Container appliance with vent means

Abstract: An appliance (10) particularly for disinfecting contact lenses (38) disposed within a lens disinfecting solution which produces a gas during the disinfecting action, has a container body (12) with a lens holder (15) for supporting a pair of contact lenses (38) within the container (12) and a removable cap (14) with a vent means (42) which seals the container (12) to prevent contamination while permitting the venting of gases developed during the disinfecting action. The vent (42) consists of a post (46) positioned in a bore (44) such that the post (46) does not obstruct passage of gas from the inside of the container (12), and a resiliently deflectable apertured diaphragm (48) covering the bore (44). The diaphragm (48) is securely held in place over and around the post (46) whereby the post (46) protrudes through the aperture (54) in the diaphragm (48). The aperture (54) in the diaphragm (48) deflects away from the post (46) when the pressure within the container (12) exceeds a threshold pressure. Once the pressure within the container (12) is equalised with the ambience, the diaphragm (48) resiliently deflects to close the vent (42) thereby protecting the contents of the container (12) from contamination. Additionally, the apertured diaphragm (48) scrapes small particles of proteinaceous material and other matter off the post (46). Such matter is deposited on the post (46) by the exhausting gas and, if not for the scraping action, would build up on the post (46) rendering the vent (42) useless.

Description: This invention relates to an appliance for containing contact lenses during the cleansing and/or chemical sterilization or disinfecting of such lenses. In recent years extremely soft contact lenses have been fabricated from pliable plastic material which allowing extended wear without discomfort. These plastics are hydrophilic, and for that reason contact lenses manufactured from this material are susceptible to contamination by microorganisms. Additionally, as is common with all contact lenses, during use these soft contact lenses develop a natural build-up of proteinaceous material, however, this build-up is worsened by the extended wear of these lenses. Consequently, the user of these lenses must not only disinfect and/or sterilize the lenses, generally on a daily basis to remove the build up of microorganisms, but must also effect a cleaning to remove the build-up of proteinaceous material. Failure to properly clean the lenses may lead to congestion of the lens pores causing clouding of the lenses resulting in reduced visibility. Failure to disinfect or sterilize the lenses can lead to infections of the eye. Various disinfecting techniques are used which heat the lenses in a closed vessel in the presence of a saline solution, the heat being of such intensity and duration as to destroy the contaminating microorganism. More recently, however, sterilizing processes have been developed that do not require heating. These processes utilize a bactericide, for example hydrogen peroxide, which destroys the bacteria on the lenses. In this "cold sterilization" type process, the lenses are immersed in a weak solution of hydrogen peroxide generally a 3% solution, for several hours. While hydrogen peroxide is an effective bactericide, it is also capable of causing discomfort or injury to a wearer's eye. Therefore, in order to convert the hydrogen peroxide to a benign substance after sterilization is attained, a platinum catalyst is placed in contact with the solution to hasten the decomposition of the hydrogen peroxide, which decomposes to water and oxygen gas. A problem with this disinfecting process is that if a bactericide such as hydrogen peroxide is used, care must be taken to preclude the possibility of discomfort or injury to the wearer's eye by sufficiently neutralizing the disinfecting agent. Accordingly, the lenses are kept in the bactericide solution for sufficient length of time to destroy all of the bacteria, after which the lenses may be introduced into a rinsing solution to rinse out excess bactericide. Several hours is generally required to destroy essentially all of the bacteria and neutralize the hydrogen peroxide. A problem encountered with the foregoing process is that the liberated oxygen gas results in a build up of gas pressure within the sterilizing chamber and tends to cause leaking, spillage or both upon opening the chamber or when the cap of the unit is not sealed properly. In this regard, when the hydrogen peroxide is brought into contact with the platinum catalyst, the hydrogen peroxide solution tends to break down into water and liberated oxygen gas. The build up of liberated oxygen within the vessel creates pressure which must be vented. To overcome the problem of cleaning the lenses of the proteinaceous material, certain protein destroying enzymes also have been added to the sterilizing solution. As these enzymes work, the enzymes and the proteinaceous material result in small particles being held in suspension with the liberated oxygen gas that must be vented. Thus a vent means is needed which not only vents the liberated oxygen gas, but canal so accommodate the small particles carried by said gases. Further, this must be done in a manner which maintains the sterile integrity of the lens case; that is, prevents the entry of bacteria into the case from the external environment. In U.S. Patent No. 4,⊘11,941, there is shown and described a contact lens sterilizer for use with hydrogen peroxide and in which the oxygen gas pressure is relieved by displacing a rubber O-ring. Thus, the O-ring normally seals the unit, but also functions as a check valve. However, when the valve is "open", there is still the possibility of solution leaking therethrough. Moreover, the O-ring can lose resiliency over a period of time causing improper or ineffective valve operation. Further, the O-ring does not readily conform to irregularities in the seating structure and can become displaced leaving small openings through which bacteria may enter. Additionally, the small particles of the proteinaceous material and other matter removed from the contact lenses are carried by the exhaust gas out of the lens case. When gas is exhausted there is a tendency for proteinaceous material and other particles to be deposited and build up on the valve seating area, thereby creating irregularities which increase the likelihood of bacteria propogation. Not only does the O-ring ring valve not conform to irregularities due to the deposits on the valve, but it is also incapable of removing these deposits. Thus, over a period of time, the O-ring type vent valve is rendered useless since it does not have means to remove built up deposits. In U.S. Patent No. 4,637,919, an appliance is described for disinfecting contact lenses or the like which employs a hydrophobic membrane filter that continuously vents the build up of gas within the unit during the disinfecting process, while at the same time keeping the unit effectively sealed against leakage of disinfecting solution and entrance of bacteria into the sterilizing chamber. The membrane filter, while effective in venting oxygen gas and preventing the entry of bacteria, is susceptible to clogging when the sterilization solution includes enzymes for cleaning the lenses. The small particles carried by the liberated oxygen gas will be deposited upon the membrane during venting, and the membrane will soon become blocked and cease to function as a vent. The present invention, as will be detailed more fully hereinafter, overcomes the above described problem. More specifically, the present invention provides an improved vent means that permits oxygen gas to be vented, is not susceptible to clogging, and prevents the entry of bacteria from the exterior of a contact lens case. According to the present invention, there is provided an appliance for containing contact lenses during disinfection using a material which produces a gas during a reaction, said appliance comprising a container with an open end, a retaining means for supporting at least one contact lens within said container, a removable cap member for closing said open end, a bore in said cap member providing a passage from an inner surface of said cap to an outer surface of said cap, and vent means sealing said bore below a specified threshold pressure yet permitting escape of gases above a specified threshold pressure, characterised in that said vent means comprises a resiliently deflectable apertured diaphragm covering said bore and being securely held in place across said bore, a post member positioned in said bore, protruding through the diaphragm aperture and securely held in said aperture, whereby said post member does not obstruct passage of gas from the inside of said container through said bore, and means for restraining said post member within said aperture and in that the elasticity of said diaphragm is such that a predetermined pressure inside the container will result in deflection of the diaphragm to allow passage of gas from the container through said aperture. Said diaphragm is deflected by the build up of gas inside the container to permit said gas to be vented to the atmosphere. The diaphragm movement also tends to wipe the post and keep it clean and free of material. An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is an exploded partial elevational view of an appliance in accordance with the invention adapted as a case for disinfecting contact lenses; Figure 2 is an enlarged, partial sectional view of the assembled container cap and upper body portion of the container body shown in Figure 1; Figure 3 is an enlarged partial sectional view of the vent means of the invention illustrating passage of gas through the vent means in the container cap; and Figure 4 is a sectional view taken from the line 4-4 in Figure 2 and illustrating the position and structure of the post member in the vent means. It should be noted that dimensional relationships between mebers of the illustrated embodiment may vary and may have been varied to more clearly depict the features of the illustrated embodiment. Figure 1 shows a case 1⊘ which is used to contain a solution into which contact lenses or like objects are placed for the purpose of disinfecting and/or cleaning. To facilitate the cleaning, the case 1⊘ comprises a container 12 for receiving the solution in which the lenses are disposed, with a generally cylindrical body having an open end around which are formed threads 13 for receiving a removable cap member 14. The container 12 and removable cap member 14 are moulded from a suitable plastics material or the like. Mounted in the removable cap member 14 is a contact lens retaining means 15, which allows the contact lenses to be captively disposed within the solution in the container 12. The contact lens retaining means 15 is comprised of a disc or base member 16 and a lens supporting frame 18. As best shown in Figures 2 and 4, the surface of the disc 16 which faces the inside of the cap member 14, has an upstanding tongue 19 which fits into an aligning mortise 2⊘ formed in the cap 14. In an alternative embodiment of the removable cap member 14, the cap member 14, disc 16 and supporting frame 18 are integrally formed of plastics or other suitable material. The supporting frame 18, which is integrally moulded with the disc 16, projects downwardly into the container 12 when the cap 14 is mounted thereon. Intergrally moulded on the frame 18 are opposed, axially aligned trunions or pins 24. Opposed lens or object covers 26 are mounted on the pins 24. Each cover has an end piece 28 and a series of spokes 3⊘ radiating therefrom and being joined to their respective rims 32. A pair of flexible snap fingers 34 are formed on each cover 26 which allow the covers 26 to snap fit to the pins 24. When so mounted, each cover 26 is capable of independently hingedly moving about the pins 24 to captively hold objects to be disposed in the solution in the container 12. A special lens or object securing or mounting structure 36 has been integrally formed with the supporting frame 18 to complement the captive holding characteristics of the covers 26. This object securing structure 36 is comprised of outwardly facing convex button-like structures positioned on opposed sides of the supporting frame 18. These structures 36 are formed to receive the concave surface of contact lenses 38. The complementary operational design of the structure 36 receiving the concave portion of the lenses 38 and the concave structure of the covers 26, act to captively suspend the contact lenses 38 once disposed in the solution within the container 12. Additionally, the button-like structure forming the convex object securing structure 36 is suspended within the supporting frame 18 by a series of ribs (not shown) to permit the passage of fluid through the object securing structure 36. Similarly, an alternative embodiment may provide a structure for fixing or otherwise holding items rather than contact lenses 38 for insertion into a suitably sized container in a manner as previously described. As best shown in Figures 2 and 4, the cap member 14 comprises vent means 42 which permits the exhausting of gas developed within the lens case 1⊘. The vent means 42 comprises a bore 44, a post member 46, an apertured diaphragm 48 and diaphragm compressing means 5⊘. The post member 46 projects through the bore 44 and is secured in coaxial alignment with the bore 44 by tab means 51, which are formed integrally on one end of the post member 46 extending laterally from the post 46 and are secured to the inside facing surface of the disc 16 at the edge of the bore 44. The post member 46 is a solid cylindrical pin structure, with an outside diameter dimension being less than the inside diameter dimension of the bore 44 through which it protrudes. Additionally, the top end of the post member 46 is formed with a taper feature 52 to promote the directional biasing of the diaphragm 48. Thus constructed and positioned, the post member 46 provides a structural element of the vent means 42 without obstructing the flow of gas out of the lens case 1⊘. The diaphragm 48 which is circular-shaped and constructed of resiliently deflectable material having a substantially concentric aperture 54 therethrough, is stretched over the post member 46 resulting in the aperture 54 in the diaphragm 48 tightly sealing around the post member 46. The degree of tightness of the seal created by the diaphragm 48 being stretched over the post member 46 is controlled by such factors as the diameter of the post member 46, the diameter of the bore 44, the diameter of the aperture 54 and the characteristics of the material of the diaphragm 48. A supporting seat feature 56 is formed on the surface of the disc 16, which abuts the inside of the cap member 14, being generally concentric with the bore 44 through which the post member 46 protrudes. In the illustrated embodiment, the supporting seat feature 56 is generally circular, with a diameter approximately equal to the outside diameter of the diaphragm 48. The diaphragm 48 is secured in the seat feature 56 by the diaphragm compressing means 5⊘, which compress the diaphragm between this structure and the supporting seat feature 56. The diaphragm compressing means 5⊘ comprises two rings 57 integrally formed in the cap member 14 generally concentric with the bore 44. The rings 57 are generally formed with a triangular cross-section, whereby the apex 58 of each ring 57 presses into the diaphragm material 48 to securely hold the diaphragm in the supporting seat feature 56. As a result of stretching the aperture 54 of the resilient diaphragm material 48 over the post member 46, and securely holding the perimeter of the diaphragm 48 in the seat feature 56 by diaphragm compressing means 50, the aperture 54 portion of the diaphragm 48 is upwardly directionally biased. This directional biasing of the diaphragm 48 up around the post member 46 provides vent means 42 which permit exhausting of gas, but will not permit external gases and contaminants to enter the lens case 10. When the pressure within the container 12 of the illustrated embodiment exceeds a specified threshold pressure, for example above 5.17 x 10⁵ N/m² (Pascal) (75 psi), the diaphragm 48 resiliently deflects away from the post member 46 thereby opening the vent means 42 to allow passage of gas. The excessive pressure is relieved by the passage of gas from the inside of the lens case through the bore 44, past the post 46, through the resiliently deflected aperture 54 in the diaphragm 48 and out through the remainder of the bore 44 in the cap member 14. The flow path of the gas is illustrated by the arrows in Figure 3. When the pressure inside the lens case 10 is reduced below the pressure necessary to deflect the diaphragm 48, the diaphragm will resiliently deflect downwardly in an upwardly biased orientation, with the aperture 54 of the diaphragm 48 sealing around the post member 46. Repeated opening and closing of the vent means 42 provides the primary venting of gas throughout the disinfecting process, thereby allowing the release of gas while sealing the container against contamination. In an alternative embodiment (not shown), the diaphragm 48 is constructed of a resiliently deflectable gas-permeable hydrophobic material, such that below a specified threshold pressure required to deflect the diaphragm 48, gas is permitted to escape from the lens case 1⊘ through microscopic pores in the diaphragm 48. The diaphragm 48, while preventing bacteria and other contaminants from entering the lens case 1⊘, also prevents small particles of proteinaceous material and other matter from building up on the post member 46. During the disinfecting process, small particles of proteinaceous material and other matter are removed from the contact lenses and suspended in solution. When the gas builds up inside the lens case 1⊘ and is subsequently vented through the vent means 42, a portion of the small particles of proteinaceous material and other matter are liberated with the gas and tend to be deposited on the post member 46 while being transported through the exhaust bore 44. Since the aperture 54 of the resiliently deflectable diaphragm 48 is stretched over the post member 46, constricting forces are created by the stretched diaphragm aperture 54 on the post member 46. These constricting forces combine with the downward resilient deflection of the diaphragm 48 after the pressure within the chamber has been decreased below a threshold pressure, creating a highly effective scraping action. This scraping action is very important to the successful operation of the vent means 42 since without the scraping action, matter deposited on the post member 46 would build up and render the vent means 42 useless. The scraping acion can be further enhanced by die-cutting the leading edge 59 of aperture 54. An alternative embodiment (not shown) used to enhance the scraping action employs a sharp hard material implanted along the leading edge 59 of the diaphragm 48 of the aperture 54. In use, the contact lenses 38 are placed against the button-like structures 36 of the lens-supporting frame 18 and the covers 26 are then closed over the lenses 38 to secure the lenses 38 for disinfecting and cleansing. An appropriate disinfecting and cleaning solution is poured into the open end of the container 12 and, in addition, a catalyst 6⊘ may then be introduced to the solution if prescribed by the particular disinfecting procedure. The lens supporting structure 18, with the captive lenses 38 is disposed within the solution in the container 12, and then the container 12 is sealed by tightening the cap member 14 about the threads 13 on the open end of the container 12. The lenses 38 in the solution, as such, are left to the disinfecting process for a suitable length of time. During the disinfecting process gas is libertated from the solution which builds up pressure inside the lens case 1⊘. When the pressure exceeds a specified threshold pressure, the disphragm 48 resiliently deflects away from the post member 46 to open the vent means 42, thereby exhausting the excess pressurised gas. By venting the gas, the pressure within the lens case 1⊘ is relieved, and when this pressure is substantially equalised with the ambience, the diaphragm 48 resiliently deflects to seal around the post member 46. While sealing around the post member 46, the constrictive forces created by the resilient diaphragm aperture 54 and the leading edge 59 of the diaphragm aperture 54, scrape any material off the post member 46 which may have been deposited by the exhausting gas. Once the disinfecting process is complete, the lenses 38 are removed from the lens case 1⊘ and applied to the user's eyes in accordance with prescribed procedures.

Claims: An appliance (10) for containing contact lenses during disinfection using a material which produces a gas during a reaction, said appliance comprising a container (12) with an open end, a retaining means (15) for supporting at least one contact lens within said container (12), a removable cap member (14) for closing said open end, a bore (44) in said cap member (14) providing a passage from an inner surface of said cap (14) to an outer surface of said cap (14), and vent means (42) sealing said bore (44) below a specified threshold pressure yet permitting escape of gases above a specified threshold pressure, characterised in that said vent means (42) comprises a resiliently deflectable apertured diaphragm (48) covering said bore (44) and being securely held in place across said bore (44), a post member (46) positioned in said bore (44), protruding through the diaphragm aperture (54) and securely held in said aperture, whereby said post member (46) does not obstruct passage of gas from the inside of said container (12) through said bore (44), and means for restraining said post member within said aperture and in that the elasticity of said diaphragm (48) is such that a predetermined pressure inside the container (12) will result in deflection of the diaphragm (48) to allow passage of gas from the container (12) through said aperture. An appliance according to Claim 1, characterised in that said vent means (42) has a major axis aligned substantially with a major axis in an outer cap passage aligned substantially axially with said bore (44). An appliance according to Claim 1 or Claim 2, characterised in that said post member (46) is a solid cylindrical pin structure, with an outside diameter less than an inside diameter of said bore (44). An appliance according to Claim 3, characterised in that said means for restraining said post member (46) in said bore (44) includes tab means (51) for affixing said post member (46) to said cap member (14) to support said post member (14) in said bore (44). An appliance according to any one of Claims 1 to 4 characterised in that said resiliently deflectable apertured diaphragm (48) is mounted in a supporting seat feature (56), and said post member (46) is tapered at an end (52) over which said resiliently deflectable apertured diaphragm (48) is positioned, whereby directional biasing of said diaphragm (48) results when said diaphragm (48) has an aperture (54) with an inside diameter less than an outside diameter of said post member (46). An appliance according to Claim 5 characterised in that said cap member (14) further comprises diaphragm compressing means (50) formed integrally with said cap member (14) for compressing said diaphragm (48) between said diaphragm compressing means (50) and said seat feature (56) to secure said diaphragm (48) in said supporting seat feature (56). An appliance according to any one of Claims 1 to 6, characterised in that said diaphragm (48) is a resiliently deflectable gas permeable hydrophobic material for venting gas through micro pores in the material whereby below a threshold pressure required to deflect said diaphragm (48) gas is permitted to escape from said container (12) through said gas permeable material. An appliance according to any one of Claims 1 to 7, characterised in that said diaphragm aperture (54) has a leading edge (59) for scraping such particles or other matter which may be deposited on the surface of said post member (46) by exhausting gas from said post member (46).

Inventors: KANNER ROWLAND WILLIAM, WILLIAMS FRED EDWARD JR, KANNER, ROWLAND WILLIAM, WILLIAMS, FRED EDWARD, JR.
Applicants: RYDER INT CORP, RYDER INTERNATIONAL CORPORATION
Application year: 1989
Main classification: G02C13
IPC codes: A61L12, A45C11, G02C13