Abstract:
Additives that could interfere with the sealing of a cover onto a contact lens package are delivered separately from the bulk saline delivered into the lens package, thereby allowing more precise control of the additive delivery, reducing the incidence of additive in the seal area of the lens package, and improving the seal integrity.

Description:
[0001]    This application claims the benefit under 35 USC §119(e) of U.S. provisional application No. 60/984,129 filed Oct. 31, 2007, incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present invention relates generally to the packaging of ophthalmic contact lenses and, more specifically, to promoting good sealing of the contact lens package. 
         [0004]    2. Description of the Related Art 
         [0005]    Hydrophilic ophthalmic contact lenses are commonly packaged in individual primary containment packages, generally known as “blister packages” or “blister packs.” As shown in  FIG. 1 , a blister package  10  generally consists of a plastic (e.g., polypropylene) shell  12  having a concave or bowl-shaped depression or cavity  14  in which a lens (not shown) is disposed immersed in a sterile aqueous (saline) solution and sealed with a laminate foil cover  16 . A flat rim  18  surrounds the cavity  14 . (Shells  12  may include additional features to aid use and handling of the blister package  10 , but they are not shown for purposes of clarity.) As illustrated in  FIG. 2 , blister packages  10  are generally manufactured in strips comprising a number, such as five, of adjoining blister packages  10  that a user can easily separate by snapping them apart from one another. Such packaging keeps the lens in a hydrated and sterile state before being opened and worn by a user. Often, a lens is contained within a blister package for a significant amount of time while the lens is being shipped and held in storage before use. Therefore, it is important that the saline solution be hermetically sealed therein, to ensure that the solution cannot leak out and to prevent contaminants from entering the lens containment area. 
         [0006]    The stations of a conventional contact lens packaging line are illustrated generally in  FIG. 3 . Strips of the shells  12  (e.g., five shells) are carried in carrier trays (not shown), which are moved from one station to the next by a conveyor  19 . For purposes of clarity, however, the packaging process is described herein with respect to only a single lens and its package. At station  20 , a contact lens (not shown) is placed into a shell cavity  14  ( FIGS. 1-2 ). Shell  12  is then conveyed to a station  22  which fills cavity  14  with an amount of saline solution sufficient to ensure the lens is immersed. The saline solution contains, in addition to water and sodium chloride, one or more additives, such as buffers and lubricating agents. The filled shell  12  is then conveyed to a station  24  that uses ultrasonic vibration to remove any bubbles in the solution, as such bubbles could interfere with optical inspection of the lenses at the next station  26 . At station  26 , the lens is optically inspected by imaging the lens using a camera and image-processing equipment (not shown). The shell is then conveyed to a station  28  that places a foil cover  16  on it. Shell  12  then arrives at a station  30  that seals foil cover  16  to rim  18 . In one conventional method of sealing foil cover  16 , a heating element or heated seal plate presses foil cover  16  against rim  18  to heat-seal cover  16  to shell  12  to form the completed blister package  10 . 
         [0007]    Undesirable conditions during sealing can sometimes give rise to a poor, i.e., non-hermetic, seal between foil cover  16  and the shell  12 . For example, saline droplets can sometimes undesirably splash upon rim  18  during the step of the packaging process (e.g., station  22 ) at which cavity  14  is filled with saline solution. When shell  12  is subsequently sealed with foil cover  16  (e.g., at station  30 ), such droplets can create wrinkles in foil cover  16  and/or otherwise prevent foil cover  16  from properly adhering to shell  12 , giving rise to undesired channels or pathways between foil cover  16  and cavity  14  that can permit the saline solution to leak out or contaminants to infiltrate cavity  14  and contaminate the lens. Saline solutions having certain additives included therein have been found to interfere with proper sealing to a significantly greater extent than would pure saline without those additives, when present in the sealing area. 
         [0008]    Accordingly, needs exist for improvements to contact lens packaging systems that promote good, i.e., hermetic, seals between the cover and plastic shell of a blister package. The present invention is directed to these needs and others in the manner described below. 
       SUMMARY 
       [0009]    The present invention relates to a system and method for delivering or dosing at least one additive, such as a buffer or lubricant, into a contact lens package separately from the bulk dispensing of saline without said additive(s) into the lens package. For example, the saline is delivered at a dispensing station into the lens package, and the one or more additives are separately delivered at a dosing station. The quantity of additive dosed into the lens package is substantially less than the quantity of saline dispensed into the lens package, thereby permitting more precise and controlled dosing of the additive, and/or permitting dosing of the additive at a substantially lower flow-rate than the saline. After the package has been filled in this manner, it can be sealed with a cover in any conventional manner. The separate, controlled dosing of additive greatly reduces the likelihood of splashing the additive, or solution containing the additive, onto the rim of the lens package where it could interfere with proper sealing of the cover. 
         [0010]    In an exemplary embodiment of the invention, a contact lens package is delivered to a dispensing station where saline solution not containing a specified additive is introduced into the lens package. The contact lens package is then delivered to a dosing station where at least one additive including the specified additive is introduced into the saline previously delivered into the lens package. A conventional conveyor system or similar device can be used to move the contact lens packages from station to station in essentially the same manner in which such a system moves such packages in a conventional contact lens packaging line. In alternate embodiments, the additive is dosed into the lens package prior to dispensing the saline into the lens package; and in still other embodiments, the additive and the saline are simultaneously delivered into the lens package via separate delivery mechanisms. 
         [0011]    In another aspect, the invention is a method of packaging a contact lens, the method including depositing a contact lens into a container, the container defining a lens-receiving cavity and a sealing surface surrounding the lens-receiving cavity. The method further includes dispensing saline solution into the lens-receiving cavity at a first delivery rate, and dosing at least one additive into the lens-receiving cavity separately from the saline solution at a second delivery rate substantially less than the first delivery rate. Delivery of the at least one additive is controlled to prevent depositing additive on the sealing surface surrounding the lens-receiving cavity. The method further includes applying a cover over the lens-receiving cavity in sealing engagement with the sealing surface. 
         [0012]    In still another aspect, the invention is a method for dosing saline solution with an additive during contact lens packaging. The method includes introducing saline solution not containing a specified additive into a contact lens package, and separately introducing the specified additive into the contact lens package to combine the specified additive with the saline solution in the contact lens package. 
         [0013]    In yet another aspect, the invention is system for packaging contact lenses, the system including a conveyor for moving contact lens packages along a contact lens packaging line, a lens delivery station for placement of contact lenses in the contact lens packages, and a saline dispensing station for delivering saline solution not having a specified additive therein into the contact lens packages. The system also includes an additive dosing station for delivering the specified additive into the contact lens packages separately from the saline solution, without depositing the specified additive onto a seal area of the contact lens packages. The system also includes a sealing station for hermetically sealing a cover onto the seal area of each of the contact lens packages. 
         [0014]    In another aspect, the invention is a contact lens product including a primary lens containment package incorporating a shell defining a lens-receiving cavity, and a cover for placement over the lens-receiving cavity. The product further includes a contact lens removably disposed within the lens-receiving cavity, a quantity of saline solution disposed within the lens-receiving cavity, and a quantity of an additive dosed into the lens-receiving cavity separately from the saline solution. The cover is hermetically sealed to the shell without interruption by any of the additive being deposited between the shell and the cover. 
         [0015]    These and other aspects, features and advantages of the invention will be understood with reference to the drawing figures and detailed description herein, and will be realized by means of the various elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following brief description of the drawings and detailed description of embodiments of the invention are exemplary and explanatory only, and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a side elevation view of a blister pack, in accordance with known art, showing the foil cover over the rim of the shell. 
           [0017]      FIG. 2  is a top view of a strip of blister pack shells, in accordance with known art. 
           [0018]      FIG. 3  illustrates a plurality of stations of a contact lens packaging line, in accordance with known art. 
           [0019]      FIG. 4  illustrates a plurality of stations of a contact lens packaging line, in accordance with an exemplary embodiment of the present invention. 
           [0020]      FIG. 5  illustrates in further detail the saline dispensing station of the contact lens packaging line of  FIG. 4 . 
           [0021]      FIG. 6  illustrates in further detail the additive dosing station of the contact lens packaging line of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0022]    The present invention may be understood more readily by reference to the following detailed description of the invention taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed invention. 
         [0023]    Also, as used in this specification (“herein”) including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. With regard to specific combinations of elements described herein, such elements can alternatively be combined in any other suitable manner with each other or with still other elements, and some elements can be omitted, or portions of the elements combined together with portions of other elements to form elements that differ from those specifically described. With regard to specific method steps described herein, unless otherwise stated, the steps can alternatively be performed in sequences other than those specifically described, and some steps can be omitted, or portions of the steps combined together to form steps that differ from those specifically described. Persons skilled in the art to which the invention relates will appreciate that the invention encompasses such alternatives. 
         [0024]    The stations of a contact lens packaging line in accordance with an exemplary embodiment of the present invention are illustrated generally in  FIG. 4 . A conveyor system  32  moves the contact lens shells  12  ( FIG. 1 ) in carrier trays (not shown for purposes of clarity) from station to station. Conveyor system  32  can include various types of devices and is not limited to a single conveyor belt or other single device. The trays can be of conventional design and carry strips ( FIG. 2 ) of shells  12  in the conventional manner. The packaging line can operate in a continuous or indexed manner, with successive shells  12  carried by conveyor system  32  arriving at the stations and successively undergoing the process steps or operations described herein. For purposes of clarity, however, the process is described herein with respect to only a single shell  12 . 
         [0025]    Conveyor system  32  delivers a shell  12  to a lens placement station  34 . Station  34  places a contact lens (not shown) into the cavity of shell  12  in any conventional manner. Conveyor system  32  then delivers the shell  12  to a saline dispensing station  36 . In alternate embodiments, the saline is dispensed into the shell prior to lens transfer. Station  36 , shown in further detail in  FIG. 5 , fills the cavity of shell  12  with a metered amount of saline solution  38 . Saline solution  38  preferably has no additives, i.e., it consists essentially of an aqueous sodium chloride solution; or includes additives that do not significantly interfere with sealing of the cover, but does not include one or more specified additives that may interfere with sealing and therefore are to be separately dosed. Filling is controlled by a suitable metering controller  40  that can comprise any suitable combination and arrangement pumps, valves, pipette droppers, or similar devices as known in the art. Controller  40  controls the flow or movement of saline solution  38  from a saline supply tank or reservoir  42  in which it is stored, to the cavity of shell  12 , as shown in  FIG. 5 . 
         [0026]    Conveyor system  32  subsequently delivers the shell  12  to an additive filling (or “dosing”) station  44 . Station  44 , shown in further detail in  FIG. 6 , doses the cavity of shell  12  with a metered amount of one or more additives  46 . The additive is typically provided in liquid form, but alternatively may be in solid, powdered, gel or other form. Dosing is controlled by a suitable metering controller  48  that can comprise any suitable combination and arrangement of pumps, valves, pipette droppers, dosing needles, or similar devices as known in the art. Controller  48  controls the flow or movement of additives  46  from an additive supply tank or reservoir  50  in which it is stored, to the cavity of shell  12 , as shown in  FIG. 6 . As the amount of additives  46  introduced into the cavity of shell  12  is small relative to the amount of bulk saline dispensed into the shell (in some instances, for example, only a droplet or two of additive per lens package, typically less than about 50%, less than about 35%, less than about 25%, less than about 10%, less than about 5%, or less than about 1% the volume of the bulk saline), the introduction is more precisely controllable and therefore less likely to result in additive splashing on the rim of shell  12 . In embodiments of the invention providing equal cycle time for the additive dosing operation(s) and the saline dispensing operation, the delivery rate of additive(s) is generally reduced in proportion to the additive-to-saline ratio. As a result, separate dosing of the additive(s) allows delivery at a lower and more controlled delivery flow-rate, without slowing down the overall packaging process. In alternate embodiments of the invention, two or more dosing stations are included for separate delivery of different additives, and/or a single dosing station delivers one or more different additives either separately or in combination with one another. Also, the present invention includes systems and methods wherein one or more dosing station(s) deliver additive(s) to a lens package before, after, and/or simultaneously with the separate delivery of bulk saline not including said additive(s) to the lens package. The saline and/or the additive(s) can be delivered into the lens package before, after, or along with the contact lens. 
         [0027]    The conveyor system  32  optionally delivers the lens packaging shell  12  through further processing stations, as shown in broken lines in  FIG. 4 . As these stations are conventional and thus well-understood in the art, they are not described in detail herein. The processing stations optionally include a bubble-removal station  52  that uses ultrasonic vibration to remove any bubbles in the solution, as such bubbles could interfere with optical inspection of the lenses and/or the packages. The lens and/or the package is optionally inspected at an in-package inspection station  54  by imaging the lens using a camera and image-processing equipment (not shown). These and/or other optional additional processing stations may be positioned upstream and/or downstream from the dosing station  44 . 
         [0028]    Shell  12  is then conveyed to a cover placement station  56  that places foil laminate cover  16  ( FIG. 1 ) on it. The covered shell  12  then arrives at a closure and sealing station  58  that seals the foil laminate cover  16  to the rim of shell  12  using a heated seal plate or other suitable means as known in the art. Improved seal integrity is provided as a result of the reduced likelihood that seal-interfering additives were present in the seal area on the rim of the shell  12  during the closure and sealing step of the packaging process. While the invention has been described with reference to preferred and example embodiments, it will be understood by those skilled in the art that a variety of modifications, additions and deletions are within the scope of the invention, as defined by the following claims. With regard to the claims, no claim is intended to invoke the sixth paragraph of 35 U.S.C. Section 112 unless it includes the term “means for” followed by a participle.