CA1052525A - Apparatus and process for disinfection of hydrophilic contact lenses - Google Patents

Abstract

ABSTRACT

Process and apparatus for disinfection of hydro-philic contact lenses by controlled exposure of the lenses to heat. In the apparatus is a compartment formed by a heat storage-transfer combination. The compartment forming combination is heated by means of a heating ele-ment. The heat is transferred to a contact lens carrying case received in the compartment. The heat is maintained at temperatures and for a period of time sufficient to disinfect hydrophilic contact lenses contained in the carrying case.

Description

l~)S'~525 BACKGROU~iD 0~ THE INV NTION

1. Field of the Invention:
Thls invention relates to apparatus for and a process of dislnfecting hydrophillic contact lenses. ~ore particularly, this invention relates to a portable a~para-tus for disinfecting hydrophlllic contact lenses.

2. Description Or the Prior Art:
Hydrophillic contact lenses being water absorbant require daily care by the patlent in order to destroy patho-genic microorganlsms which accumulate on and can contamlnatethe lenses. Daily care, l.e. dlsinfection, is necessary, ror the microorganisms are a potential source o~ eye in~ec-tion if they are not destroyed.
A number Or methods have been suggested ror disinfecting hydrophillic lenses such as, for example, boiling the lenses immersed in a saline solution for at least 10 minutes at ~100C, or chemically treatlng the lenses. Boiling, which requlres the attention Or the patlent is a time consumlng process and the hlgh temperature treatment can, with the passage of time, have adverse affects upon the lens. Che~i-cal treatment requlres the utmost care sin~e a~ter treat-ment the chemicals must be properly and thoroughly ~lushed _ rrom the lens.

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~)5~5Z5 1 In order to destroy the pathogenic microor~anisms, it ls sufficient to disinfect the lens.
The physical requirements for disln~ection are that the ob~ect be heated at a sufficient temperature and for a sufficient time so as to cause the destruction of patho-genic microorganlsms on the lenses.
In U.S. Patent 3,801,278 of Wagner et al, lssued April 2, 1974 an apparatus is disclosed for mass sterili-zatlon of hydrophillic lenses. The apparatus is particu-larly designed for the ophthalmologists and optometrists.
The patent discloses and teaches that the lenses are to be sterilized. The device is not suitable for home use since it is bulky and desi~ned around the needs of the professional who has to treat lenses in bulk. Because the lenses are sterilized the apparatus is not particularly desirable for constant use by a patient who is involved with treating only a pair of lenses. The de~ice further-more employs a mechanical timer for controlling its opera-tion.
U.S. Patent 3,720,402 of Cummins et al, issued May 13, 1973 describes a cleaning device for contact lenses.
The device, as described, cannot effectively be employed for disinfecting since the temperature requirement for disinfecting ls not obtained. The device additlonally depends on a mechanical timing mechanism for its opera-tlon which, if it should not properly function, could result in the evaporation of the cleaning fluid and the concomitant adverse environment for the treated lenses.
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,...... ,1.............. ~ ; " ~ ,. , ~ ;, ' ~05'~525 1 U.S. Patent 3,585,362 issued June 15, 1971 describes an apparatus which depends on the rapid conversion of a quantity o~ water to steam for sterilizing co~tact lenses.
This~ device and others which similarly depend on the ~conversion of water to steam for the treatment of hydro-philic contact lenses must be carefully cared for by the patient in order to avoid the corrosion of metal parts as a result of deposits such as iron, caIcium, chloride ions and the like which ~-ill form if the device is not pro-perly cleaned a~ter each use.
U.S. Patent 3,852,032 of Urbach, issued December 7, 1974, describes a method of sterilization of hydrophilic contact lenses by means of U.V. radiation. In order to avoid embrittlement and disintegration of the p~lymeric material constituting the contact lens, the lens material must contain ultraviolet stabilizers. The method and apparatus described is not universally applicable for -hydrophilic contact lenses since few, if any lenses com-prise U.V. stabilizers.
It is therefore desirable to provide a simple device for disinfecting hydrophilic contact lenses which devlce would be applicable for all types of hydrophilic lenses, does not depend on the production of steam for the tra~1sfer ~f hea~ from th~ ~pp~ratu~ to the lens, is easily carried about in a woman's purse ~r i~-a man's shir~ .. -pocket, and is free of mechanical timing mechanlsms.

SUM~RY OF THE PR~S~NT INVENTION

In accordance with the ~resent ~nvention, there is provided a di~infecting apparatus for destroying patno-genlc microor~anisms ~h~t may be on and about a contact lens. Disinfection ls accomplished by surrounding a contact lens carrylng case containing contact lenses, typically hydrophilic contact lenses, with dry, hot air at temperatures and for at least a per~od of tim~
necessary to destroy pathogenic microorganisms. The apparatus comprises a houslng having a cover and a base.
The cover ls closable relative to the housing. The housing has an opening into which is closely fitted a heat storage-transfer block (heat member) which can be recessed so as to receive a contact lens carrying case.
Upon closing the cover, an insulated compartment ls formed for a contact lens carrylng case. By means of a heating element enclosed in the housing the heat member is heated to a predetermined temperature. The heat ab-sorbed by the heat member is transferred to the carrying case within the compartment at a rate so as to obtain a complete disinfecting cycle of the contact lenses within the carrying case.
The heat member is desirably made from a high den-slty metal which is easily cast, coated and has a high heat capacity as for example; zinc, brass, steel, copper, gray iron and the like. Such a material will absorb the heat and preferably provide a thermal mass in the range of 4 ounces to about 16 ounces and preferably 8 ounces.

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l Up~n obtalning the desired predetermined temperature, the selected metal will continuously release its accumulated heat at a rate and at temperatures so as to cause the interior of a contact lens carrying case to be malntained preferably within a temperature range of from ~80C to about ~100C for at least 10 minutes. In accordance with the invention the disinfectlng cycle is controlled through the selection of materials of which the heat member is constructed, the weight o~ the member, the predetermlned temperature to which the member is heated and the insula-tion surrounding the material. The use of the dense metal having the proper weight will result in the métal inherently acting as the timing mechanism as well as transferring the heat from the heater to the case. If the material and lts weight be such that the absorbed heat is rapidly given up, the interior o~ the carrying case will not be maintained at the disinfecting cycle.
On the other hand, should the metal be exceedingly heavy, the disinfecting cycle will be maintained for an unnecessarily long period of time. Upon the heat member obtaining the predetermined temperature, the heating ele- -ment is deactivated by means of a selectively operable control means. Dlsin~ection will continue since the heat member will continuously release its absorbed heat into the chamber. It is clear that the device does not re- .
quire a timing mechanism since the interior temperature of the carrying case and the length Or time the tempera-turè~ is malntalned is controlled primarJily by proper ~.. ~
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~SZ5'Z5 1 selection of the heat member material and the predeter-mined temperature.
The predetermined temperature is determined by the material of which the heat member is constructed and its size. The temperature should be selected so as to achieve the release of absorbed heat to the carrying case at a rate which will cause the disinfecting cycle to take place from about 10 to about 20 minutes and preferably from about '5 to about 20 minutes.
The weight of the heat member, in the case of it being constructed of zinc, is in the range of about 23 grams to about 248 grams. A smaller heat member will be more sensitive to ambient conditions, whereas a heavier heat member, as indicated above will maintain the disinfecting temperatures for an unnecessarily long period of time.
; The predetermined temperature for a heat member constructed of zinc is about +122C. For heat members constructed of other metals, the predetermined tempera~
ture will be ad~usted accordingly in order to obtain the objectives of the invention.
By employing the device in accordance with this invention, the use of steam for heat transfer is eliminated, one need not employ chemicals for disinfection, a simple portable device is provided and timing means is provided without employment of mechanical timers.

DESCRIPTION OF THE DRAWINGS
-Fig. 1 is a perspective view of th~e preferred embodiment of the invention;

105;~525 .
Fig. 2 is a sectlon view along 2-2 of Fig. l;
~ig. 3 is a section view along 3-3 of Fig. l;
Flg. 4 is a cutaway bo~tom view of the apparatus Or this invention;
Fig. ~ is a kemperature vs. time graph illustrating the temperature-time operation Or the device of this in-vention. `-DESCRIPTION OF THE PREFERRED EMBO~IMENTS

Referring to the drawings, Fig. 1, shows the a~p2ra-tus generally indicated at 10. The apparatus includes a base 12, housing 13 having an upper surface 14 into which an opening 15 is formed. The opening is shaped to receive a bottom portion heat member 16 having a re-cess or well 17. The heat member 16 and recess ~7 are preferably shap-_ in accordance with the shape o~ the con-tact lens carrying case to be received therein. As, illustrated in Fig. 1, the recess is shallow and shaped to receive a carrying case wherein two lenses will lie substantially horizontal with respect to each other.
Typically the-recess wlll be shaped so as to recelve a contact lens carrying case, Should the carrying case be designed so that the lenses lie substantially vertical with respect to each,other, the heat member 16 ~nd recess 17 would be shaped so as to ~orm a well. The housing is provided wlth a suitable closure such as a hinged cover 18. However, the cover can be slidably closed or closable by other methods and means.

~05'~525 ~ In the prererred em~od~ment of thls inventlon, the cover 18 has mounted by any suitable means, such as re-talning elements 39 and 40 a top portion heat member 19 haiin~ recess 20. The top portlon heat member is de-8igned to absorb heat rapldly rrom the bottom heat mem-ber and Sransr r such hea~ to the carry~n~ case and there-~ore ls sultably constructed Or a metal havlng a high thermal conductivlty such as for example alu~inum. The outer rlm 21 of the bottom heat member and.the outer ri~
22 Or the top heat member when the cover is in a closea configuration.meet so as to form a compartment shaped to ~eceive a contact lens carrying case.
As an alternatl~e, heat member 16 can.be constructed 80 as to have a flat upper surface and heat member 19 can be recessed so as to surround the top and slde por-.. . . .. . . .
tlons Or the carrying case.
The rlm ls cut away at 23 and 24 ln order to racill-tate the placement ln and removal Or the carrying case with respect to the recess. A latch 25, latch cover 26.
and catch 27 for the latch is provlded so as to keep the cover or lld 18 ln a secured closed position during the operatlon orthe apparatus. Any other sultable means may be employed in order to secure the cover ln a closed pos.ition during.the oDeratlon of the apparatus.
Heat member 16 formin~ the bottom por~ion o~ the dlsinfectlng compartment ls heated by means of electrical heatlng element 33 whlch ls preferably dlsposed on the .

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lOS;252s 1 underside of said heat member. In the preferred embodi ment of the invention heating element 33 is a ~5 watt heater. However, higher or lower watt sources can be employed.
By means of starter button 28 disposed in the cover 18 ~ manual reset thermostat 32 actuates heating element 33. In order to insure that heating element 33 cannot be actuated while cover or lid 18 is in an open mode~
starter button 28 is not directly connected to manual reset thermostat 32. Upon closing lid 18, button exten-, sion 29 extends into starter button extension apperture ¦ 30 and only upon pressing while the lid is closed does the starter button extension 29 cooperate with actuator 31 of the thermostat 32. In order to prevent the leakage 15, ~ moisture through the apperture 30, said apperture can be suitably covered with a flexible sheet such as a rubber sheet which wouid not hinder cooperation between the bùtton extenslon and the actuator.
Although a manual reset thermostat is preferably employed, other positive temperature coefficient materials can'be employed such as make or break thermostats.
'An indicator element 34 in register with a clear lens 35 and lamp 36 disposed in lamp apperture 37 .
beneath the lens indicates whether the apparatus is in operation.' Other indicator means may be suitably implied ,.
such as, for example, a temperature sensitive meter.
A thermostat 38 preferably an automatic thermostat maintains the indicator lamp 36 after t~he manual reset thermostat deactivates the heating element. After the disinfecting cycle has been completed an~ the apparatus has cooled to a suitable temperature~ thermostat 38 .. ,-:
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1 automatically shuts off lamp 36 thereby indicating that the disinfectîng cycle is complete and the contact lens carrying case containing the lenses can be removed.
In operation, a contact lens carrying case (not shown) typically containing a pair of hydrophilic contact lenses bathed in a saline solution is placed into the bottom portion heat member 16. By means of a male plug 40 the apparatus is connected to a line cord (not sho~n) and thence to a source of electricity. The cover 18 is closed thereby substantially completely enclosing the carrying case in a substantially heat tight co~partment.
The operator presses the starter button 28 which extends through the actuator apperture 30 thereby engaging the actuator 31 of the manual reset thermostat 32. The manual reset thermostat 32 actuates the heating element 33. The heating element 33 heats the heat member 16 until the heat member, which is preferably constructed of ~inc, reaches a temperature of about +122C. The manual reset thermostat 32 thereupon deactivates the heating element 33. The interior of the carrying cas;e is closely surrounded by the heating member and preferably the bottom and side walls of the carrying case are sur-rounded by the bottom portion heating member. The heat members transfer their absorbed heat to the carrying case thereby causing the temperature interior the ~arrying case to rise. The rate of heat transfer which, as ex-plained hereinbefore, is such that the interior of the - . ~

1052~Z5 1 carrying case is maintained for a sufficient time and tem-perature so as to obtain a disinfecting cycle.
In order to indicate that apparatus 10 is in opera-tion, the indicator lamp 36 is automatically turned on upon activation of the heater element 33. When heat mem-ber 16 initially reaches a temperature of about +90C, automatic thermostat 38 closes a switch so as to control the indicator lamp after the manual reset thermostat 32 opens. When the heating member 16 falls to a temperature of about +52C, the indicator lamp 36 is automatically switched off by the thermostat 38 which opens thereby signaling that the lenses have been through a complete disinfecting cycle.
The process as described therefore comprises heating -15 - a contact lens carrying case, containing contact lenses bathed in a salution, by means of substantially dry, hot air i.e., air not heated by means of steam evolving from boiling water. The heat process is maintained at a tem-perature and for a period of time such that the contact lenses interior the case are subjected to a disinfecting cycle. Disinfecting cycle is understood to mean that period of time at the necessary temperatures required to destroy the pathogenic microorganisms on and about the contact lens.
Fig. 5 graphically illustrates the operation in accordance with the invention. Curve 42 represents the temperature-time curve of the heat member 16. Curve 41 represents the temperature-time curve interior the con-tact lens ca-rying case. A~ 'ime z-ro both the interior f~ f ~' , i; :
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lOS'~S25 1 Or the carrying case and the heat member 16 are at about ambient temperature. The heat member 16 ls selected from a material, preferably zinc, and constructed as to size, so as to reach the temperature o~ about +122C in ~rom about 10 to about 30 minutes and preferably about 25 minutes. As the temperature of the heat member 16 rlses, it trans~ers its heat to heat member 19 and to the contact lens carrying case so that the interior o~
the carrying case typically reaches the temperature of about +80C in about 15 minutes. Upon reaching the pre-determined temperature of about ~122C the heating ele-ment is deactivated. The heatlng member thereafter gives up its retalned heat at a rate so as to maintaln the lnterlor of the carrying case at a temperature of be-tween ~80C and about +100C for at least a time requlred to dlsinfect the lenses. Typically the time required is about from;10 minutes and preferably to about 25 minutes. f The temperature of the heat member and the carrying case thereafter slowly drops until the lndicator light shows that the interlor of the devlce has reached a temperature whlch permlts comfortable handllng. In order to insure that the heat member cannot be heated higher than the predetermlned temperature thermal fuse 43 ls employed.

We Claim:

Claims (26)

1. A device for destroying pathogenic microorganisms contaminating a contact lens comprising, in combination, means defining a housing having a base and a cover, said cover being movable in o closed position relative to said housing,said housing having an opening portion shaped to receive a heat storage-transfer well member, said well member adapted to receive and partially surround a contact lens carrying case, said well member and cover when in closed position defining a compartment, means for heating said well member to a predetermined temperature, which heat is transferred by said well member to the contact lens carrying case, said heat transfer being sufficient to raise the interior temperature of a contact lens carrying case received into the well to at least a temperature and time interval sufficient to destroy pathogenic microorganisms contaminating a contact lens and selectively operable control means for actuating and deactivating said heating means.

2. The device of claim 1 wherein the housing and cover are formed of insulating material.

3. The device of claim 2, wherein the well member is shaped so as to surround the bottom and the sides of the contact lens carrying case received therein.

4. A device for disinfecting contact lenses com-prising, in combination, means defining a housing having a base and a cover, said cover being movable into closed position relative to said housing, said housing having an opening portion shaped to receive a heat storage-transfer block member, a heat storage-transfer block member in said opening, said block member adapted to re-ceive a contact lens carrying case, said housing with said block member and cover when in closed position de-fining a compartment, means for heating said block mem-ber to a predetermined temperature which heat is trans-ferred by said block member to the contact lens carrying case received therein to raise the interior temperature of the case to at least a disinfecting temperature, selectively operable control means for actuating and deactivating said heating means, the block member being selected from a material having the property of trans-ferring the absorbed heat to the contact lens carrying case at a rate whereby the disinfecting temperature is maintained for at least a complete disinfecting cycle.

5. The device of claim 4, wherein the block member is recessed so as to substantially surround the bottom and side walls of a contact lens carrying case.

6. The device of claim 4, wherein the predetermined temperature and the block member material is selected so as to maintain the disinfecting temperature interior the contact lens carrying case for at least ten minutes.

7. The device of claim 4, wherein the operable control means automatically deactivates the heating means upon the block member obtaining the predetermined tem-perature.

8. The device of claim 5, wherein the block member material is a dense metal having a substantially high heat capacity.

9. The device of claim 4, wherein the block member material is one of zinc, brass, steel, copper or grey iron.

10. The device of claim 9, wherein-the block member material is zinc.

11. The device of claim 10, wherein the predetermined temperature is about +122°C.

12. The device of claim 4, wherein the operable control is a manual reset thermostat.

13. A device for asepticizing contact lenses com-prising, in combination, means defining a housing having a base and a cover, said cover being movable into closed position relative to said housing, said housing having a top opening shaped to receive a bottom portion heat storage-transfer block member received in said opening, said block member having a recess therein, said cover having mounted on its underside a top portion heat storage-transfer block member having a recess therein whereby when said cover is in closed position said top and bottom block member form a substantially closed compartment adapted to contain a contact lens carrying case, means for heating said bottom portion block member to a pre-determined temperature, which heat is transferred by said block member to the contact lens carrying case so as to raise the interior of a carrying case disposed in the compartment to at least a disinfecting temperature, selectively operable control means for activating and deactivating said-heating means, the bottom member being of a material having the property of transferring the absorbed heat to the upper member and the carrying case at a rate whereby the disinfecting temperature is main-tained interior the contact lens carrying case for at least a complete disinfecting cycle.

14. The device of claim 13, wherein the operable control means automatically deactivates the heating means when the bottom portion block member reaches the predeter-mined temperature.

15. The device of claim 13, further including indi-cator means for indicating the device is in an operating mode and deactivating means for the indicator.

16. The device of claim 15, wherein the indicator means is activated by means of the selectively operable control means and upon deactivation of the selectively operable control means maintained by and deactivated by an automatic control means.

17. The device of claim 16, wherein the selectively operable control means is a manual reset thermostat and the automatic control means is an automatic thermostat.

18. The device of claim 13, wherein the predeter-mined temperature and the block member material is selected so as to maintain an asepticizing temperature for at least ten minutes.

19. The device of claim 18, wherein the lower block member material is a dense metal having a substantially high beat capacity.

20. The device of claim 18, wherein the lower block member material is one of zinc, brass, steel, copper or grey iron.

21. The device of claim 18, wherein the lower block member material is zinc and the upper block member material is aluminum.

22. The device of claim 21, wherein predetermined temperature is about +122°C.

23. The device of claim 14, wherein the manual reset deactivates upon the lower block member obtaining a tem-perature of about +122°C, the automatic thermostat ac-tivates upon the bottom block member obtaining a tem-perature of about +83°C and deactivates when the lower block member obtains a temperature of about +52°C.

24. In a process of disinfecting contact lenses con-tained in a contact lens carrying case, the improvement comprising, heating the contact lens carrying case by means of dry, hot air to a temperature and for a period of time such that the contact lens contained interior the contact lens carrying case is maintained at a disinfecting temperature range for at least a disinfecting cycle.

25. In a process of disinfecting contact lenses con-tained in a contact lens carrying case and bathed in a saline solution the improvement comprising, a. placing the contact lens carrying case con-taining the lenses into a compartment formed substantially by a heat storage-transfer member, said member formed from a dense metal, b. heating the member to a predetermined tem-perature such that the metal will transfer hot air about the contact lens carrying case at a temperature and for a period of time such that the interior of the contact lens carrying case is maintained at a disinfecting tem-perature range for at least a disinfecting cycle and thereafter.

26. A method of disinfecting contact lenses stored in a contact lens carrying case by subjecting the contact lenses to a controlled disinfecting cycle, comprising the steps of: placing the contact lens storage case containing the lenses proximate a heating means; actuating the heating means to elevate the temperature of the contact lenses stored within the storage case; simultaneously causing an indicator means to actuate to provide an indication that the contact lenses are undergoing the controlled disinfecting cycle; automatically deactuating the heating means after a predetermined period of time; and auto-matically deactuating the indicator means as an indication that the disinfecting care cycle has been completed.