Note: Descriptions are shown in the official language in which they were submitted.
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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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 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.
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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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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
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Fig. 1 is a perspective view of th~e preferred
embodiment of the invention;
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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.
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~ 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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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
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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
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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
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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:
