BRUUN JENSEN JOERGEN (DK)
| WO1994001800A1 | 1994-01-20 |
| US5089240A | 1992-02-18 | |||
| EP0209071A1 | 1987-01-21 | |||
| US5196174A | 1993-03-23 |
| 1. | An apparatus for disinfecting contact lenses by immersing said lenses in a reaction vessel with disinfecting liquid in form of a hydrogen peroxide solution H2O2, said contact lenses prior to the immersion being placed in basket or netlike lens holders on a frame with a compartment, where the walls of said compartment are provided with inlet openings for the H2O2 solution, and in which a catalytic element is introduced for gradually de¬ composing the H2O2concentration over a period, c h a r a cte r i s e d in that the walls of the compartment (7) comprise an apertured system of spokes (10; 10a to 10h) abutting the catalytic element (9) and extending outwards from said element, whereby the oxygen, O2, developed during the decomposition of the H2O2concentration is collected below said spokes and maintained in contact with the catalytic element (9) and only slowly escapes from said spokes. |
| 2. | An apparatus as claimed in claim 1, c h a ra cte ri s ed in that the spokes (10a to 10h) are downwardly inclining away from the catalytic element (9) to form downwardly facing air pockets (11), and that one or more small apertures (23; 12) are accommodated in connection with the spokes for the slow escape of the oxygen. |
| 3. | An apparatus as claimed in claim 2, c h a r a ct e r i s e d in that the spokes are interconnected and extend as a helical winding (10) rising along a vertical axis in the use position, said helical winding (10) surround¬ ing the catalytic element (9). |
| 4. | An apparatus as claimed in claim 3, c h a r a c t e r i s ed in that the end of the helical winding (10) being uppermost in the use position is provided with a small aperture (23) through which the oxygen slowly escapes. |
Technical Field
The invention relates to an apparatus of the type described in the preamble of claim 1 .
Background Art
Contact lenses must be disinfected by the user when they are removed from the eyes. The most well-known disinfecting system is based on hydrogen peroxide H 2 O 2 , which in the highly purified form and in acid environment is highly destructive to all microorganisms. The hydrogen peroxide can be neutralized into oxygen and water by means of either a catalyst system or an enzyme system in such a manner that the hydrogen peroxide is removed from the contact lenses before said lenses are to be used again.
The apparatus of the type stated in the preamble of claim 1 comprises as indicated in said preamble a catalyst system for decomposing or neutraliz¬ ing the hydrogen peroxide in the disinfecting liquid.
The commonly used hydrogen peroxide solution contains 3% H 2 O 2 . A wide range of tests has shown that the best effect of the disinfecting system is obtained by using such a concentration of hydrogen peroxide of 3% for at least 20 minutes.
Palatinates are for instance used as catalyst for neutralizing the hydrogen peroxide. The used 3% hydrogen peroxide solution is, however, neutral¬ ized by the known systems down to 1 % already during the first 1 to 2 minutes, which is unsatisfying for obtaining a good disinfecting effect.
Another problem is found in the fact that the neutralization of the hydro¬ gen peroxide according to the catalyst principle goes very slowly in con¬ nection with the very low concentrations with the unfortunate result that small amounts of hydrogen peroxide may remain in the contact lenses, i.e. concentrations being so high that they can irritate the eyes.
US-PS No. 5,089,240 discloses an appliance of the above type for disin¬ fecting contact lenses. The appliance disclosed by this US patent involves the use of a catalytic element consisting of two elements in order to rem¬ edy the above problems.
The first catalytic element is most active in the initially very high concen¬ tration of H 2 O 2 . The material composition of this first element described in greater detail in the description can delay the neutralizing speed slightly with the result that 1 % of H 2 O 2 still remains in the solution after a neutral¬ ization for 30 minutes of a starting concentration of 3% H 2 O 2 .
This first catalytic element ceases to have an effect after 80 to 90 min¬ utes at an H 2 O 2 -concentration of approximately 1 00 ppm. Unlike this first catalytic element, the second catalytic element is primarily effective at lower H 2 O 2 -concentrations, such as 300 ppm, due to its material composi¬ tion, and it continues its neutralizing effect in such a manner that an H 2 O 2 -concentration of less than 1 5 ppm is in fact obtained within 6 hours, which is indicated to be a concentration not irritating the eye.
Brief Description of the Invention
The object of the invention is to provide an apparatus which also assists in maintaining a high H 2 O 2 -concentration for 20 minutes, and which subsequently assists in neutralizing the H 2 O 2 -solution down to such a low value that the remaining amount of H 2 O 2 on contact lenses does not irritate the eyes.
This object is according to the invention solved by the subject matter of the characterising clause of claim 1 .
The oxygen released during the neutralization of H 2 O 2 is collected below the spokes and retained for a short period of time on the surface of the catalyst, whereby it blocks up the access of H 2 O 2 . The neutralization of H 2 O 2 goes slowly in this phase due to the O 2 -blocking of the surface of the catalyst.
When the concentration of H 2 0 2 nevertheless drops after a suitable period of time which suffices for obtaining a good disinfection, the release of 0 2 from the H 2 O 2 -solution is gradually slowed down in such a manner that the O 2 -blocking of the surface of the catalyst finally ceases. Now the catalyst is freely accessible for the H 2 O 2 -solution in such a manner that the neutralization of the remaining H 2 O 2 -concentration is accelerated relative to the previous phase involving the O 2 -blocking of the surface of the catalyst. During this second phase, a large catalyst surface is free for the neutralization of the remaining hydrogen peroxide.
Claim 2 deals with an advantageous embodiment according to the inven¬ tion, as the oxygen is collected in the downwardly facing air pockets between the bottom sides of the spokes and the surface of the catalyst, and as said oxygen only slowly escapes through the small apertures.
Claim 3 deals with an embodiment allowing the developed oxygen to slowly rise along the helical winding.
Several small apertures can be provided for the escape of the oxygen from the helical winding, but only one winding is necessary at the top of the winding as stated in claim 4.
Brief Description of the Drawing
The invention is explained in greater detail below with reference to the accompanying drawing, in which
Fig. 1 is a cross-sectional view through a first embodiment according to the invention,
Fig. 2 is a sectional view taken along the line ll-ll of Fig. 1 ,
Fig. 3 is a cross-sectional view through a second embodiment according to the invention, and
Fig. 4 is a sectional view taken along the line IV-IV of Fig. 3.
Best Mode for Carrying Out the Invention
The corresponding parts have the same reference numerals in the drawing.
The apparatus shown in the Figures of the drawing comprises a cylindrical reaction vessel 1 , onto which a cover 4 can be screwed by means of a threaded connection 2. A gasket 4 is provided between the reaction vessel 1 and the bottom side of the cover 3. As illustrated in Fig. 2, the cover comprises an air-escape opening 5, but instead of this opening 5 the gasket 4 can be shaped in such a manner that it allows a ventilation from the interior of the reaction vessel.
A frame 6 is secured to the bottom side of the cover. In the illustrated embodiment this frame is formed as a two-pronged fork, whereby a cata- lytic element 9 is inserted between the legs 8 of said fork. The catalytic element is retained by way of friction both between the legs 8 of the frame and between the walls 7 of the compartment. The walls 7 comprise apertured spokes 1 Oa. to 10h.
These spokes extend obliquely downwards away from the surface of the catalytic element in such a manner that four spokes are provided on each side of the compartment 7, cf. Fig. 1 . The number of spokes is, however, not decisive and can be determined according to desire. As shown in Fig. 1 , the spokes are curved, but they may also be plane. As previously men¬ tioned, the shown spokes are inclining downwards away from the catalytic element, and in addition the spokes incline relative to horizontal, cf. Fig. 2. It should be stated that the spokes can be arranged perpendicular to the surface of the catalytic element or even be slightly upwardly inclined, such as 5 °, in a direction away from the catalytic surface. In addition, when seen in the longitudinal direction the spokes can be horizontal unlike the spokes shown in Fig. 2.
As shown in Fig. 1 , a downward air pocket 1 1 can be provided below each spoke, and this air pocket ends in small apertures 1 2, cf. Fig. 2, in the uppermost end of each spoke 10a to 10h in the use position.
A set of basket or net-like lens holders 1 3, 14 can furthermore be secured to the frame. These lens holders are secured to their respective two-armed lever 1 5, 1 6 which are pivotally mounted about a shaft pivot 1 7 through an opening 18 in the end of the frame 6 provided above the legs 8.
It should be noted that these basket or net-like lens holders 1 3, 14 as well as their securing to the frame have not been shown in Fig. 2 for the sake of clarity.
The basket or net-like lens holders 1 3, 14 contain a pair of contact lenses 1 9, 20, respectively. The lens holders 13, 14 are retained in the position shown in Fig. 1 by the force of a spring means not shown, but conven¬ tionally known. The lens holders 13, 14 can be opened by the free ends of the levers 1 5, 1 6 being pressed towards one another against the force of the spring means.
When the apparatus is to be used, the reaction vessel 1 is filled with a 3% solution of hydrogen peroxide H 2 O 2 up to the surface 21 shown. The contact lenses 1 9, 20 are placed in the lens holders 1 3, 14 and immersed into the reaction vessel 1 with the H 2 0 2 -solution, whereafter the cover 3 is screwed on the reaction vessel 1 .
Now the catalyst 9 neutralizes the H 2 O 2 -solution, said solution being contacted with the catalyst 9 through the access apertures 22. The neu¬ tralization goes on, however, very slowly at first because already during the first few seconds oxygen develops vigorously, said oxygen being collected in the air pockets 1 1 and covering the surface of the catalyst 9. In this manner an O 2 -blocking layer is formed on the surface of the cata¬ lyst, and this blocking layer delays the neutralization of the H 2 O 2 -solution in the reaction vessel 1 .
The oxygen confined in the air pockets 1 1 escapes gradually through the small apertures 1 2 in each spoke. The oxygen rises to the surface 21 and escapes from the vessel through the outlet opening 5 or optionally through the gasket 4 provided said gasket has been made oxygen-permeable.
After a suitable period sufficient for obtaining a good disinfecting effect of the contact lenses 1 9, 20, the concentration of H 2 O 2 has dropped so much that the O 2 -blocking of the surface of the catalyst gradually ceases. In this manner the catalyst becomes free with the result that the neutrali¬ zation of the remaining concentration of H 2 O 2 is accelerated. Subsequently, the process continues until the H 2 O 2 -concentration is suffi¬ ciently low and the remaining concentration in the contact lenses 1 9, 20 does not irritate the eyes.
The embodiment of Figs. 3 and 4 differs only from the first embodiment of Figs. 1 and 2 by the spokes 10a to 10Ji being interconnected and extend¬ ing as a helical winding 1 0 rising along an axis which is vertical in the use
position. This helical winding 10 completely surrounds the catalytic element 9.
Therefore the oxygen, O 2 , developed rises along the helical winding 10 and escapes through a small opening 23 positioned in the uppermost end of the helical winding 1 0. Subsequently, the oxygen rises in the same manner as stated above to the H 2 O 2 -surface and escapes through the ventilating opening 5 or optionally through the gasket 4.