Patent Publication Number: US-8113341-B2

Title: Contact lens case

Description:
RELATED APPLICATION (PRIORITY CLAIM) 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/888,605, filed Feb. 7, 2007, which is hereby incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     The present invention generally relates to contact lens cases. 
     U.S. Pat. No. 3,770,113 (Thomas) discloses a prior art contact lens storage and disinfection cup system  10 . The Thomas system is illustrated in  FIG. 1  of the present application, and utilizes a planar central stem  12  that engages a cap  13 . The stem  12  has dome features  14  on each side of the stem  12  and hinged containment cages  16  which pivot into a closed position over the domes  14  and parallel to the planar stem  12 . Subsequent commercial cup disinfection and storage systems have generally followed the same layout with only minor differences in the ribbing of the cages or the form of the dome used to receive the contact lens. This layout of the lens retaining components has withstood the test of time in part due to the efficiency in which it utilizes space available within the cup. Typically, contact lens solution makers have settled upon the use of 10 cubic centimeters (cc&#39;s) of solution within the cup for purposes of disinfection or hydration. This volume of fluid may have been driven by the geometry of the cup design disclosed in the &#39;113 patent in order to assure that lenses were fully immersed in solution; nevertheless the 10 cc fluid volume has become standard within the lens care industry and as a consequence, subsequent lens cup designs have been driven by the need to keep contained contact lenses fully immersed in 10 cc&#39;s of fluid. 
     Users of these lens cases generally find it easier to deliver their lenses to the dome feature  14  instead of the cage  16 . This is in part due to the tendency of the damp lens to adhere the dome surface  14  which has more surface area than the cage  16  and more closely resembles the shape of a human eyeball. Since contact lens wearers typically grasp the lens by its convex outer surface to remove it from their eye, the dome  14  provides a ready receptacle without having to change one&#39;s grasp on the lens. Contact lens wearers also show preference for larger domes and cages as opposed to smaller ones in which fingers must be more dexterous in order to place or retrieve lenses. This user preference may also be driven by an older population of contact lens wearers who may lack the dexterity of younger lens users. 
     Although it would prove more convenient to the user to reverse the layout of the design disclosed in the &#39;113 patent by providing the dome  14  on the more accessible hinged member  16 , this has not been commercially pursued primarily due to the inefficient utilization of space and volume presented by such a layout. Direct reversal of the cup system layout disclosed in the &#39;113 patent would require a larger diameter cup cylinder  18  to receive the basket and stem assembly which in turn would require use of more than the standard  10  cc&#39;s of lens care solution to assure immersion of the lenses. 
     Another method to facilitate such reversal would be to reduce the diameter and depth of the lens cage, but this would be judged as user unfriendly by a large portion of lens wearers who find smaller lens cages difficult to use. Typically, the inner base diameter of commercial contact lens cases range from 0.70 inches to 0.80 inches, and this is what users are accustomed to using. 
     The contact lens case configuration  10  disclosed in the &#39;113 patent includes a latching mechanism  20  for holding the hinged members  16  closed in order to retain the lenses. As shown in  FIG. 1 , the latching mechanism  20  disclosed in the &#39;113 patent consists of latch arms  22  which are disposed on the hinged members  16  and which are configured to engage bottom surfaces  24  of the central stem member  12 . Many subsequent contact lens case systems have followed the same approach and have similar latching mechanisms. However, latches such as that which is disclosed in the &#39;113 patent have a tendency to cut lenses that are not properly aligned when the hinged member is moved into the closed, latched position. 
     Most contact lens are made of plastic, using a molding process. The molding process used to produce plastic lens cases is generally paced by the speed at which heat can be removed from the molten plastic resin once it has been injected into the mold. Plastic resin must be sufficiently cooled and therefore hardened to prevent distortion upon ejection or handling. Overly thick sections of plastic slow down the molding process because they require more time to cool. In some instances, thick sections can warp or suffer from surface distortions known as sink, in which the molten plastic within the thick section pulls the hardened outside skin inwards as the molten resin shrinks during cooling. Makers of contact lens storage and disinfection cases based upon the lens case configuration disclosed in the Thomas &#39;113 patent configuration have long suffered extended molding times and sink in parts as a result of the large plastic mass necessarily contained within the back-to-back dome configuration. The optimum dome shape and size cannot be efficiently produced with this layout. Precise configurations for the dome have proven impossible to mold on a reliable basis. Attempts to create a dome form from a series of contoured ribs or place apertures within the dome&#39;s center have generally resulted in domes that fail to present sufficient surface area to hold onto the lenses placed there or domes that will not release lenses for treatment once immersed in solution. These compromised domes may not preferentially retain lenses once the stem assembly has been withdrawn from its solution bath. 
     SUMMARY 
     An embodiment of the present invention provides an improved contact lens case which includes domes that are provided on hinged members. Preferably, the contact lens case is configured to efficiently utilize space and volume such that no more than 10 cc&#39;s of contact lens solution are required to disinfect contact lenses in the case. Additionally, preferably the contact lens case is configured such that it can be easily molded and assembled. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The organization and manner of the structure and operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings wherein like reference numerals identify like elements in which: 
         FIG. 1  is an exploded view of the prior art contact lens case configuration disclosed in U.S. Pat. No. 3,770,113 (Thomas); 
         FIG. 2  is a top perspective view of certain components of a contact lens case configuration which is in accordance with an embodiment of the present invention, showing a stein, cages, and domes which are provided on hinged members; 
         FIG. 3  is an enlarged perspective view of a catalyst which may be used in association with the contact lens case configuration shown in  FIG. 2 ; 
         FIG. 4  is similar to  FIG. 2 , but shows the stem engaged with a cap, and the catalyst positioned on the end of the stem, showing one of the hinged members swung down; 
         FIG. 5  is similar to  FIG. 4 , but shows both of the hinged members swung up and latched in place relative to the stem; 
         FIG. 6  is a cross-sectional view taken along line  6 - 6  of  FIG. 5 ; 
         FIG. 7  is a perspective view showing the lens case closed with its cap on; 
         FIG. 8  is a cross-sectional view taken along line  8 - 8  of  FIG. 7 ; 
         FIG. 9  is a perspective view of the lens case, showing one of the hinged members in the open position; 
         FIG. 10  is a cross sectional view, taken along line  10 - 10  of  FIG. 9 , showing a close up of the latch mechanism within the lens case in both open and closed positions; 
         FIG. 11  is a perspective view of the stem showing the cylindrical hinge receptacles and an internal detent cam surface; 
         FIG. 12  is a top perspective view of a cap of the lens case, shown alone for clarity; 
         FIG. 13  is a view of the cylindrical hinge receptacle of a stem receiving the planar hinge pin of a cross sectioned hinged member into its slot; 
         FIG. 14  is a perspective view of a hinged member showing its opposing planar hinge pins and slot interruption; 
         FIGS. 15-17  are side views of a contact lens case which is in accordance with a preferred embodiment of the present invention; 
         FIG. 18  is a view of the contact lens case shown in  FIGS. 15-17 , depicting the contact lens case opened, with its cap disengaged from its cup; 
         FIG. 19  is a rear view of a hinged member of the contact lens case shown in  FIGS. 15-18 ; 
         FIG. 20  is a perspective view of the hinged member shown in  FIG. 19 ; 
         FIG. 21  is a top view of the hinged member shown in  FIG. 19 ; 
         FIG. 22  is a bottom view of the hinged member shown in  FIG. 19 ; 
         FIG. 23  is a perspective view of a stem component of the contact lens case shown in  FIGS. 15-18 ; 
         FIG. 24  is a side view of the stem component shown in  FIG. 23 ; 
         FIG. 25  is a bottom view of the stem component shown in  FIG. 23 ; 
         FIG. 26  shows the position of cam followers when the hinged members of the contact lens case of  FIGS. 15-18  are in the closed position; 
         FIG. 27  shows the position of cam followers when the hinged members of the contact lens case of  FIGS. 15-18  are in the open position; 
         FIG. 28  shows the hinged members of the contact lens case of  FIGS. 15-18  isolated, with one in the open position and one in the closed position; 
         FIG. 29  is a top view of the cap of the contact lens case shown in  FIGS. 15-18 ; 
         FIG. 30  is a bottom perspective view of the cap of the contact lens case shown in  FIGS. 15-18 ; 
         FIG. 31  is a top perspective view of a gasket component of the contact lens case shown in  FIGS. 15-18 ; 
         FIG. 32  is a bottom perspective view of the gasket shown in  FIG. 31 ; 
         FIG. 33  is a top perspective view of a plug component of the contact lens case shown in  FIGS. 15-18 ; 
         FIG. 34  is a bottom perspective view of the plug shown in  FIG. 33 ; 
         FIG. 35  is a view which shows the notches and ramps of cam surfaces which are provided on the face of receptacles on the stem of the contact lens case shown in  FIGS. 15-18 ; and 
         FIG. 36  is a cross-sectional view of the cap assembly of the contact lens case which is shown in  FIGS. 15-17 . 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS 
     While this invention may be susceptible to embodiment in different forms, there is shown in the drawings and will be described herein in detail, a specific embodiment with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that as illustrated. 
       FIG. 7  illustrates a contact lens case  40  which is in accordance with an embodiment of the present invention. The contact lens case  40  includes a central stem  42  on which is disposed two back-to-back cages  44  (only one of the cages is visible in  FIG. 7 , but see also  FIGS. 2 ,  4  and  6 ). The stem  42  is engaged with a cap  46 , and a catalyst  48  is engaged with the stem  42  opposite the cap  46 . The cap  46  engages the top  50  of a cylindrical cup  52 , thereby forming an enclosed contact lens case. 
       FIG. 2  shows the stem  42  disengaged from the cap  46 . As shown, the stem  42  is planar and has two, back-to-back cages  44  disposed thereon. The cages  44  may be engaged with the stem  42  in a snap-fit arrangement. Alternatively, the cages  44  may be integral with the stem  42  (for example, the stem  42  and cages  44  may be a single, plastic molded piece). Regardless, preferably the cages  44  are positioned in back-to-back orientation, with their convex sides  54  facing each other. Preferably, one end  56  of the stem  42  is configured for engagement with the inside of the cap  46 , while the opposite, distal end  58  of the stem  42  is configured to receive a catalyst  48 . To that end, indentations  60  may be provided on the stem  42 , near its distal end  58 , for receiving and retaining a catalyst  48 .  FIG. 3  illustrates one possible shape of the catalyst  48  which can be used, and  FIGS. 4 ,  5  and  7  illustrate the catalyst  48  engaged with the stem  42 . The catalyst will be described in more detail later hereinbelow. 
     As shown in  FIGS. 4 ,  5  and  7 , hinged members  62  are engaged with the stem  42  and each of the hinged members  62  includes a dome-shaped portion  64  for retaining contact lenses thereon. The hinged members  62  are preferably non-planar (see  FIG. 6  which provides a cross-sectional view taken along line  6 - 6  of  FIG. 5 ) which allows the domes  64  to be provided on the hinged members  62  rather than having to be on the stem  42 , and allows the use of deep larger diameter, back-to-back cages  44  on the stem  42 , without having to resort to using more than 10 cc&#39;s of fluid to immerse contact lenses that are disposed on the domes  64 , between each of the domes  64  and a respective cage  44 . Each of the hinged members  62  is cylindrically-curved, having a cylindrically-curved shell form in which the axis of its curve is approximately parallel to the central axis of the central planar stem member  42 . Specifically, the central axis of each lens cage is disposed parallel to the geometric plane described by the stem  42 . Additionally, the central axis of pivoting for each hinged member  62  is perpendicular to the geometric plane described by the stem  42 . 
     Each hinged member  62  is configured to mount and pivot upon fixed hinge pin receptacles  66  formed upon a common center opposite one another on each side of the planar stem  42 . Small inward facing pin structures  70  are provided on the domed hinged members  62  to serve as hinge pins which mount and pivot within the hinge pin receptacles  66  formed on the planar stem  42 . As such, when a hinged member  62  is pivoted open as shown in  FIGS. 2 and 4 , the dome  64  of the hinged member  62  becomes exposed, ready to receive a contact lens. As shown in  FIGS. 4 and 8 , preferably the cap  46  is generally shaped flat on its top in order to sit stable, inverted on a table surface while lenses are being delivered for disinfection or removed after disinfection. Once a contact lens is positioned on the dome  64 , the hinged member  62  can be pivoted closed, such that its dome  64  and the respective cage  44  on the stem  42  effectively mate, retaining a contact lens therebetween.  FIG. 4  shows the stem  42  engaged with the cap  46 , a catalyst  48  on the end  58  of the stem  42 , and one of the hinged members  62  pivoted down, thereby exposing the dome  64  on the hinged member  62  (and a contact lens, if a contact lens were on the dome  64 ).  FIG. 5  shows both hinged members  62  pivoted closed, and  FIG. 7  shows both hinged members  62  pivoted closed, and the cap  46  engaged with a cylindrical cup  52 . As shown in  FIG. 2 , each of the hinged members  62  preferably has a right/left indicator  72  ( FIG. 2  only shows the hinged member  62  meant to be associated with the contact lens for the right eye), so that a user knows which contact lens is supposed to be engaged with that particular dome. Similarly, while  FIG. 17  shows one of the hinged members  62  including the indicia “L”, thereby indicating to the user that that particular hinged member  62  is meant for use with the contact which is placed in the left eye, it should be understood that preferably the other hinged member  62  includes the indicia “R.”, thereby indicating to the user that that particular hinged member  62  is meant for use with the contact which is placed in the right eye. 
     As shown in  FIG. 4 , for example, the fixed hinge elements  62  on the planar stem  42  are cylindrical in nature, each with slot interruptions  74  located  180  degrees from one another in a plane parallel to the center line of the planar stem  42  to allow flushing and drainage and avoid trapping fluid while in an upright or inverted position. Additionally, as shown in  FIG. 2 , preferably an internal vent port  99  is provided at the base  98  of the stem  42 . 
     As shown in  FIG. 14 , a second potential hinging mechanism  75  for hinging employs inwardly opposed planar hinge pins  77  upon element  62  that are inserted as shown in  FIG. 13 , into cylindrical receptacles  79  provided upon stem  42 . As shown in  FIG. 9 , cylindrical receptacles  79  are positioned perpendicular to the plane of stem  42  and share a common axis with one another on opposite sides of stem  42 . Receptacles  79  each have aligned receiving slots  85  positioned to allow insertion of opposed hinge pins  77  into an inner cylindrical bore  88 .  FIG. 13  shows how the planar hinge pins  77  of element  62  are inserted into the receiving slots  85 . Assembly of the domed hinged member  62  utilizes a snap together method with retention of the planar hinge pins  77  being assured by means of the hinge pin retention ledge  87  shown in  FIG. 10 . Retention ledges  87  result from a gap between tapered ends of opposed hinge pins  77  that is smaller than the width between the bottoms of adjacent receiving slots  85 . Slots  85  in hinge receptacles  79  provide for drainage of fluid from within each hinge receptacle structure while the small surface area of planar hinge pins  77  remaining in contact with the cylindrical interior of hinge receptacles  79  serve to both facilitate this drainage and minimize fluid retention within the hinge assembly due to capillary attraction. 
     As discussed in the background section, latching mechanisms commonly used to hold the hinged members closed in order to retain lenses have often followed the example demonstrated by the Thomas &#39;113 patent. These latches however, have a reputation for cutting misplaced lenses and so it is desirable to utilize a remote latching mechanism. One example of such a mechanism is disclosed in U.S. Pat. No. 4,807,750. The lens case  40  disclosed herein also utilizes a latch mechanism  76  to hold each hinged member  62  closed and prevent lens damage. As shown in cross section in  FIG. 10 , the latch mechanism  76  may comprise a feature located within each pair of cylindrical hinge receptacles  79  which supports a detent cam surface  81  shown in  FIG. 1 , positioned to engage at least one planar hinge pin  77  of each hinged member  62  and thereby hold the hinged member  62  in a closed position. Preferably, the same detent cam  81  is provided for each hinged member  62 . 
     As shown in  FIG. 9 , the latch mechanism  76  also functions to hold the hinged members  62  open. Specifically, as a hinged member  62  is pivoted open, the planar hinge pin tip  83  rides across detent cam surface  81  and seats on the other side of detent cam surface  81 . The detent cam surface  81  and tip  83  of planar hinge pin  77  are configured such that in either position—whether the hinged member  62  is in the open or closed position—the hinged member  62  tends to stay in that position unless intentionally pivoted by a user. Movement of both hinged members  62  from an open or closed position to the opposite position causes tip  83  to ride over cam surface  81  urging the attached planar hinge pin  77  outward over cam surface  81  forcing it away from its opposing hinge pin. Once tip  83  arrives on the other side of cam surface  81  in the new open or closed position, tip  83  springs back to its original location and distance from its opposing planar hinge pin. This spring action which allows tip  83  to traverse over cam surface  81  and return to its original position on hinged member  62  results from elastic deformation of hinged member  62 . Slot interruptions  74  (see  FIG. 14 , for example) assist in keeping deformation stresses resulting from traversing cam surface  81  within the elastic deformation limits of hinged member  62  and below the point of permanent plastic deformation. This detenting feature is desirable in order to facilitate delivery of lenses to the domes  64  and to prevent movement of the hinged dome  64  during retrieval of a disinfected lens. 
     Preferably, the abutting mating faces of each cage  44  and its respective domed hinged member  62  are preferably curved to match one another (see  FIG. 6 ). An assembly of the planar central stein  42  with back-to-back lens cages  44  and mating curved domed hinged members  62  on either side results in a package that does not require as large a cup diameter to accommodate the internal components as would be required if the cages and domes were instead to be provided as having flat faces. Preferably, the case is configured such that use of curved, dome-carrying hinged members  62  allows a desirable lens cage inner base diameter of 0.75 inches to be employed without losing full lens immersion with 10 cc&#39;s of lens solution. 
     Making the dome  64  an integral, thin-walled and continuous element of the hinged member  62  allows a precise dome form to be quickly molded in a repeatable reliable manner without distortion or sink. Domes formed in this manner can be designed to optimize features necessary for preferential retention of lenses during placement and after disinfection or storage. 
     Contact lens cases following the contact lens case configuration disclosed in the Thomas &#39;113 patent have long been used with Hydrogen Peroxide lens disinfection solutions. These solutions must be broken down by metal or organic catalyst means into water and Oxygen in order to neutralize the strong oxidizing agent prior to insertion of treated lenses within the eye. Regardless of the mechanism used to neutralize the Hydrogen Peroxide, evolved Oxygen gas must be vented off to avoid building excessive pressure within the lens case. Pressures exceeding 100 psi are possible within the small volume of a cup type lens case. The mechanism to relieve this pressure must flow only one way in order to prevent intrusion of contaminants or organisms from outside the lens case. Means to provide one way pressure relief are disclosed in U.S. Pat. Nos. 4,956,156 and 5,250,266, and these two patents are hereby incorporated herein by reference in their entirety. These venting systems require an elastomeric membrane having either a precise hole or slit through which excess pressure can be vented in a controlled manner. It is also desirable to have a seal at the cap to cup interface in order to contain fluids within the system and exclude contaminants or organisms. 
     As shown in  FIG. 8 , the contact lens case  40  disclosed herein utilizes a pressure venting mechanism, such as a vent membrane  80 , to relieve excess pressure through a vent notch  103  in the cap  46 , as well as a sealing means, such as a sealing gasket  82  portion of the vent membrane  80 , at the cap-to-cup interface. As shown in  FIG. 8 , the cap  46  includes a plug  105  having a post  107  for sealing of the vent notch  103 . Specifically, the membrane  80  provides a vent hole  109  in which the post  107  becomes disposed when the cap  46  is screwed on to the top  50  of the cup  52 . When venting takes place, the membrane  80  moves away from the post  107  creating a gap, and venting then becomes possible through the vent notch  103  in the cap  46 . 
     As shown in  FIG. 8 , the vent membrane  80  and sealing gasket  82  need not be separate pieces. They can be created simultaneously during the cap&#39;s molding process in which, as shown in  FIG. 12 , a thermoplastic elastomer  91  is overmolded on the plastic cap structure  46  such that the thermoplastic elastomer  91  becomes effectively integral with the gasket  82  and vent valve  80 . As such, an integrally molded cap gasket and elastomeric exterior cap surface are provided, as well as an integrally molded vent mechanism and elastomeric exterior cap surface. Preferably, the thermoplastic elastomer  91  covers the exterior surface of the cap  46  and provides corners  93  to enhance wet grip and tactile feel. Such an approach (i.e., molding the thermoplastic elastomer  91  such that the thermoplastic elastomer becomes effectively integral with the gasket  82  and vent valve  80 ) eliminates a need to procure or assemble these two separate components to the cap  46 . Part count is reduced by this means and the assembly process is simplified through elimination of two handling and assembly stations for both parts. Additionally, when using a separate relief valve as described in U.S. Pat. Nos. 4,956,156 and 5,250,266, it is necessary to assemble the planar stem component to the cap in a very rigid manner such as by welding in order to assure sufficient sealing of the valve&#39;s perimeter to the opposing cap and stem surfaces. When using a separate gasket it may also be necessary to retain the gasket by providing a flange feature on the stem&#39;s mount. When the valve and gasket are overmolded in place, as shown in  FIG. 8 , retaining and sealing features are no longer required to be provided between cap and stem mount, and simpler less rigid means to retain the stem to the cap can be utilized. A welding station for instance, could also be eliminated from the assembly process. 
     Contemplated herein also is a redesign of a reaction catalyst that may be attached to the distal end  58  of the planar stem  42 . Companies such as Bausch and Lomb (easySEPT®), CIBA Vision Corporation (AOSept®) and Sauflon Pharmaceuticals Inc. (OneStep®) each offer Hydrogen Peroxide lens disinfection cup systems having Platinum based catalyst to break down the disinfectant. AMO (Oxysept®) (a spin-off from Allergan) and CIBA Vision (Blue Sept®) offer Hydrogen Peroxide systems which utilize tablets of catalase enzyme to break down the disinfectant. Those systems having the metal-based catalyst all use similar disk like catalytic elements generally cylindrical in form with vertical ribbing and having less height than the diameter of the circle they would fit into. From a user standpoint, these cylindrical forms if attached to the distal end of the stem tend to obstruct users delivering and retrieving their lenses. The catalyst redesign proposed here, and illustrated in  FIG. 3 , provides a catalyst  48  which is somewhat elliptical rather than round in form with the short side  84  of the elliptical form aligned with the hinged members  62  (see  FIG. 4 ), and the long side  86  of the elliptical form being perpendicular to the hinged members  62 . This orientation helps assure that the catalyst  48  does not inhibit user access to the domed surfaces  64 . Height of this reconfigured catalyst would not be appreciably different from existing catalysts in the market place, the amount of active surface area and its orientation being the most important factors in determining final catalyst design. 
     Significant features of the contact lens case  40  disclosed hereinabove may include, but may not be limited to: 
     1. Cylindrically curved mating surfaces on the lens cage and pivoting dome structures to receive lens. 
     2. Large lens cage inner base diameter of 0.75 inches resulting from use of cylindrically curved mating surfaces of lens cage and dome structure. 
     3. Larger properly shaped dome structures to better match lenses. 
     4. Snap together assembly of hinged dome structure to planar stem. 
     5. Remote latch to hold hinged member closed. 
     6. Remote latch to hold hinged member both open and closed. 
     7. Pressure venting mechanism. 
     8. Integrally molded vent mechanism. 
     9. Integrally molded vent mechanism and cap gasket. 
     10. Integrally molded vent mechanism, cap gasket and elastomeric exterior cap surface. 
     11. Redesigned catalyst to improve user access to lenses. 
     12. The cap has a flat top which allows it to sit upright for improved user access (compare to the cap design of the Thomas &#39;113 patent (see  FIG. 1  of the present application) and AC Sept® type cup). 
     13. Drain features in hinge structure. 
       FIGS. 15-18  illustrate a contact lens case  140  which is in accordance with a preferred embodiment of the present invention. The contact lens case  140  is very similar to the contact lens case  40  previously described, and so only the differences will be discussed in detail. Like the contact lens case  40  previously described, the contact lens case  140  includes a stein  142  that has back-to-back cages  144  thereon, hinged members  162  that have domes  164  thereon, and a cup  152 . The contact lens case  140  also includes a cap  146  which is part of a cap assembly (described in more detail later hereinbelow), and which engages the top  150  of the cylindrical cup  152 , such as in a threaded engagement, thereby providing that the lens case  140  is an enclosed structure. A catalyst is engaged with the stem  142  opposite the cap  146 , and the catalyst may be a conventional catalyst or a catalyst  48  such as is shown in  FIG. 3  and which has been described hereinabove. 
     As shown in  FIG. 23 , much like the stem  42  previously described, the stem  142  of lens case  140  has two, back-to-back cages  144  disposed thereon. The cages  144  may be engaged with the stem  142  in a snap-fit arrangement. Alternatively, the cages  144  may be integral with the stem  142  (for example, the stem  142  and cages  144  may be a single, plastic molded piece as shown in the figures). Regardless, preferably the cages  144  are positioned in back-to-back orientation, with their convex sides  154  facing each other. 
     Preferably, one end  156  of the stem  142  is configured for engagement with the inside  157  of the cap assembly  146 . Specifically, the end  156  of the stem  142  may provide a square-like shape profile which inserts in a corresponding recess  159  defined by an extended square wall  177  on the inside surface  157  of the cap assembly  146 . As shown in  FIG. 23 , the end  156  of the stem  142  may provide a plurality of protrusions  161  which insert in corresponding apertures  163  formed in the square wall  177  on the inside surface  157  of the cap assembly  146 , in a snap-fit engagement. 
     Preferably, the opposite, distal end  158  of the stem  142  is configured to receive the catalyst  48 . To that end, as shown in  FIG. 23  fingers  165  having indentations  160  may be provided on the stem  142 , near its distal end  158 , for receiving and retaining the catalyst  48 . 
     As shown in  FIGS. 15-18 , hinged members  162  are engaged with the stem  142  and each of the hinged members  162  includes a dome-shaped portion  164  for retaining contact lenses thereon. The hinged members  162  are preferably non-planar (see  FIGS. 21 and 22  which provides top and bottom views of one of the hinged members, with the other hinged member being virtually identical, but for a different indicia to indicate the other eye) which allows the domes  164  to be provided on the hinged members  162  rather than having to be on the stem  142 , and allows the use of deep larger diameter, back-to-back cages  144  on the stem  142 , without having to resort to using more than 10 cc&#39;s of fluid to immerse contact lenses that are disposed on the domes  164 , between each of the domes  164  and a respective cage  144 . Each of the hinged members  162  is cylindrically-curved, having a cylindrically-curved shell form in which the axis of its curve is approximately parallel to the central axis of the central planar stem member  142 . Specifically, the central axis of each lens cage is disposed parallel to the geometric plane described by the stem  142 . Additionally, the central axis of pivoting for each hinged member  162  is perpendicular to the geometric plane described by the stem. 
     Each hinged member  162  is configured to mount and pivot within fixed hinge pin receptacles  179  which are provided upon a common center opposite one another on each side of the stem  142 . To this end, small inward facing pin structures  177  are provided on support ears  205  of the domed hinged members  162 , and these pin structures  177  mount and rotate within the hinge pin receptacles  179  formed on the stem  142  as the hinged members  162  are being opened and closed. As shown in  FIG. 23 , the cylindrical receptacles  179  are positioned perpendicular to the plane of stem  142  and share a common axis with one another on opposite sides of stem  142 . The receptacles  179  each have aligned receiving slots  185  positioned to allow insertion of the hinge pins  177  into an inner cylindrical bore  188  in the receptacles  179 . 
     Much like as with the contact lens case  40 , the hinge pins  177  are configured to snap into the pin receptacles  179 . Compared to the hinge pins  77  of the contact lens case  40 , the hinge pins  177  of the contact lens case  140  have been rotated  90  degrees (compare pin  77  as shown in  FIG. 14  to pin  177  as shown in  FIG. 28 ) on their common axis such that when the hinged members  162  are installed, they are already in the natural closed position (as shown in  FIGS. 15-18 ). This saves time during assembly and simplifies the process by eliminating any requirement to subsequently fold the hinged members  162  into their closed position after installation. This planar hinge pin orientation also serves to add extra resistance beyond the snap in feature against a hinged member  162  being accidentally pulled from its socket  179  while in an open position, since the planar hinge pin  177  is traverse to its receiving receptacle  179  instead of being in line with it. 
     As such, when a hinged member  162  is pivoted open, the dome  164  of the hinged member  162  becomes exposed, ready to receive a contact lens. As shown in  FIGS. 15-18 , much like the cap  46  previously described, preferably the cap assembly  146  of lens case  140  is generally shaped flat on its top in order to sit stable, inverted on a table surface while lenses are being delivered for disinfection or removed after disinfection. Once a contact lens is positioned on the dome  164 , the hinged member  162  can be pivoted closed, such that its dome  164  and the respective cage  144  on the stem  142  effectively mate, retaining a contact lens therebetween. As shown in  FIGS. 16 and 17 , each of the hinged members  162  preferably has a right/left indicator  172 , so that a user knows which contact lens is supposed to be engaged with that particular dome. 
     With regard to a detention feature (i.e., a feature for retaining the hinged members  162  in either the open or the closed position), for better control and reliability, each hinged member  162  not only has a pin  177  but also cam followers  191  which are provided transverse to each planar hinge pin  177 . The cam followers  191  provide a cam action with regard to a hinge pin cam surface  181  which is on the face  167  of each cylindrical receptacle  179 . Compared to the cam surface  81  which is provided on the contact lens case  40  previously described, the cam surface  181  of the lens case  140  is provided on the cylindrical face  167  of each cylindrical receptacle  179 , thereby positioning each feature further from each hinge pin&#39;s rotational axis  169  (see  FIG. 19 ). This allows more tolerance for variation of both the cam followers  191  and the hinge pin cam surface  181 . Moving further from the rotational axis also provides better mechanical advantage for interacting detenting elements to retain hinged members  162  in both open and closed positions. 
     Each hinge pin cam surface  181  consists of a plurality of “V”-shaped cam notches  183 , including a “hold open” cam notch  201  and “hold closed” ramps  203 . As a hinged member  162  is pivoted open, the cam surfaces  191  ride across the “hold closed” ramps  203  into the “hold open” cam notch  201  (see  FIGS. 27 and 35 ). Regardless of whether the hinged member  162  is in the open or closed position, the hinged member  162  tends to stay in that position unless intentionally pivoted by a user. Movement of both hinged members  162  from an open or closed position to the opposite position causes the cam followers  191  to ride over a ramp of the cam surface  181 , urging the cam followers  191  outward, forcing the ears  205  of the hinged members  162  away from each other. Once the cam followers  191  arrive in a notch, the ears  205  spring back to their original location and distance from each other. Spring action to allow the cam followers  191  to traverse over the ramps of the cam surface  181  and travel into notches of the cam surface  181  results from elastic deformation of the ears  205  of the hinged members  162 . Slot interruptions  174  on the hinged members  162  assist in keeping deformation stresses resulting from traversing cam followers  191  within the elastic deformation limits of hinged member  162  and below the point of permanent plastic deformation. This detenting feature is desirable in order to facilitate delivery of lenses to the domes  164  and to prevent movement of the hinged dome  164  during retrieval of a disinfected lens. 
     Because the final location of the hinged members  162  when open occurs in space and is not dictated by any other structure, the hinged members  162  may be held open by engaging a simple matching “V” shaped cam notch  201  (as previously described) appropriately positioned on the cylindrical receptacle&#39;s end face  167 . For retention in the closed position and in order to assure full closure to prevent loss of a lens during disinfection, it is preferable to have a mechanism that automatically urges each hinged member  162  into a position snuggly abutting the stem  142 , preferably with a small amount of sustained spring force such that looseness or gapping between stem  142  and hinged member  162  is prevented when closed. Each of the four cam followers  191  provided transverse to adjoining planar hinge pins  177  engages one of four appropriately placed closing cams provided on surface  181 , thereby keeping torque loads balanced and preventing undesirable sustained twisting loads against the hinge pin support ears  205 . 
     Since each hold closed cam is equipped with a hold closed ramp  203  having extra travel allowance to assure sustained closure force, the deepest points of the hold open and hold closed cams are positioned greater than 90 degrees relative to one another. As shown in  FIG. 26  (see also  FIG. 35 ), when the hinged members  162  are in the closed position, the cam followers  191  sit on the ramps  203  rather than in the notch  201  (i.e., in the lowest point of the cam). Although the hinge pin supporting ears  205  are preferably specifically designed for flexing in order to prevent an over-stressed condition leading to fracture, it is necessary to take care that the location and timing of the hold closed cam ramps  203  are such that only minimum sustained outward deflection is applied to the supporting ears  205  while in a closed position. 
     The hinged elements  162  on the planar stem  142  are preferably cylindrical in nature, each with slot interruptions  174  (see  FIGS. 19 ,  20 ,  26  and  28 ) located  180  degrees from one another in a plane perpendicular to the center line of the planar stem  142  to allow flushing and drainage and avoid trapping fluid while in an upright or inverted position. Additionally, as shown in  FIG. 23 , preferably a top surface of the stem  142  is shaped such that it provides internal vent ports  199 . 
     Preferably, the abutting mating faces of each cage  144  and its respective domed hinged members  162  are curved to match one another. An assembly of the planar central stem  142  with back-to-back lens cages  144  and mating curved domed hinged members  162  on either side results in a package that does not require as large a cup diameter to accommodate the internal components as would be required if the cages and domes were instead to be provided as having flat faces. Preferably, the case is configured such that use of curved, dome-carrying hinged members  162  allows a desirable lens cage inner base diameter of 0.75 inches to be employed without losing full lens immersion with 10 cc&#39;s of lens solution. 
     Making the dome  164  an integral, thin-walled and continuous element of the hinged member  162  allows a precise dome form to be quickly molded in a repeatable reliable manner without distortion or sink. Domes formed in this manner can be designed to optimize features necessary for preferential retention of lenses during placement and after disinfection or storage. 
     Other components of the contact lens case  140  include a sealing gasket  300  (shown in  FIGS. 31 and 32 ) with an integrally formed vent hole  308  and a plug  302  (shown in  FIGS. 33 and 34 ). The sealing gasket  300  is molded in place, fused within the cap  146 . As such, the gasket  300  does not exist as a separate component, separate from the cap  146 . Nevertheless, for clarity with regard to understanding the shape of the gasket  300 , the gasket  300  is shown alone in  FIGS. 31 and 32 ). While the gasket  300  is fused in place within the cap  146  when it is molded in place, the plug  302  is configured to engage the gasket  300  such that the three components, when assembled, provide an overall cap assembly (a cross-sectional view of which is shown in  FIG. 36 ). Preferably, the cap  146  has a flat top surface  305  (for resting on a tabletop or counter), a threaded surface  304  for threadably engaging the top  150  of the cup  152 , and a venting feature which will be described in more detail later hereinbelow. 
     In addition to the four apertures  163  on the cap  146 , the cap  146  includes a center hole  306  as shown in  FIGS. 29 and 30 . The gasket  300  includes four extending walls  309 , and the walls  309  are formed in the apertures  163  in the cap  146  when the gasket  300  is molded and fused in place to the inside surface  157  of the cap  146 . As these walls  309  are made out of elastomeric material, they compress and deflect out of the way of protrusions  161  (see  FIG. 23 ) to allow a snap fit engagement. The gasket  300  also has a center vent hole  308 , and openings  310  which are formed between the four extending walls  309 . As shown in  FIG. 34 , the plug  302  includes a stem  312  on its inner surface  314 , and this stem  312  inserts in the center hole  306  of the cap  146  and in the center vent hole  308  of the gasket  300 . Surrounding the stein  312  of the plug  302  is a circular wall  316 , and this circular wall  316  extends through the center hole  306  of the cap  146  and seats against a corresponding circular wall  318  which is provided on the top  320  of the gasket  300  as shown in  FIG. 31 . As shown in  FIGS. 33 ,  34  and  36 , a vent hole  322  is provided on the plug  302 , disposed in an area between the stein  312  and the circular wall  316 , to provide a venting feature. When assembled, the plug  302  seats in a recessed seat  334  which is provided on the cap  146 , and the pin  312  extends through the center vent hole  308  in the gasket  300 . 
     While specific embodiments of the invention are shown and described, it is envisioned that those skilled in the art may devise various modifications without departing from the spirit and scope of the foregoing description.