Present methods of removing deposits are unsatis actory, thus in recent years there haε been an alarming rise in the numbers of people developing eye infections, cαrneal ulcers or even going blind as a direct result of wearing contact lenses. The problem is caused because waste matter produced by the eye which the body would normally excrete is deposited on the lens and thus remains in the eye. The stubborn nature of these deposits means that the compositions currently employed in removing them are very toxic and can cause damage to eye tissue if used too frequently or if they are not thoroughly rinsed after cleaning.

The most common type of deposit to be found on the majority of contact lenses are stubborn and tenacious protein deposits. The incidence of protein deposits amongst contact lenε wearers ranges from very low to nearly 100 percent but over 8 out of every 10 lenses are likely to show depositions. Glycαproteinε, mucoproteins, lyεozymeε, globulins, mucinε, lipidε and calciums are Just some of the substances that adhere to contact lenses during wear Several different deposit removing compositions are currently needed to cope with all of these different substances. Another potentially dangerous consequence of these deposits, especially the protein deposit, is that a disinfecting solution containing preservatives such as chlor ex!dine may chemically bind to the protein on the lens. This may result in both an increased contact time between the preservative and the eye tissue and also an increased concentration of the preservative, which will result in red eye reactions or stinging or burning sensations.

The percentage incidence of these reactions reported in literature seems to vary widely from over 50% to 10% but even the lowest report will be seen to represent a significant proportion of lens wear problems. As result the contact lens industry haε seen a significant shift away from the use

of preservative based disinfecting solutions- The problems caused by protein and other harmful deposits on contact lenses still, however, remains to be solved. It would be desirable to find a contact lenε care system that could remove the vast majority of deposits, especially protein deposits that adhere to objects such as contact lenses, preferably on a daily basis.

Contact lens wearers are at preεent instructed to clean their lenses using a surfactant cleaning solution- However n once protein deposits have formed on the lenε they cannot be removed by surfactant cleaners alone no matter how thin the film of protein may be. Therefore patients are additionally advised to remove protein deposits from lenses by then soaking the lenses in either a proteolytic enzyme solution or PC an intensive cleaning solution for a time of between 15 minutes to 12 hours intermitant y or each weekend. Illustrative compounds are described in US patents Bo.3 910 296 and 4 048 122 respectively. Cleaning lenses intermitantly with such compounds will not protect nor n prevent lenses from collecting all the harmful deposits again in a week of normal daily wear- Cleaning lenses in this way iε also a time consuming procedure which can sometimes last for many hours and thus is often ignored by the lens wearer altogether- Apart from this e. patient is also expected to 5 remove calcium deposits from his lenseε with the aid of a calcium deposit remover which once again requires 15 to 20 minutes to be effective. It would be desirable therefore to find a regimen that could reduce the amount of time it takes to remove stubborn and tenacious deposits from objects such 0 as contact lenses and also be able to remove all harmful deposits in one step.

The present invention provides a safe, convenient and simple method of removing all of these deposits in a matter of seconds. Herewith iε an embodiment in which there iε 5 provided a one step method of cleaning and removing harmful

deposits from objects such aε contact lenses. The process comprises:

1. Immersing the lens in a predetermined volume of an aqueous solution consisting essentially of a protease or other deposit removing compound at a concentration suitable for removing deposits from the lenε.

2. Arresting the action of the deposit removing compound in εaid solution by adding to said εolutiαn an inhibitor or detoxifyer comprising one or more inhibiting/detoxifying compounds (such aε εoya bean sapσnin) in tablet, solution or particle form which react with the protease or other deposit remover in εaid εαlution, and thereby form an aqueous solution containing said reaction products with the addition of mild disinfectants, buffers and stabilizers (i these are desired) and having a pH of 6.5 - 8.5, and a coating encasing said tablet DΓ particles which dissolves gradually in εaid solution so as to release one or more inhibiting/detoxi ying compounds and other water soluble agents only after a predetermined period of time has elapsed, preferably about 15 - 20 minutes, hereby εaid released compounds transform said solution in situ into a buffered lens storage solution. After this the lens should be rinsed briefly before being reinserted into the eye.

The lens should emerge from the solution of said cleaning regimen In a clean, disinfected and deposit free state. In the broadest aspect of thiε invention the inhibitor/detoxifyer is placed into the solution, in which the lens is Immersed, at any time before the lens is freed of deposits, but only after the lenε has been in the solution long enough to be freed of deposits and deproteinized. In the preferred embodiment, the lens and inhibitor are placed into the solution at about the same time, and preferably simultaneously with the inhibitor enclosed within a time capsule whose release iε predetermined. Specifically the detoxifyer/inhibitor iε provided to transform the solution into a buffered and disinfected solution in which the lenε

can be safely stored and this transformation takes place after a predetermined period of time.

The present invention in its preferred embodiment iε particularly advantageous because it lets the wearer perform all the neceεsary steps at one time. In addition, once the lenε, inhibitor and deposit remover are sealed into a container the user doeε not need thereafter to break the sterility. The detoxifying agent will stop the activity of the protease or other deposit remover for the user inside a sterilized environment.

As beforementioned the inhibitor/detoxifying agents can contain water soluble buffering agents and diεinfectantε to provide that when the inhibitor diεεolveε and the activity of the depoεit remover haε been arreεted, the reεultant solution of buffering agents, reaction products and disinfectants iε a stable, buffered solution in which the lenε can be εafely stored.

Alternatively the lens may initially be placed, in a disinfecting solution such aε H202 CHydrσgen peroxide) . In this case the tablet, particle or other solution inhibitor/detoxifyer should also contain compounds that will effectively neutralize the disinfecting solution Ce.g. catalase or sodium pyruvate) as well as compounds that remove the harmful deposits (protease) and also other compounds designed to Inactivate the deposit remover Cεoya bean sapαnin) after it haε had a chance to effectively.remove the deposits from a lenε. Such an embodiment is not as difficult as it sounds to compose so long as all ingredients are held within separate time capsules that are designed to release at predetermined times.

The inhibitor/detoxifyer may <if desired) contain a small amount of a chelating agent εuch as EDTA. In certain circumstances this additive may help retain the stability of other agents in the solution and could also help any preservative or diεinfectant that may be present to retain its activity. The detoxifyer may also include an acid and a

baεe which form an effervescent couple that react in solution to generate a stream of C02 bubbles when the components disεolve.

The detoxifyer/inhi itor may be a coated tablet wherein the components within εaid tablet diεεolve within a predetermined time εpan when placed within the εubject solution. Alternatively instead of having one tablet, a number of particles can be prepared, each particle once again having the ability to release Its contents into the subject solution after a predetermined timespan.

An alternative embodiment of this invention, can be carried out with the aid of a suitable cleaning apparatuε comprising tank meanε that will vibrate or agitate lenses in the tank which contains the appropriate cleaning solution. The cleaning compositions to be used with this embodiment of the invention preferably should comprise at leaεt one catalyst of an acid or alkaline nature. The catalyst will aid the removal of harmful deposits from the surface of the object to be cleaned. The object may then be neutralized by alkali's such as sodium bicarbonate or can simply be rinsed away with saline If the catalyst iε alkaline. The composition may alternatively comprise a group of powerful detergents or surfactants that are known or proven to be effective at removing strongly adhering deposits from objects such as contact lenses. A wide variety of different combinations of detergents or surfactants may be formulated to fulfil this role but it may be necessary to perform a great number of saline rinεeε before the εolution iε thereafter effectively removed from the object. The preferred embodiment will comprise a combination of strong surfactants having dimethyl - polysiloxane - polyoxyalkylene together with the appropriate catalyst as the active ingredient.

When using this composition for cleaning contact lenses, a tablet may be formulated comprising a alkaline substance such as sodium bicarbonate and a disinfecting composition such aε

H202 CHydrogen peroxide), chlorhexidine or chlorine- The tablet is dissolved in a measured amount of H20 or saline and then used to neutralize, disinfect and detoxify the lens after cleaning. It may be preferable to include detoxifying _κ compounds In the initial cleaning solution resulting in a composition which will act to prevent the toxic effects of the solution without substantial loss of its suitability for removing proteinaceous and other depαsitε from contact lenses. The most preferred embodiment iε one that combines

₁ the deposit removing compounds together with the detoxifying compounds and also includes disinfecting agents which will formulate a completely all in one contact lens solution.

The following examples will serve aε an illustration of the , _κ Invent1o . Example 1 This composition will not require neutralization

Dimethyl polysiloxane polyoxyalkylene 0.075

Potassium Silanolate 0.050 n

Example 2

Part CB) of this composition is a tablet prepared on a hand punch to give a tablet of hardness 2.5kg.

<A) Dimethyl polysiloxane polyoxyalkylene 0.075 _κ Akyl carboxylic acid amine condensate 0.050

CB). Sodium Bicarbonate 0.050

Chlorine 0.009

Example 3

_. _n Dimethyl polysiloxane polyoxyalkylene 0.075

Pαlyhydroxyethlmethacrylate 0.040

Carboxymethy1 Ce11u1oεe 0.200

Polyoxyethylene fatty acid eεterε 0.075

Chlorine 0.009

—f.

When a contact lenε containing protein depoεits iε immersed within said composition of deposit removing compounds and is additionally subjected to the specified ranges of epicyclic movement in a rotational or linear sense, the desired reεultε are actually achieved. Protein film and biofilm layers are quickly and effectively removed and the process will help in the removal of the many other deposits that adhere to an object such as a contact lenε. For example the presence of organic protein depoεits on a lenε may prediεpose that lens ι n to buildups of inorganic matter such as calcium and the like. By therefore employing this system to protein deposits a great many other deposits may also be reduced and possibly even eliminated. The time required to remove these deposits and rinse them thereafter can be reduced to a time of

15 approximately 30 - 60 seconds when operating at a frequency of 30 - 50 Hz, thus allowing such a regimen to be performed daily. When rinsing the lens, neutralization of the acid catalyεt may be achieved by using simple, universal compounds such as sodium bicarbonate although the use of an alkaline

20 catalyst may be preferred.

As has been stated different combinations of surfactants can be used with this embodiment of the invention so long aε they are known or are proven to be effective at removing strongly adhering deposits from objects such, aε contact r><~ lenses. Such a composition may once again only require a conventional rinse using a saline solution. Where only a small amount of the depoεitε are present, that have not become too strongly adherent to the lens, the lens may be cleaned by digital cleaning methodε, i . e. gentle rubbing of the subject solution on the lens surface followed by rinsing. However in most cases it will be desirable to clean the lenε uεing the abovementioned cleaning regimen. After cleaning, the lenseε should be placed in a disinfecting and allowed to soak overnight.

35 It will be obvious that changes and modification may be practiced within the invention without departing from the

scope thereof. In thiε embodiment of the invention the lenε to be cleaned is first removed from the eye and then immersed in a vial containing a compound known to be effective at removing proteinaceous depoεits from contact lenses. Suitable compounds include the proteolytic enzymes that are non toxic to the eye of the user of the lenε. Papain iε an enzyme derived from the native green fruit of the tropical pawpaw or melon tree Ccarica papaya) whose clear watery fluid is collected, dried and- sieved to produce papain. Other suitable enzymes Include trypsin, ficin, εubtilisin A, bromelin and other such enzymes known to be effective at removing depoεitε from contact lenses. Normally the lenε would be soaked in this solution for- a period in excesε of 15 — 30 minutes. It would then be required to rinεe the lens very thoroughly thereafter, otherwise reεidual enzyme solution preεent on the lens when re—inserted into the eye, will start to attack eye tissues. In the present invention the lens and enzyme solution is εubjected to epicyclic movement of 30 — 50 Hz and is then exposed to detoxifying compounds which inactivate the enzyme in a process that can be achieved in 30 — 60 seconds.

The detoxifying compounds may comprise εul ydryl reagentε such as iodocietamide or iodocicetic acids which will react with the free εulfhydryl in the enzyme and lead to inactivation of the papain. Soya bean extracts such as soya bean saponin are also known to be inhibitory. Alternatively carbobenzozy-L-glut mic acids or even Chloromethyl ketones of phenylamine and lyslne may help to detoxify the active ingredient. In certain preparations of papain Aldehyde reagentε such as phenlhyyrazine or hydrαykmine will be effective. One of the aforementioned compounds can be uεed in conjunction with Hydrogen peroxide at a concentration of 3%. This cαmpoεition will rapidly inactivate the enzyme and will also serve as an effective disinfectant with excellent antimicrobial properties. In general the detoxifying compounds will act to minimise the accumulation of enzyme

that adheres to the lens and H202 <Hydrαgen peroxide) will reduce the activity of the enzyme to at least 15% of its original activity within one minute.

It should be appreciated that the percentages, quantities and components used in this invention can be modified or used in different combinations. Different deposit removers, inhibitors/detαxifyers or disinfectants may be used in any novel method or combination of methods as disclosed herein. Slight variations may be made to the ingredients or percentages of ingredients without departing from the scope thereof. Thus it would be possible to add calcium sequestering agents if these are deemed necessary. The invention may be used with or without a suitable cleaning apparatuε for cleaning objects such as contact lenses also as deemed necesεary, and a surfactant or surface active as;ent such as Fluronic may be added to the tablet or particles if desired.