GB2191019A - Contact lens case - Google Patents

Abstract

A device, adapted to allow a contact lens or another object to be brought into and out of contact with a liquid, comprises first and second mutually-displaceable members 10 and 12 in liquid-tight sealing 16 relationship; in which the first member has a recess 14 (in which the object can be placed), which can be brought into or out of contact with the second member; and in which the second member has a plurality of chambers 20A, 20C which can each be brought into contact with the recess 14, independently and sequentially. The first member 10 may be coaxial with the second member 12 which may be annular. <IMAGE>

Description

SPECIFICATION Contact lens case This invention relates to devices such as contact lens cases which are adapted to allow an object such as a contact lens to be brought into and out of contact with a liquid.

Many types of contact lens need to be stored in an aqueous environment, while not in use in the eye. This is particularly true of soft hydrophilic (SH) contact lenses, but it also applies to lenses made of the most recent forms of rigid gas-permeable (RGP) materials.

SH and RGP lenses together probabaly represent 80% of all contact lenses now in use in the United Kingdom at least.

Contact lenses should be clean and sterile when inserted into the eye. When lenses are removed in the evening and stored overnight, it is normal for them to be subjected to a sterilisation process, prior to reinsertion in the morning. Various processes are known.

One known sterilisation process comprises thermal sterilisation (or asepticisation), in which the lenses are placed in a case (or in a holding frame within the case). The case is filled with saline and heated, after which the lenses are allowed to cool, while still sealed in the case, until ready for use. The interior of the case, the solution and the lenses are thus all rendered sterile, and remain sterile until the lenses are removed. No special or separate provision for steriiising the interior of the case is necessary.

Another known process comprises chemical sterilisation, using one solution. In this process, the lens is placed in a case (or in a holding frame within the case) and immersed in a chemical solution sufficiently active to kill all the biologically-active agents likely to be present, such as bacteria, fungi and spores.

Such solutions automatically sterilise the lens and the entire interior of the case. However, for SH or RGP lenses which may absorb or bind some of the solution, the solution must also be eye-compatible; such solutions are therefore unlikely to be sufficiently biologicallyactive to achieve complete sterilisation.

Two or more separate solutions are thus commonly used. For example, there are (1) a strong sterilising solution and (2) a neutralising or washing solution. In some systems, the neutralising solution is an acceptable long-term storage or soak solution; in other systems, a third, storage solution is used. Multi-component systems are typified by the combinations of (1) hydrogen peroxide and (2) neutralising solution which are widely commercially-available, and used with both SH and RGP lenses.

Multi-component systems are currently used by placing each lens in solution (1) in a case for a given minimum time, removing the lenses, emptying the case of solution (1), filling it with solution (2) and reinserting the lens for a second predetermined time, to achieve nutralisation. It is clear that, if solution (2) is to be eye-compatible, it will not be sufficiently strong to protect against contamination picked up during the emptying/refilling process, when the lens holder is physically removed from the case.

A device according to the present invention, adapted to allow a contact lens or another object to be brought into and out of contact with a liquid, comprises first and second mutually-displaceable members in liquid-tight sealing relationship; in which the first member has a recess (in which the object can be placed) which can be brought into and out of contact with the second member; and in which the second member has a plurality of chambers which can each be brought into contact with the recess, independently.

By way of example, the first member is essentially cylindrical and the second member essentially annular. In this case, the first member can be movable axially and by rotation with respect to the second member. Preferably, there are an even number of chambers and, for reasons which will become apparent below, the number is twice that of the number of liquids used in sterilisation.

When a multi-component system is used, and only one of the solutions is capable of achieving sterilisation, it is important that the chambers are used in rotation, so that each chamber is left sterile prior to the use of the (non-sterilising) neutralising solution. The present invention allows what is thus very desirable, i.e. the sequential use of chambers during repeated operation of the device, so that all the chambers are automatically sterilised internally during repeated use.

The invention will now be described by way of example only with with reference to the accompanying drawings. In the drawings: Figure 1 is a cross-sectional side view of an embodiment of the invention; and Figure 2 and 3 are cross-sectional plan views of the embodiment of Fig. 1, respectively along the section lines A-A' and B-B' (from opposite directions, for simplicity); Fig.

3 shows also an associated lens mount.

Fig. 1 shows a generally cylindrical first member 10 and a generally annular second member 12 which is coaxial (along the line X-Y) with the first member 10. The first member 10 has an axial length (L,) at least twice that (L2) of the second member 12. The first member 10 is a snug fit within the second member 12, and can be moved axially, or rotated, with respect to the second member 12 while maintaining a liquid-tight (but not necessarily fluid-tight, to avoid pressure buildup on generation of a gas in situ) sealing relationship therewith by virtue of seals 16.

The first member 10 includes two recesses 14 which, in the arrangement shown in Fig. 1, are open to the atmosphere. In this arrangement, a contact lens can be inserted into each of the recesses 14. Fig. 1 also shows a cover plate 28 having apertures 30A and 30B.

As shown in Fig. 2, the second member 12 includes four segments 18A, 18B, 18C and 18D, each having an inner boundary of length x, defining four chambers 20A, 20B, 20C and 20D. The chambers are open to the inside of the annulus, and each has a sealable inlet/outlet, two of which are the inlets 22A and 22C (in chambers 20A and 20C, respectively) shown in Fig. 1.

Fig. 3 shows the configuration of a recess 14, the opening to which has an arc length z, and into which can be inserted a contact lens or contact lens holder 24. Fig. 3 also shows a cut-out 26 adapted to cooperate with detents (not shown) on the cover plate 28.

In use of the device, a contact lens is inserted into each of the recesses 14. For this purpose, a lens may be mounted on a mount 24 adapted to be inserted into the recess.

Such a mount is advantageously constructed of soft plastics material, or may be equipped with soft hydrophilic plastic inserts, to prevent damage to the lens. This step is conducted while the device is in the configuration shown in Fig. 1 and, in the same configuration, chambers 20A and 20C are respectively filled with solution (1) and solution (2) through the respective apertures 22A and 22C.

The member 10 is then pushed "down" (in the direction of Y) axially with respect to the member 12, so that the recesses come into contact with the chamber 20A. Solution (1) floods the recesses 14 and sterilisation of the lens begins.-After a suitable period of sterilisation, the member 10 is rotated through 90 , bringing the recesses into communication with the previously empty chamber 20B. The solution (1) in the recesses empties into the chamber 20B; the recesses are thus drained and the interior of the chamber 20B is thus sterilised.

The member 10 is rotated through a further 900. The recesses are now in communication with solution (2) in the chamber 20C, thus allowing neutralisation. After neutralisation, the member 10 is rotated through a further 90 , whereupon the neutralising solution (2) empties into the chamber 20D. The member 10 is then moved axially in the direction of X, to expose the recesses 14 and allow removal of the lenses, for use.

For successful operation of the illustrated embodiment, x < z < 2x.

The given steps have been described independently of the (optional, but preferred) cover plate 28 illustrated in Fig. 1. The cover plate 28 is mounted over the apertures 22A etc. of the member 12, and is geared so that, for each rotation of the first member 10 through 360 , the cover plate 28 rotates through 90 or 1800 (180 is preferred). This cover plate indexes the chambers, and ensures that they are used in strict sequence, first for sterilisation solution (1) and then for neutralising solution (2).

The cover plate 28 should be clearly marked with instructions to use the proper solutions through its two apertures 30A and 30B; the correspondence of these apertures with, say, apertures 20A and 20C (as shown in Fig. 1) is preferably biased by providing location means comprising the cut-out 26 (see Fig. 3), or a key-way or other suitable shape, thus ensuring that the lenses always start the cycle of use in contact with solution (1), whichever of the chambers happens to be in use for solution (1) on that occasion. During the procedure described above, the indexed cover plate rotates through 1800, so that the next cycle of use begins with chamber 20C for sterilising solution (1) and chamber 20A for the neutralising solution (2). Thus, the nonactive solution (2) occupies chambers 20A and 20B, both left sterile by the use of solution (1) in the previous cycle.

The indexed cover plate can provide at least four desirable functions, i.e. (i) in combination with location means, it defines the correct starting positions of the members 10 and 12 relative to each other, (ii) it allows only the correct chambers to be filled, (iii) it allows rotation in the correct direction, and (iv) it allows the member 10 to be withdrawn, for removal of the lenses, only after the full cycle of treatment is complete.

If desired, a device of the invention may be operated electronically/automatically, e.g. by being mounted on a powered timing base.

Such operation could be controlled in a way which ensures that each step of the given procedure last for the necessary period of time. A user could initiate automatic operation of a device of the invention before going to sleep.

If desired, the member 10 may include a cross-drilling which allows mixing of the solutions in chambers 20A, 20B and 20C as the member 10 is rotated into its final position.

This would ensure that the solutions cannot be kept and re-used by the user.

By using a device according to the present invention, contact lenses are treated using multi-component systems, without exposure to reinfection after the initial sterilisation stage.

If n is the number of chambers, each chamber is sterilised every n/2 complete turns, e.g. every other day if n is 4.

A device of the invention may be operated using conventional materials. Alternatively, compositions of the type described and claimed in British Patent Application No.

8607883 may be used. Further, an alternative to the use of a "free" solution comprises preimpregnating a hydrophilic membrane with sterilising material, either in the form of a solution, e.g. peroxide, or some other form, such that when the contact lens is pressed between two hydrophilic membranes, the sterilising material acts upon the -surface of the lens to sterilise it. In this development, the size and volume of the membranes can be calculated to ensure that the correct dose of sterilising material is delivered accurately to the lens surface. It may be advantageous to incorporate hydrophilic materials into a lens holder used in the device described above, in order to provide mechanical protection to the lens, whether or not that hydrophilic material is used to apply sterilising material to the lens surface.

Ozone is a preferred sterilising medium. A device of the invention could be adapted to initiate the generation of ozone (or another sterilising agent such as hydrogen peroxide) in the appropriate chamber when a lens is brought into contact with that chamber.

Claims (8)

1. A device, adapted to allow a contact lens or an other object to be brought into and out of contact with a liquid, which comprises first and second mutually-displaceable members in iiquid-tight sealing relationship; in which the first member has a recess (in which the object can be placed), which can be brought into or out of contact with the second member; and in which the second member has a plurality of chambers which can each be brought into contact with the recess, independently and sequentially.

2. A device according to claim 1, in which the first member is essentially cylindrical and the second member is essentially annular.

3. A device according to claim 1 or claim 2, in which the second member has an even number of chambers.

4. A device according to claim 3, in which the second member has four chambers.

5. A device according to any preceding claim, in which each chamber has a closable aperture for liquid inlet/outlet.

6. A device according to any preceding claim, which comprises a hydrophilic lens holder.

7. A device according to claim 1, substantially as illustrated in the accompanying drawings.

8. A method of cleaning a contact lens, which comprises introducing the lens into the recess of a device according to any preceding claim, and bringing the lens into successive contact with a sterilising solution in one chamber, and a neutralising or washing solution in another chamber, of the device.