A disinfection system for disinfection of contact lenses

The invention concerns a disinfection system for disin¬ fection of contact lenses and comprising a sealed dispos- able package containing a suitable amount of disinfection liquid to disinfect a set of contact lenses.

Users of contact lenses are aware that, at best, contact lenses are to be cleaned and disinfected daily to avoid trouble in use.

In practice, disinfection of contact lenses takes place in that a disinfection liquid from a container is poured into a specially designed lens case in which the cleaning process takes place. The lens case consists of a lens holder with a lens basket usually secured to the under¬ side of the lens case lid as well as a container to re¬ ceive disinfection/neutralization liquid on to which the lid may be screwed. When the contact lenses have been placed in the lens baskets, the lens case lid is screwed on the case, whereby the lens baskets with the contact lenses are immersed into the disinfection liquid in the container and are thereby cleaned.

Various types of liquids are used for cleaning contact lenses, depending on the cleaning system used by the user. One of the systems comprises the use of two liquids, the method comprising first immersing the lenses into hydrogen peroxide (H ₂ O ₂ ), which is a very strong disinfecting cleaning liquid. After the disinfection, the lenses are immersed into a neutralization liquid, and then the contact lenses are ready for use. Sometimes the users of this system forget how far they have come in the cleaning process, and since the neutralization liquid has the same colour as the hydrogen peroxide solution, the user may easily be mistaken or his memory may be at

fault, and consequently there have been several cases where the user has believed that the lenses had been neu¬ tralized and have then inserted them in the eye directly from the hydrogen peroxide solution, which is very pain- ful.

To avoid such unfortunate actions, DK Patent No. 168 746 Bl proposes a cleaning system where the contact lenses are immersed into a two-compartment case with hydrogen peroxide, but where the case contains a third compartment which communicates with the said compartments and in which a soluble tablet containing a neutralization agent (catalase) is placed. The gradual dissolution of the tab¬ let neutralizes the hydrogen peroxide solution so that the contact lenses will be disinfected and neutralized when the tablet has been dissolved completely after a certain period of time. However, a drawback of this dis¬ infection system is that sometimes the user forgets to place the tablet in the case, so that the contact lenses are inserted without having been neutralized. Another risk is that the user inserts the contact lenses before the tablet has been dissolved completely and the hydrogen peroxide solution has not been neutralized completely.

Today, all-in-one liquids have been developed for simul¬ taneous cleaning, disinfection and insertion of contact lenses, the idea being to take the lens directly from the disinfection liquid and to insert it in the eye. The dis¬ infection agent in these liquids is relatively weak, since, otherwise, it would disturb the environment of the eye and cause allergic reactions, because the lenses are not neutralized before being inserted. The all-in-one liquids are supplied in containers/bottles containing up to 360 ml, sufficient for two months' consumption, if the lenses are disinfected daily. In practice, 360 ml are frequently enough for more than two months, as the user

saves or just uses the contact lenses at intervals. Health authorities have generally recommended smaller container sizes, corresponding to one month's consump¬ tion, it being desired to reduce the risk of bacterial growth in the container. Frequently, the container is stored at bathrooms with many bacteria and fungi, and the users frequently forget to screw the lid on to the con¬ tainer after use. An American study (Donzis) has shown bacterial growth in 11-66% of the containers.

The bacterial growth in the containers reduce the effect of disinfection agent, weak as it is, so that its disin¬ fecting effect is reduced (has been reduced) already be¬ fore it gets into contact with the contact lenses. The disinfection of the contact lenses will thus be incom¬ plete, whereby the eye will be liable to infection.

The conclusion has been that the safest form of package of all-in-one liquids is a disposable bottle, commonly called a unit dose, having a ml content corresponding to precisely one disinfection. Such containers containing 15 ml are known, but are relatively expensive, and their bottle-like shape enables the user to use one half and to save the rest for the next day, which involves a risk of bacterial growth.

The previously mentioned lens case is used for disinfect¬ ing contact lenses with the all-in-one liquids and is thus a decisive element of the actual disinfection pro- cess. Because of the ability of bacteria to form their own protecting biofilm, it is difficult to keep the lens case clean, and today it is therefore recommended to ex¬ change the case as frequently as every month. Exchange every three months is perhaps acceptable, if the user users a strong disinfection agent, e.g. 3% hydrogen per¬ oxide, which, however, requires neutralization of the

disinfection agent and the lens before the lens is in¬ serted.

Studies (Donzis) have shown that bacterial growth in lens cases differs significantly, depending on the disinfec¬ tion agent used, within 3 weeks' use of a new case. If the hydrogen peroxide system is used, there is no bacte¬ rial growth within the first 3 weeks. If, however, all- in-one systems are used, growth occurs in 25% of the cases within the first 21 days. Thus, with bacterial growth in the case, the situation is quite different when using a so-called all-in-one system as the disinfection system.

The conclusion of the study is that if an all-in-one dis¬ infection system is used, it is very important to main¬ tain the effect of the disinfection agent during storage in the container at the user's. Further, it is very im¬ portant to use a sufficient and correct amount of disin- fection agent to disinfect the contact lenses. In addi¬ tion, the lens case is to be exchanged, or sterilized in another manner to avoid reducing the effect of the disin¬ fection agent in relation to the lens with the consequent risk of eye infection.

EP Al 381 616, EP Al 401 163 and FR Al 2 674 217 disclose disposable systems for cleaning contact lenses.

EP Al 381 616 concerns a disposable system for cleaning contact lenses, which comprises a first container to re¬ ceive contact lenses and a second container containing sterilization or disinfection agent. The first container has a means to pierce the lid on the second container when the second container is folded over the first con- tainer. The container with contact lenses contains a catalyst to degrade the sterilization agent.

EP Al 401 163 concerns a disposable system comprising two pairs of containers. The first pair contains a steriliza¬ tion agent, and the second pair contains a neutralization agent. Contact lenses are cleaned by first placing the lenses in their respective containers with sterilization agent and then transferring the lenses to the containers with neutralization agent. The system may be provided with a lid, if the lenses are to be stored in the system for an extended period of time. Further, the system may be provided with a spoon-like means to handle the lenses.

FR Al 2 674 217 concerns a disposable container contain¬ ing a cleaning liquid. In use, the lid of the container is removed by breaking a fragile area, and then the lenses are placed in the liquid. The lid may be applied to the container again.

These disposable systems have a number of drawbacks:

The lenses are be to handled either by the fingers or by a spoon-like means, which makes handling risky and lens damage likely.

- The disposable systems are restricted either to all- in-one liquids or to two-liquid disinfection systems.

The disposable systems are made of a fragile material, which makes them mechanically unstable during transport (risk of leakage) .

It is likely that the lenses are discarded together with the disposable system, as the lenses are difficult to see when they are present in the liquid.

The object of the invention is to provide a method of disinfecting contact lenses in a lens case filled with a disinfection liquid, where the contact lenses are placed in a lens basket suspended from a case lid and down in the disinfection liquid when the lid is screwed on to the container, obviating the above-mentioned drawbacks, and to ensure that the lens user uses the correct amount of disinfection liquid, and to ensure that the effect of the disinfection liquid is maintained until the moment when it contacts the contact lenses.

This object is achieved by a new distribution principle which radically departs from the traditional principles, where distribution of disinfection liquids to disinfect contact lenses takes place in larger or smaller bottles from which the user pours the disinfection liquid into the container of a lens case in which the disinfection process takes place.

The new distribution principle consist of a new disinfec¬ tion system to disinfect contact lenses of the stated type, characterized in that the disposable package is formed by a disposable container formed with such a wide mouth as to be suitable for receiving holding means for contact lenses, whereby the disposable container may be used as a disinfection container in connection with dis¬ infection of the contact lenses. Thus, in addition to serving as a distribution unit in the form of a dispos¬ able package, the disposable container also serves as a disinfection container/vessel in connection with disin¬ fection of contact lenses. With the new principle, both the disinfection liquid and the disposable container are exchanged after completed disinfection of the contact lenses, thereby eliminating the risk of bacterial growth in the container in which the disinfection takes place, and allowing the disinfection liquid to maintain its op-

ti um effect until the moment when the seal on the dis¬ posable container is torn off and the lens baskets with the contact lenses are immersed into the disinfection liquid. Another advantage of the new disinfection prin- ciple is that when using disposable containers it ensures that the lens user uses the correct amount of disinfec¬ tion liquid to disinfect the contact lenses.

At its opening, the disposable container is provided with an annular flange on whose upper side a tear-off sheet seal is attached, as stated in claim 2. This attachment method, providing a good contact face between the sheet and the flange, ensures that the disinfection liquid is protected effectively against bacterial attacks during storage until use. The flange moreover has several other functions, which will be mentioned below.

When the disposable container can also accommodate the means stated in claim 3 to receive the contact lenses or holding means for these, it is additionally ensured that the contact lenses may be effectively disinfected, and following disinfection of the contact lenses, it is moreover possible - in addition to exchange of disinfec¬ tion liquid and the container in which the disinfection process takes place - to exchange the lens baskets more frequently than in the use of the traditional lens cases. The frequent exchange of the lens baskets means that they will not be infected by bacteria before they are ex¬ changed. When the lens baskets are stored in the dispos- able containers containing disinfection liquid, the lens baskets may be considered to be sterile until the moment when the seal is torn off.

When the means to receive the contact lenses are formed by disposable lens baskets, as stated in claim 4, the use of the disinfection system of the invention ensures that

the contact lenses may always be disinfected in an envi¬ ronment which is not infected by bacteria beforehand.

When the means to receive the contact lenses are arranged on a stem whose free end protrudes from the disinfection liquid level, as stated in claim 4, it is ensured that contact between the user's fingers and the disinfection liquid in the disposable container is reduced to a mini¬ mum.

When the disposable container is additionally provided with a removable lid fitting tightly along the rim thereof, as stated in claim 5, it is moreover ensured that the disinfection takes place in a closed environ- ent, and that it is possible to store the contact lenses in the disposable container for an extended period of time, like with the use of the known lens cases. The dif¬ ference, however, is that the user can decide that also the lid is just to be used once like the disposable con- tainer and the disposable lens baskets. This provides a complete disposable disinfection system which eliminates all the drawbacks of the known all-in-one systems at the same time. The user may freely decide to exchange the lens baskets and the tight-fitting lid after each disin- fection or not, as both lens baskets and lids may be used again. The system is conceivably designed such that dis¬ posable containers may be purchased with and without lens baskets, and with and without lids.

Also, as stated in claim 6, the disposable container may be constructed such that it may be placed as a disposable insert in a container of a lens case, following which the seal across the opening is torn off prior to the mounting of the lid with the lenses in the lens baskets. The addi- tional advantages of this are that the lens case con¬ tainer, which usually consists of a cylindrical transpar-

ent container of impact-proof plastics, and which takes more resources to manufacture than the disposable con¬ tainer, does not have to be exchanged with the common frequency, as it does not contact the disinfection liquid and is thus not subjected to bacterial attacks. Further, the lens case container is used for protecting the dis¬ posable container.

The disposable container of the invention containing means to receive the contact lenses or holding means (disposable lens basket) for these finds application as an insert in primitive lens cases which do not comprise a lens basket, as stated in claim 7.

Also special lens cases may be constructed, whose shape is adapted for use together with disposable containers of the invention, as stated in claim 8, the container of the lens case being used for receiving a disposable container containing disinfection liquid into which the lens bas- kets with the contact lenses are immersed when the lid is screwed on to the lens case.

The protruding flange on the disposable container, stated in claim 9, provides a tight connection between the lid of the lens case and the disposable container, so that the container of the lens case is not contaminated by bacteria from the contact lenses, as the interior thereof does not get in contact with the disinfection liquid of the disposable container. The container of the lens case is thus used for securing and protecting the disposable container in the correct position below the lens baskets, as well as an additional protection against bacterial at¬ tacks.

The disinfection system of the invention is moreover ex¬ tremely useful in connection with the use of the system,

comprising a first cleaning in hydrogen peroxide (H ₂ O ₂ ) and a subsequent neutralization in a neutralization liquid, as the user is always certain of how far he gas got in the disinfection process, since the disposable containers are discarded as they are used. Thus, if the contact lenses are being disinfected in H ₂ O ₂ , the dis¬ posable container containing the neutralization liquid will be juxtaposed with unbroken seal, thereby enabling it to be observed that the neutralization process has not been completed. A further safeguard against wrong use of disinfection liquid and neutralization liquid may com¬ prise providing the disposable containers for the respec¬ tive liquids with mutually different colours and/or shapes, as stated in claim 10. This minimizes the risk of inserting non-neutralized contact lenses when using the disposable containers according to the invention.

The containers containing H ₂ O ₂ and neutralization liquid, respectively, may have different shapes and appearances, and the upper sides of the seals thereof may be provided with marks clearly indicating what the containers con¬ tain, thereby reducing the risk of mistakes.

Of course, the disposable containers are relatively small, as they are intended to be accommodated in the container part of the lens case. This means that these occupy very little space, and as a result the new distri¬ bution system, in addition to the advantages already men¬ tioned, also has the same advantages with respect to space requirement as the known all-in-one disinfection liquids which are supplied in unit dose packages.

The invention will be explained more fully below with reference to the drawing, in which

fig. 1 is a perspective view of an unopened disposable container with a lid,

fig. 1A is lateral sectional view of fig. 1, containing disposable lens baskets,

fig. 2 is a perspective view of fig. 1A, with partly re¬ moved seal,

fig. 3 is an exploded lateral view of fig. 2 during in¬ sertion of contact lenses into the disposable lens bas¬ kets,

fig. 3A shows the disposable container used as an insert in a primitive lens case,

fig. 4 is a lateral sectional view of the disposable con¬ tainer in an assembled state,

fig. 5 shows the disposable container during removal of the tear-off sheet,

fig. 6 is a lateral sectional view of the disposable con¬ tainer used as an insert in a normal lens case.

fig. 7 is a perspective view of a lens case to receive disposable containers, and fig. 8 is a lateral sectional view of a lens case with inserted disposable container during cleaning of contact lenses.

The disinfection system 1 of the invention is shown in fig. 1 in an unopened state and comprises a disposable container 18 with a tear-off sheet seal 22 secured on an annular flange 26 (fig- 2). The disposable container 18 is formed with such a wide mouth as to be suitable to re-

ceive holding means 14, 19 for contact lenses 16 during the disinfection process.

As shown in fig. 1A, a removable, tight-fitting lid 28 may be provided along the rim of the disposable container above the sheet seal 22. Further, the disposable con¬ tainer 18, in addition to the disinfection liquid 24, may also contain a set of lens baskets 19 secured to a stem 21, whose free end protrudes above the disinfection liquid level.

When the disinfection system 1 is to be used, the lid 28 is removed from the disposable container 18, and then the sheet seal 22 is torn off (fig. 2). Then, the stem 21 is grasped by the finger tips and the lens baskets 19 are lifted out of the disposable container 18. The contact lenses 16 are then placed in the lens baskets 19, as ap¬ pears from fig. 3, and these are immersed into the dis¬ posable container 18 by again grasping the free end of the stem 21 by the finger tips. The lid 28 is applied over the opening of the disposable container (fig. 4), and the disinfection process takes place.

The disposable container 18 may also be used as an insert in a simple lens case 3, without lens basket, as appears from fig. 3A. This embodiment of the disinfection system does not comprise the lid 28, the protruding flange 26 on the disposable container 18 being clamped between the rim of the lens case 5 and a sealing member 13, cooperating with it, in the form of an 0-ring seal on the lid 7 of the lens case. Placing of the contact lenses 16 in the lens baskets 19 in connection with the disinfection pro¬ cess takes place as described before.

The embodiment of the disinfection system 1 shown in fig. 5 for use together with traditional lens cases, with lens

baskets 14 secured to a stem 15 whose free end is secured in the lens case lid 8, comprises a disposable container 18 with the tear-off sheet seal 22 described before. In use, as disclosed in fig. 6, the disposable container 18 is placed in the container 4 of the lens case, before or after the sheet seal 22 is torn off. The contact lenses 16 are then placed in the lens baskets 14, and the lid 8 is applied to the container 4, whereby the lens baskets 14 containing the contact lenses 16 are immersed into the disinfection liquid 24. Application of the lid 8 causes the protruding annular flange 26 to be clamped between the rim of the container 4 and a sealing member 13, coop¬ erating with it, in this case an O-ring on the lid 8.

A lens case 2 for use together with the disinfection sys¬ tem 1 of the invention is shown in a disassembled state in fig. 7. The lens case 2 consists of two main parts, a container 4 whose external rim has bayonet threads 6 to enable the lid 8 to be screwed on.

As appears from fig. 7, the inner side of the lid 8 has a plurality of gripping flaps 10 intended to engage the bayonet threads 10 on the container 4. An inner side 11 of the bottom of the lid is formed with an annular groove 12 in which a seal 13, in this case an O-ring, of a suit¬ able material is embedded. The O-ring 13 is so posi¬ tioned in the lid 8 that when the lid is screwed on to the container 4, the O-ring engages the upper edge of the container. As appears from fig. 8, the underside of the lid 8 has two lens baskets 14 carried by a stem 15 which is inserted into the central hole 9 of the lid, said bas¬ kets being intended to receive a set of contact lenses 16. When the lid 8 is screwed firmly on to the container 4, the lens baskets 14 extend down into the interior of the container.

Fig. 7 additionally shows two containers 18, 20 in the shape of a cup having an annular flange 26 along the rim. One container 18 has an intact seal in the form of a tear-off sheet 22. The tear-off sheet 22 is removed on the other container 20, which contains disinfection liquid 24. The cups 18, 20 are shaped such that they may be received in the container 4, so that the annular flange 26 engages the upper edge of the container. In the applied position of the case lid 4, the O-ring engages the annular flange 26 on the disposable container 20 (fig. 8), thereby forming a tight connection between the container 20 and the lid 8. In the same position, the lens baskets 14 extend down into the liquid in the con¬ tainer 20.

Disinfection of contact lenses 16 takes place by placing these in the lens baskets 14, following which the dispos¬ able container 20 is placed in the container 4, and the sheet 22 across the mouth on the disposable container 20 is torn off. The lid 8 is then threaded on to the con¬ tainer, thereby causing the lens baskets 14 containing the contact lenses 16 to be immersed into the disinfec¬ tion liquid 24 which is present in the container 20, and which has maintained its optimum effect till now. After completed treatment, the lid 8 is screwed off the con¬ tainer 4, and the disposable container 20 with the spent liquid is discarded. If a two-liquid disinfection system is used, the container with the neutralization liquid is then inserted into the container 4 after tearing-off of the disposable sheet 22, and the lid 8 is screwed on again, following which the neutralization process takes place.

If the user of the contact lenses is particularly careful with the cleaning of his lenses, the lenses are rubbed before being disinfected. The mechanical action results

in a better cleaning of the bacterial film and of other impurities on the lenses than the disinfection which takes place merely by immersing the lenses into disinfec¬ tion liquid. A little liquid is necessary for the rub- bing, which is performed by a finger. The spent liquid from the preceding disinfection may be used for this pur¬ pose, or sterile brine. As the lid and container of the lens case are sealed, it is thus possible to store the liquid after the disinfection until rubbing is to be per- formed. After rubbing, the disposable container with the spent liquid is discarded, a new one is inserted, and the actual disinfection of the contact lenses takes place.

It is common to the use of the disinfection system 1 of the invention that both the disposable container 18 and the spent disinfection liquid 24 present in the container are discarded after the completion of the disinfection of the contact lenses 16.

If the disinfection system 1 also comprises holding means in the form of lens baskets 19 as well as a cover 28, these parts are discarded together with the container 18 and the spent disinfection liquid 24. If the user does not want to exchange the cover 28 and the lens baskets 19 after each disinfection of contact lenses, these parts may be used again together with the embodiment of the disinfection system which does not comprise these parts. Hereby, precisely the exchange frequency of lens baskets 19 and cover 28 desired by the user, may be achieved.

As an additional safeguard against contamination in con¬ nection with the disinfection process, the cover 28 may also be provided with a tear-off film on the side facing the container mouth, said film being removed immediately before the application of the cover on the container.

Thus, the described disinfection system provides a method of ensuring that the correct amount of disinfection liquid is used for the disinfection of contact lenses, thereby eliminating the danger of bacterial growth in the case container.

The use of the method and the lens case of the invention in connection two two-liquid disinfection systems reduces the risk of inserting non-neutralized contact lenses practically to zero, as the user can always observe how far he is in the cleaning process on the basis of the shape and colour of the containers.

If the disposable containers, containing H ₂ O ₂ and neu- tralization liquid, respectively, are made of a material of different appearance and/or shape, e.g. with different colours, the risk of inserting non-neutralized contact lenses is reduced additionally, as the user, by looking at the disposable container, can see what it contains ( e . g . red container contains H ₂ O ₂ , and green container contains neutralization liquid) . The different container colours are relevant particularly where the user has torn off the seal on both containers at the same time, it be¬ ing of paramount importance to the user to know which container contains which.

What remains is thus how to keep the lid 8 and the lens baskets 14 free of bacteria in the lens case 2 for use together with the disinfection system 1. However, ex- change of the baskets will hardly be necessary, as the disinfection takes place in liquid with unreduced strength. As an additional safeguard, the lid 8, the 0- ring 13 and the lens baskets 14 may be made of a material resisatnt to boiling, thereby allowing these to be boiled, optionally in a weak brine solution, which kills

the bacterial cultures that might have survived the dis¬ infection with the disinfection liquid.

The disposable containers may be made with a quite small thickness in an inexpensive manner, e.g. as vacuum formed sheet elements, as these will be protected by the con¬ tainer of the lens case in use. Further, they are usually supplied in multi-unit boxes with a suitable strong pack¬ age optionally formed as a dispenser, or suitable in such a one, suspended from a wall or the like.

It is contemplated that the containers 18 of the disin¬ fection system and the lens baskets 19, 14 as well as the special lens case 2 are made of recyclable plastics mate- rials to the greatest possible extent.