can similarly be formed (without catalase) to provide a reservoir for an oxidative disinfectant solution.

EXAMPLE 3 Sealable Case Embodiment

Referring to Fig. 1A, one embodiment of the invention is illustrated. Form B, as described in Examples 1 and 2, may be used in this embodiment. Sealable case 100 is formed from top sheet 102, back sheet 104, and bottom sheet 106. Hydrophilic foam pad 108 is affixed to the lower side of sheet 102 and hydrophilic foam pad 110 is affixed to the top side of sheet 106. Together sheets 102, 104, and 106 form a holder for the matrix provided therein. Barrier sheet 112 is positioned between foam pads 108 and 110. Barrier sheet 112 is joined to top sheet 102 by front sheet 114. Placement of barrier sheet 112 between pads 108 and 110 is facilitated by fold lines 116 and 118. When case 100 is not in use, as when it is being stored, flap 120, which is affixed to bottom sheet 106, is engaged with top sheet 102 by a fold along line 122. A cross-sectional view of sealable case 100 is presented in Fig. IE. This view shows the case latching mechanism more clearly, whereby flap 120 engages top sheet 102. Thus, latch 124 protrudes through opening 126 in top sheet 102 to hold the top and bottom regions of the case together. Groove 128 is provided in front sheet 114 to permit engaging latch 124 with the front sheet when barrier layer 112 is folded outside the case.

Pads 108 and 110 are each formed of hydrophilic polyurethane foams having an internal cellular structure. The internal void space of pad 108 is filled with about

2 ml of a substantially isotonic (when the hydrogen peroxide is destroyed) aqueous solution containing ^' 3% • of . (w/v) hydrogen peroxide. The matrix of pad 110, which also is formed of hydrophilic polyurethane foam, includes a covalently bonded catalase component. Barrier sheet 112 is water-impermeable and separates pads 108 and 110 until a contact lens is to be disinfected, whereupon barrier sheet 112 is moved from between pads 108 and 110.

Another view of sealable case 100 is presented in Fig. IB. In this perspective, barrier layer 112 is rotated up from its previous position between foam pads 108 and 110 to permit placement of a contact lens between the foam pads. Thus, contact lens wells 130 and 132, each contoured to receive a contact lens, are revealed in foam pad 110. The view shown in Fig. IB also shows groove 128 in top sheet 114 which permits attachment of flap 120 thereto, when the case is desired to be sealed with a contact lens within.

Fig. IC shows sealable case 100 in a fully sealed configuration as when a contact lens is placed inside. Thus, barrier layer 112 and front sheet 114 are folded on top of top sheet 102. Flap 120 engages front sheet 114 to hold the case in a sealed configuration.

Two cross-sectional views of sealable case 100 in the configuration shown in Fig. IC are shown in Fig. ID and Fig. IF. Fig. ID' is taken along line ID-ID and shows wells 130 and 132 formed in foam layer 110. Bulges 134 and 136 formed in foam pad 108 protrude into wells 130 and 132, respectively, in order to press against a contact lens provided therebetween. A contact lens 140 is shown as described in well 130 between foam pads 108 and 110.

Finally, Fig. IF shows the cross-sectional view of sealable case 100 taken along line 1F-1F. Thus, latch 124 of flap 120 protrudes through groove 128 in barrier layer

112 in order to seal the case with the barrier layer no longer located between foam pads 108 and 110.

When it is desired to disinfect a pair of contact lenses, sealable case 100 is placed in the configuration shown in Fig. IB, and the contact lenses to be disinfected are placed in wells 130 and 132. Sealable case 100 is then placed in the configuration shown in Fig. IC. This configuration is maintained for 2 hours. At the beginning, and again at the end, of this period of time, the user manually presses top sheet 102 and bottom sheet

106 together to insure intimate contact between the foam pads 108 and 110 and the contact lenses in wells 130 and

132. After this period of time, sealable case 100 is opened and the lenses are removed and placed directly into the user's eyes for safe and comfortable wear. It is found that the lenses are disinfected and that all of the hydrogen peroxide originally present is destroyed.

EXAMPLE 4 Pouch Embodiment Referring to Fig. 2A, another embodiment of the present invention is depicted. Form A, as described in Examples 1 and 2, may be used in the embodiment. An assembly of attached (but detachable) packages 200 is shown. An individual package 200 can be separated from the assembly by tearing along the perforated border between the packages. Each package 200 comprises an aqueous medium-containing pack 202 and a pouch 204 including water impermeable sidewalls 220 and 221. Secured to sidewalls 220 and 221 are individual hydrophilic polyurethane matrix pads 222 and 223, respectively. Matrix pads 222 and 223 are sized and adapted to accommodate and hold a contact lens therebetween. The liquid aqueous medium of pack 202 is about 4 ml in total volume, is substantially isotonic and ophthalmically acceptable (not considering the hydrogen

peroxide) and contains 3% (w/v) of hydrogen peroxide. Pouch 204 further contains catalase covalently bonded to the hydrophilic polyurethane matrix pads 222 and 223. Package 200 is preferably formed from two continuous sheets of a thermoseal plastic material. The border 206 around pack 202 and pouch 204 is sealed, e.g., thermally or by crimping, so as to afford a leak-proof seal around the liquid-containing regions of pack 202 and pouch 204. As shown is Figs. 2A and 2B, a portion 207 of the border surrounding pouch 204 includes two sheets 209 and 211 which are secured together by joining two pair 213 and 215 of mutually engageable elongated tongues and elongated grooves. By separating (disengaging) or joining (engaging) these tongues and grooves, pouch 204 can be opened or closed, as desired, along border portion 207. Barrier segment 208 separates the liquid aqueous medium contents of pack 202 from the matrix pads 222 and 223 of pouch 204. Barrier segment 208 includes a weakened region 210 which can be broken by manually squeezing pack 202 to cause the liquid from pack 202 to flow into pouch 204.

When it is desired to disinfect a contact lens, a single package 200 is separated from the assembly of packages. The pouch 204 of the detached package 200 is opened along border portion 207 to allow placement of contact lens 224 therein. Pouch 204 is then closed along border portion 207. Pack 202 is then manually squeezed causing the liquid from the pack to pass into pouch 204. The two sidewalls 220 and 221 of pouch 204 are manually squeezed toward each other to rub the matrix pads 222 and 223 against the surface of contact lens 224 for about 30 seconds to insure intimate contact between the hydrogen peroxide, the contact lens, and the matrix pads. The hydrophilic matrix pads 222 and 223 combine with the aqueous medium and swell. The pouch 204 containing the

contact lens is maintained for 2 hours. After this time, the pouch 204 is again manipulated to rub pads 222 and 223 against the surface of lens 224. Pouch 204 is then opened along border portion 207, and the disinfected contact lens 224 is removed from the pouch and placed directly in the wearer's eye for comfortable and safe wear. It is found that the lens 224 is disinfected and that all the hydrogen peroxide originally present is destroyed.

EXAMPLE 5 Non-oxidative Disinfectant Embodiment.

A pouch similar in structure to pouch 204 is provided. As with pouch 204, this similar pouch (which is not attached to a separate liquid filled pack - such is pack 202) is detachably affixed to an assembly of such pouches. This similar pouch includes similar hydrophilic matrix pads to that described with regard to pouch 204 except that the pads include no catalase component. The liquid aqueous medium employed in this embodiment is a substantially isotonic, ophthalmically acceptable aqueous solution containing 1.0% by weight of tromethamine and an effective amount of PHMB. This liquid medium is introduced into the matrix pads during manufacture and is maintained in such pads during system storage.

When it is desired to disinfect a contact lens, a single disinfectant containing similar pouch is separated from an assembly of such pouches. This detached pouch is opened (as pouch 204 is opened along border portion 207) and a contact lens is placed between the matrix pads. No separate liquid phase is apparent in this pouch, which is then closed.

The sidewalls of the pouch are manually squeezed toward each other to rub the matrix pads against the surface of the contact lens for about 30 seconds to insure intimate contact between the contact lens, disinfectant and matrix pads. The pouch containing the contact lens is

maintained for two hours. After this time, the pouch is again manipulated to rub the matrix, pads against .the surface of the contact lens. At the end of the two hour period, the contact lens is removed from the pouch (without encountering a separate liquid phase) and is placed directly into the wearer's eye for safe and comfortable wear. It is found that the contact lens is effectively disinfected. The used pouch is conveniently disposed of . It should be noted that when a non-oxidative disinfectant component is employed (such as in Example 5) , the liquid aqueous medium containing the non-oxidative disinfectant component may be combined with the hydrophilic matrix material present in the pouch during manufacture of the system. In this instance, there is no need to have a separate liquid-filled pack, such as pack 202. Thus, the use of a non-oxidative disinfectant component increases the convenience and ease of using the present system and reduces the size of such system, making storage and disposal more convenient. These advantages are obtained without detrimentally affecting the disinfecting of the contact lens in accordance with the present invention.

While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims.