Contact lens aseptor

A contact lens disinfector has a molded plastic casing with wells at opposite ends for receiving the respective lenses and the disinfecting solution. Caps are removably threaded onto the casing over the wells. A thermistor heater is embedded in the casing between the wells to provide a low temperature (60.degree. C. -80.degree. C.) heater for the solution for an extended heating cycle, thereby to inhibit deterioration of the lenses due to loss of transparency.

BACKGROUND OF THE INVENTION 
This invention relates to aseptors or disinfectors for small objects such 
as contact lenses and the like. 
Hydrophilic contact lenses, sometimes referred to as soft contact lenses, 
must be periodically disinfected or asepticized. Customarily, this 
asepticizing action is carried out by heating the lenses to a sufficient 
temperature and for a sufficient period of time in a aqueous saline 
solution. Various contact lens sterilizers or asepticizers which have been 
offered for sale accomplished this task. However, many of these units are 
designed to asepticize the lenses quickly, and for that reason they tend 
to apply a relatively high temperature to the lenses for a short period of 
time. 
While the foregoing procedure is seemingly a timesaver to the user, the use 
of high temperatures in the disinfecting process tends to deteriorate the 
lenses. In this regard it has been found that over a period of time the 
lenses tend to become less transparent, thus taking on a cloudy 
appearance. Accordingly, the preferred disinfecting procedure is one in 
which a lesser temperature is used but for a somewhat longer period of 
time. Thus, it appears that while many prior art disinfectors utilize 
temperatures which are near the boiling point of the disinfectant solution 
(in the order of 100.degree. C.) the preferred "heat history" of the 
disinfecting cycle is one in which the temperature is in the range of 
60.degree. C.-80.degree. C. 
OBJECTS AND SUMMARY OF THE INVENTION 
An object of this invention is to provide a contact lens aseptor which 
reduces the temperature or "heat history" of the lenses during the 
disinfecting cycle, thereby to avoid deterioration of the lenses as to 
their transparency. 
A further object of this invention is to provide an aseptor of the type 
stated which is compact and is relatively inexpensive to fabricate and at 
the same time embodies a heater which limits the disinfecting temperature 
to well below the boiling point of the disinfecting solution. 
In accordance with the foregoing objects the aseptor comprises a casing 
having a pair of wells for receiving disinfecting solution, each well 
having an opening at the surface of the casing, a removable liquid-tight 
cover across each opening, means associated with each well respectively 
for providing indicia as to right or left eye contact lens, and an 
electrical heater embedded in said casing for supplying heat to the wells, 
said heater being of the type having a resistance that increases as a 
function of temperature to limit the maximum operating temperature of the 
heater. 
The operating temperature of the heater is limited so that the operating 
temperature of the disinfecting solution in the wells is about 60.degree. 
C. to about 80.degree. C. In a preferred embodiment of the invention, the 
heater comprises a thermistor.

DETAILED DESCRIPTION 
Referring now in more detail to the drawing there is shown a disinfectant 
unit or aseptor 2 comprising a one piece casing 4 of any suitable plastic 
material, such as a thermosetting resin. The casing 4 is of cylindrical 
form and has a number of axially spaced ribs 6 in the form of cylindrical 
rings and which serve as cooling fins that permit handling of the casing 4 
when the latter is hot, as will be presently more fully described. The 
casing 4 furthermore has opposite axial ends 8,10, and at each of the ends 
8,10 there is a recess or well 12,14 of substantially hemispherical shape. 
The wells open up at the surfaces of the casing that are at the ends 8,10. 
For closing off each well 12,14 there is a threaded cap 16,18. Each cap 
16,18 has an annular threaded skirt for engagement with external threads 
20,22 on the casing 4 adjacent to the ends 8,10. The casing 4 or the caps 
16,18 may each include an annular gasket 24 to provide a seal between the 
cap and the casing. The cap 18 is molded with a letter L while the cap 16 
is molded with an R whereby suitable indicia are provided for indicating 
whether the right or left eye contact lens is in the associated well 
12,14, as the case may be. Furthermore, the caps 16,18 may be formed with 
axial ribs 26 on the exterior of the cap skirts to facilitate manipulation 
of the caps. Integrally molded with and thus embedded in the casing 4 is a 
resistance heater 28 of the type having a resistance that increases as the 
function of temperature to limit the maximum operating temperature of the 
heater and to prevent a "runaway" condition. Such a heater 28 may be a 
thermistor. Devices of this type are known in the art and are 
characterized in that there is a change in the resistivity of a 
semi-conductor upon a change in its temperature. The thermistor heater 28 
is fully embedded within the casing 4 and is axially disposed between the 
wells 12,14, as best shown in FIG. 4. The heater 28 includes insulated 
conductors in the form of a power line cord 30 that extends through the 
casing 4 and outwardly thereof for connection to a plug 32. The plug 32 is 
conventional and is to be plugged into a power line receptacle. 
The operation of the unit 2 is apparent. Suffice to say, however, that the 
wells 12,14 may be filled with disinfecting solution and the contact 
lenses 34,36 deposited therein and with the caps 16,18 threaded in place 
as shown in FIG. 4. The heater 28 is of a type that gradually increases 
the temperature of the disinfecting solution in each well to about 
60.degree. C.-80.degree. C., which constitutes a heat or temperature 
plateau that is maintained throughout the heating cycle. The temperature 
of the disinfecting solution should reach 80.degree. C. for at least 10 
minutes in order to provide a satisfactory disinfecting action.