Abstract:
An eye drop dispensing device includes a trough member with a space to receive a cartridge housing enclosing a collapsible bag containing an ophthalmic liquid and comprising a spring finger applying pressure to the bag. The bag includes a wall pierced by a needle coupling the liquid to pump means through a one-way valve. The pump means includes a plunger biased to a resting position establishing a dosage chamber. Actuator means moves the plunger to enlarge the dosage chamber, causing a drop in pressure which draws a predetermined quantity of the liquid through the one-way valve into the dosage chamber. The actuator means then releases the plunger so that it moves to compress the dosage chamber to pump the liquid in the dosage chamber through a second one-way valve to spray the liquid through pinholes formed in a nozzle angled to direct the liquid as eye drops to the user&#39;s eye. Another embodiment receives a cartridge housing enclosing three collapsible bags containing three different prescription ophthalmic drug solutions. The embodiment includes three shuttle pumps which are controlled by a common control member to dispense the solutions simultaneously into the patient&#39;s eye.

Description:
[0001]    This is a continuation-in-part of application Ser. No. 09/776,782, filed Feb. 6, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    This invention relates to an eye drop dispensing system, and, more particularly, to a portable, compact, low-cost eye drop dispensing system using a simple spring-powered pump to spray a predetermined quantity of an ophthalmic liquid into a user&#39;s eye.  
           [0004]    2. Description of the Prior Art  
           [0005]    U.S. Pat. No. 5,607,410, assigned to the same assignee as the present application, shows portable eye wash systems intended for use in an emergency. These systems include a fluid reservoir having a flexible squeeze container mounted on a housing and a trough pivoted at one end to the housing. An eye piece at the other end of the trough is engaged with the user&#39;s face adjacent his eye. For enabling the user to view his eye, a mirror is mounted on the housing. A fluid line extends from the housing along the trough to a spray outlet on the trough positioned to spray the user&#39;s eye.  
           [0006]    Another portable eye wash system is shown in copending application Ser. No. 09/472,248, filed Dec. 27, 1999, which application is assigned to the same assignee as the present application. In order to facilitate single drop dosing in the system of Ser. No. 09/472,2481, two embodiments of metering spray nozzles are disclosed.  
           [0007]    Py U.S. Pat. No. 5,163,929 shows an ocular vial for applying a 20 microliter drop of medicament into the user&#39;s eye. A supply cavity feeds the liquid to a drop cavity which is then closed by a piston. When the piston is depressed, the drop is applied through an orifice. This device is a complex eye dropper which does not spray the liquid into the user&#39;s eye and includes no means for positioning a spray outlet relative to the user&#39;s eye.  
           [0008]    Py U.S. Pat. No. 5,267,986 also shows a dispenser including a drop cavity which holds a predetermined volume of fluid to be emitted in the form of a drop. A spring causes expansion of the dispenser to emit a drop through a nozzle. A projecting finger is engaged with the user&#39;s eyelid.  
           [0009]    Py U.S. Pat. No. 4,946,452 also uses an eyepiece for properly positioning a medicament dispenser. An outer housing is slidably engaged over an inner housing to force the closed end of the vial towards the nozzle and displace a predetermined volume of medicament through a nozzle.  
           [0010]    Landsberger et al U.S. Pat. No. 4,641,384 show an eyewash system including a pump operated by batteries.  
           [0011]    Vo U.S. Pat. No. 5,171,306 provides an eye drop delivery system which ejects eye drops through nozzles mounted on the frame of a pair of glasses. A fluid reservoir and fluid driving means are located in a separate case.  
           [0012]    Akiyama et al U.S. Pat. No. 4,215,689 show injecting apparatus held against a living body and including a reservoir in the form of a bag containing a medical liquid. A needle penetrates a thickened portion of the bag to permit flow of the liquid through a conduit. The liquid is pumped by pump means driven by movement of the living body.  
           [0013]    Rohrbough U.S. Pat. No. 5,324,258 shows a reservoir module for a drug delivery system. A medicament vial is closed at one end by a penetrable stopper. A hollow needle pierces the stopper and provides a flow path to a peristaltic pump.  
           [0014]    Moss et al U.S. Pat. No. 5,336,190 provide a cassette assembly for an ambulatory medical infusion pump with a reservoir bag having a tube squeezable by a pump mechanism.  
           [0015]    Johnson U.S. Pat. No. 5,658,252 discloses a peristaltic drug pump.  
           [0016]    As will be apparent from a review of the prior art, the pump-assisted delivery of an accurate dose of an ophthalmic rinse or medicament solution or, more generally, the pump-assisted delivery of medication to a body, have required the use of electric power or, in one case, power derived from movement of the body. It also appears from the prior act that there is a need for a cartridge enclosing a collapsible bag or container for the ophthalmic liquid which is convenient to insert and replace.  
         SUMMARY OF THE INVENTION  
         [0017]    It is an object of this invention to provide an improved portable, low cost eye drop dispensing system with pump-assisted delivery of a predetermined quantity of an ophthalmic liquid as an accurate dose to an eye.  
           [0018]    It is an additional object to provide an eye drop dispensing system with a readily replaceable cartridge enclosing a collapsible bag or chamber for the ophthalmic liquid. The cartridge comprises a cartridge housing having a spring finger formed in its top wall applying positive pressure to the collapsible chamber. The collapsible chamber has a piercable entry wall positioned to be pierced by a hollow needle extending through an opening in the cartridge housing for feeding the liquid to pump means for spraying the liquid into a user&#39;s eye.  
           [0019]    It is a further object to provide a first embodiment of an eye drop dispensing system with improved pump means for delivering eye drops through a spray nozzle to a user&#39;s eye. The pump means comprises a plunger, having a piston head movable in a cylindrical bore. The plunger is spring biased to move the piston head to a resting position in the bore, the piston head forming a wall of a dosage chamber. Actuator means is engaged by the user to engage and move the plunger in a direction expanding the dosage chamber and thereby creating negative pressure in the dosage chamber. This causes the ophthalmic liquid to flow from a liquid reservoir through a one-way valve into the dosage chamber. After the actuator means has moved the plunger a predetermined distance, an arm on the actuator means engages a sloped surface or ramp to move the actuator means out of engagement with the plunger allowing the plunger to be driven by the biasing spring to move the piston head in a direction to compress the dosage chamber and pump a predetermining dose of the ophthalmic liquid out of the dosage chamber through a second one-way valve and through a spray nozzle into the user&#39;s eye.  
           [0020]    The spray nozzle comprises a nozzle chamber with an end wall having a plurality of pin holes through which the liquid is sprayed. The nozzle chamber is angled to direct the liquid to the user&#39;s eye.  
           [0021]    The eye drop dispensing system includes a trough member with an eye piece formed on a wall at the front end of the trough member. A spray space is formed in the trough member behind the wall, and a pump housing is positioned in the trough member behind the spray space. The pump means is located within the pump housing. A cartridge receiving space is provided in the trough member between the rear end of the trough member and the pump housing. The cartridge housing is removably received in the cartridge receiving space from the rear end of the trough member. The spray nozzle is mounted at the front end of the pump housing to spray the liquid through the spray space into a user&#39;s eye positioned above the eye piece.  
           [0022]    The eye drop dispensing system of the first embodiment teaches dispensing a single ophthalmic liquid or medicament solution into the user&#39;s eye. However, it is necessary for the treatment of some eye conditions, such as glaucoma, dry eyes or infections, to dispense a plurality of prescription drug solutions into the user&#39;s eye. For example, in the treatment of glaucoma it is desirable to simultaneously dispense three prescription medicament solutions, such as scopolamine, timolol and prostaglandin agonists to the patient&#39;s eye. It is possible to do so using a second embodiment of an eye drop dispensing system of the invention.  
           [0023]    In this embodiment, the cartridge receiving space is adapted to receive three readily replaceable cartridges, each comprising a collapsible container for containing one of three ophthalmic liquids or medicament solutions. The cartridge housing has a spring finger formed in its top wall applying positive pressure on the collapsible chambers. Each of the collapsible chambers has a piercable entry wall positioned to be pierced by a respective hollow needle extending through an opening in the cartridge housing for feeding liquids from the respective collapsible chamber to individual pump means for spraying the liquids into a user&#39;s eye.  
           [0024]    Each of the pump means may comprise a shuttle pump having an actuator arm engaged with a plunger shaft reciprocable within an inner shuttle chamber, which in turn is reciprocable within an outer shuttle chamber. A coil spring is positioned between an end of the outer shuttle chamber and the actuator arm to bias the actuator arm to an outward position.  
           [0025]    Each hollow needle extends from a respective outer shuttle chamber to which it feeds the ophthalmic liquid or medicament from a respective collapsible chamber. As an actuator arm is biased to its outward position, the inner shuttle chamber is pulled by the plunger to a position in which an opening into the inner shuttle chamber is aligned with the hollow needle, and since the outward movement of the plunger causes a drop in the pressure within the inner shuttle chamber, the liquid is drawn from the hollow needle to fill the inner shuttle chamber with an appropriate dose of the liquid. When the actuator arm is then depressed, the piston moves toward the far end of the inner shuttle chamber to pressurize the liquid within the inner shuttle chamber and force the inner shuttle chamber to move within the outer shuttle chamber until an outlet opening from the inner shuttle chamber aligns with an outlet conduit leading to the nozzle forcing the liquid to be sprayed from the nozzle into the user&#39;s eye. When the actuator arm is released, it is again biased to the outward position to again draw the liquid into the inner shuttle chamber.  
           [0026]    A single control member projects from the housing and is connected to a control rod from which the respective actuator arms extend. A spring biases the control member outwardly of the housing allowing each of the actuator arms to be biased to their outward positions. When the control member is depressed, each of the actuator arms is depressed as well, forcing the liquids from the inner shuttle chamber of each pump through respective conduits to the nozzle and into the user&#39;s eye.  
           [0027]    Other objects, features and advantages of the invention will become apparent from the following detailed description and the drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    [0028]FIG. 1 is a perspective view of a first embodiment of an eye drop dispensing system of the invention with the cover pivoted to an open position;  
         [0029]    [0029]FIG. 2 is an exploded view corresponding to the perspective view of FIG. 1;  
         [0030]    [0030]FIG. 3 is a side view, partially in cross section, of the system of the invention;  
         [0031]    [0031]FIG. 4 is a top view showing the trough member of the system;  
         [0032]    [0032]FIG. 5 is a partial perspective view, with parts broken away, showing a cartridge housing in position to be inserted into the trough member of the system;  
         [0033]    [0033]FIG. 6A is a partial cross section view along line  6 - 6  of FIG. 8 of the pump means of the system in its resting position;  
         [0034]    [0034]FIG. 6B is a cross section view corresponding to FIG. 6A of the pump means after a user has partially depressed the actuator button with the plunger raised;  
         [0035]    [0035]FIG. 6C is a cross section view corresponding to FIG. 6A of the pump means with the plunger moving back into the dosage chamber and the actuator button fully depressed with the central lifting arm portion of the actuator moved out of engagement with the head of the plunger;  
         [0036]    [0036]FIG. 7A is a partial perspective view showing the central engagement arm of the actuator means engaged with the head of the plunger;  
         [0037]    [0037]FIG. 7B is a partial perspective view showing the plunger in its raised position with the side engagement arms of the actuator engaged with sloping surfaces so that the actuator is moved laterally with the central lifting arm portion still engaged with the head of the plunger;  
         [0038]    [0038]FIG. 7C is a partial perspective view showing the side engagement arms of the actuator engaged with the sloping surfaces so that the actuator is moved laterally with the central lifting arm portion moved free of the head of the plunger and with the plunger moving back into the dosage chamber;  
         [0039]    [0039]FIG. 8 is a partial cross section view along line  8 - 8  of FIG. 6A;  
         [0040]    [0040]FIG. 9 is a partial cross section view showing the seal engaged with the spray nozzle;  
         [0041]    [0041]FIG. 10 is a perspective view of a second embodiment of an eye drop dispensing system of the invention with the cover pivoted to an open position;  
         [0042]    [0042]FIG. 11 is an exploded view of the embodiment of FIG. 10;  
         [0043]    [0043]FIG. 12 is a partial exploded view corresponding to the view of FIG. 11, but with the cartridges in position within the housing;  
         [0044]    [0044]FIG. 13 is a schematic section view of the pump means of the embodiment of FIG. 10 with the plunger retracted;  
         [0045]    [0045]FIG. 14 is a schematic section view corresponding to the view of FIG. 13, but with the plunger partially depressed;  
         [0046]    [0046]FIG. 15 is a schematic section view corresponding to the view of FIG. 13, but with the plunger fully depressed;  
         [0047]    [0047]FIG. 16 is a schematic section view showing the common control member in its retracted position; and  
         [0048]    [0048]FIG. 17 is a schematic section view corresponding to FIG. 16, but with the control member depressed. 
     
    
     DETAILED DESCRIPTION  
       [0049]    As shown in FIGS.  1 - 5 , a first embodiment of an eye drop dispensing system  10  of the invention includes a trough  12  having a front end wall  14  on which an arcuate eye piece  16  is formed. As is known in the art, eye piece  16  will be positioned on a user&#39;s face just below an eye to be treated.  
         [0050]    A spray space  18  is positioned in trough  12  behind wall  14 , and a spray nozzle  20  is located in spray space  18 . As will be explained in more detail below, spray nozzle  20  is mounted to receive ophthalmic liquid to be sprayed from pump means located within a pump housing  22  located behind spray space  18 .  
         [0051]    A cartridge receiving space  24  (see FIGS. 2 and 3) is positioned behind pump housing  22 . In order to receive a cartridge housing  26 , the bottom wall  28  of cartridge receiving space  24  has a pair of guide grooves  30  and  31  (see FIG. 5) and side walls  32  and  34  (see FIG. 2) each of which has a guide groove  36  (only one of which is seen).  
         [0052]    Cartridge housing  26  comprises a top wall  38  (see FIG. 3) from which a spring finger  40  is cut, having a base portion  42  (see FIG. 1) connected to top wall  38  at the front end of housing  26 . As best seen in FIG. 3, spring finger  40  applies positive pressure to a collapsible bag or chamber  42  formed of a resilient material, such as silicone rubber, and containing the ophthalmic liquid  44 .  
         [0053]    In order to provide access to liquid  44  within chamber  42 , the front end of collapsible bag  42  is provided with a piercable entry wall  46 , closing a neck portion  47  (see FIG. 2) of collapsible bag  42 . As seen in FIG. 5, a hollow needle  48  extends through an opening  50  at the front end of housing  26 . Neck portion  47  of bag  42  is seated in opening  50 .  
         [0054]    Cartridge housing  26  has parallel rails  52  and  53  (see FIG. 2) extending downwardly from its bottom wall and fitting in guide grooves  30  and  31 , respectively. Side rails  54  are provided on the outer surfaces of side walls  56  and  57 . These are received in respective side grooves  36 . The rear ends of side rails  54  are formed as resilient catches  58  to secure cartridge housing  26  in cartridge receiving space  24  by cooperating with posts  59  and notches  62  and  63  formed at the rear ends of side grooves  36 .  
         [0055]    Cartridge housing  26  is slid into cartridge receiving space  24  through an opening  60  at the rear end of trough  12  with rails  52 ,  53  and  54  engaged in guide grooves  30 ,  31  and  36 . When cartridge housing  26  is fully inserted, hollow needle  48  pierces piercable entry wall  46 . In this way, ophthalmic liquid  44  is made available for pump means within pump housing  22 . When cartridge housing  26  is fully inserted, resilient catches  58  engage notches  62  and  63  at the ends of grooves  36  (see FIG. 5) to retain cartridge housing  26  in cartridge receiving space  24 .  
         [0056]    As best seen in FIGS. 2 and 3, pump means  64  is received in pump housing  22  through an opening  66  through the bottom wall  28  of trough  12 . Turning to FIG. 6A, which shows pump means  64  in its resting position, pump means  64  comprises a dosage chamber  68  at the bottom of a cylindrical bore  70 . A plunger  72  is movable within bore  70  and is biased towards the bottom end (as seen in FIG. 6A) by a spring  74  which is engaged between the top wall  76  of bore  70  and a flange or lip  78  at the bottom end of plunger  72 . Flange  78  is so configured and dimensioned that it is movable up and down in bore  70 , serving as a piston head  79  forming the top wall of dosage chamber  68 . Plunger  72  has a rod extension  80  of smaller diameter below piston head  79 . An O-ring cushion  82  embraces the lower end of rod  80 , resting, in part, on a flange or lip  81  at the bottom end of rod  80 . When plunger is in its resting position, flange  81  is received in a bore  87  in end wall  86 , while O-ring  82  rests, in part, on the portion of end wall  86  surrounding bore  87 . An O-ring  84  seals chamber  68  where it terminates at end wall  86 .  
         [0057]    Hollow needle  48  is mounted at one end in a bore  88  in a ring  90 . Bore  88  leads to a valve chamber  92  of a one-way valve  94 , which comprises a ball  96  which is biased by a spring  98  to a closed position in which ball  96  is pressed against an O-ring  100 . One way valve  94 , when open, permits liquid to flow into dosage chamber  68  through inlet passageway  102 .  
         [0058]    A second one-way valve  104  is positioned in outlet passageway  106  extending from dosage chamber  68  through outlet member  107  and comprises a valve ball  108  which is biased by a spring  110  to a closed position pressing against O-ring  112 . Beyond valve  104 , outlet passageway  106  extends through a thick-walled portion  114  of member  107  and then through a thin walled outlet portion  116 . A tapered connector ring  117  is formed on the outer side of outlet portion  116 . As seen in FIGS. 6A, 6B and  6 C, nozzle member  20  has an inlet portion  118  with an inlet passageway  120 . Nozzle member  20  is formed of a plastic material, such as ABS or polypropelene, which permits inlet portion  118  to be slipped over the end of outlet portion  116  and snap over tapered ring  117  to secure nozzle  118  on outlet portion  116 .  
         [0059]    Pump means  64  also includes acuator means  122 . An actuator button  124  projects from one side of pump means  64  (see FIGS. 1, 2,  3 ,  4 ,  5 ,  6 A,  6 B,  6 C and  8 ) and is mounted on an end of actuator rod  126  and is biased outwardly of pump means  64  by a spring  128 .  
         [0060]    As seen in FIG. 8, rod  126  extends into a bore  130  and is surrounded by spring  128  within bore  130 . Rod  126  is widened to form a shoulder  132  against which one end of spring  128  presses, the other end pressing against the inside surface of button  124 . An extension  134  of actuator rod  126  extends through a rectangular extension  136  of bore  130 . As seen in FIGS. 7A, 7B, and  7 C, extension  134  terminates in an actuator arm member  138  which has lateral arm portions  140  and  141  and a lifting arm portion  142 .  
         [0061]    As best seen in FIGS. 6A, 6B,  6 C,  7 A,  7 B,  7 C, and  8 , screw members  144  and  145  are positioned near arm member  138  so that respective sloped surfaces or ramps  146  and  147  will become engaged with respective arm portions  140  and  141  as arm member  138  is raised, as will be presently explained.  
         [0062]    It will be noted that the upper end (as seen in FIGS. 6A, 6B, and  6 C) or plunger  72  is provided with an enlarged head  150  forming a lip  152  which, as will be explained below, will be engaged by lifting arm portion  142  to lift plunger  72 .  
         [0063]    Spray nozzle  20 , as mentioned above, includes an inlet portion  118  which slips over outlet portion  116  of pump means  64 . Inlet portion  118  is connected to a tubular angled portion  154 , which is tipped an angle of 45 degrees to inlet portion  118 , and which, in turn, is connected to a hollow cylindrical nozzle chamber member  156 . An end wall  158  closes hollow chamber member  156 . In order to enable spraying of the ophthalmic liquid, a plurality of pinholes  160  are provided through end wall  158 . When spray nozzle  20  is mounted on outlet member  107 , the angled portion  154  will so position end wall  158  that the liquid will spray through pinholes  160  in a direction to enter a user&#39;s eye when eye piece  16  is positioned just beneath the user&#39;s eye.  
         [0064]    The device includes a cover  162  which includes a pair of pivot holes  164  and  165  adjacent one end. These pivot holes are mounted on pivot pins  166  and  167  which project from respective side walls  34  and  32  of trough  12  adjacent the rear end thereof. Cover  162  has a pair of side walls  168  and  169  which, when cover  162  is in its closed position, fit just outside the outer sides of side walls  34  and  32 , respectively, of trough  12 . The front end of cover  162  (the end opposite the pivoted end) has an end wall  170  having an arcuate edge  172  which is complementary to and is received on the arcuate surface of eye piece  16 .  
         [0065]    As is known in the art, a mirror  174  is glued to the inner side  176  of a top wall  178  of cover  162 . Mirror  174  is so placed that a user who has placed eye piece  16  beneath his or her eye will be assisted in properly positioning the device by observing his or her eye in mirror  174 .  
         [0066]    A seal  180  is formed on inner surface  176  of top wall  178  and has a sealing surface  182  (see FIG. 3) which is so positioned and angled that, when cover  162  is in its closed position, sealing surface  182  abuts and seals end wall  158  and pinholes  160  of nozzle  20 . In order to enhance the sealing function of seal  180 , it is provided with a peripheral lip  184  which, when cover  162  is in its closed position, snugly embraces nozzle end portion  156 .  
         [0067]    When eye drop dispensing system  10  is used, the user must first insert a cartridge housing  26  in cartridge receiving space  24 . This is accomplished by inserting housing  26  into space  24  through rear opening  60  of trough  12 . With the end wall  51  of cartridge housing  26  through which opening  50  extends being inserted into opening  60  first, bottom rails  52  and  53  are engaged with guide grooves  30  and  31 , respectively, in bottom wall  28  of trough  12  and side rails  54  and  56  are engaged with side grooves  36  formed in side walls  32  and  34  of trough  12 . Cartridge housing is then slid forward until piercable end wall  46  of collapsible bag  42  is pierced by needle  48  extending rearwardly from pump housing  22 . This couples collapsible bag with valve chamber  92  of one-way valve  94 . As mentioned above, spring finger  40  of cartridge housing  26  applies pressure upon collapsible bag  42 . However, this pressure is not sufficient to permit the fluid  44  in bag  42  to overcome the bias provided in one-way valve  94  by spring  98 . Rather, the pressure on bag  42  primes one way valve  94  to make it more responsive to a drop in pressure in dosage chamber  68  upon movement of plunger  72  as will presently be described.  
         [0068]    The normal resting position of plunger  72  is shown in FIG. 6A. Bias spring  74  is engaged with flange  78  at the lower end of plunger  72  and biases plunger  72  to its lowest position with piston head  78  seated in bore  70  above dosage chamber  68 . This lowest position is established by the engagement of O-ring  82  with wall  86 . At this time, lifting arm portion  142  of actuator arm member  138  is spaced below the underside of lip  152  of plunger head  150  as shown in FIG. 7A.  
         [0069]    When the user presses actuator button  124 , the bias of spring  128  is overcome and rod extension  134  and lifting arm portion  142  are lifted until lifting arm portion  142  engages the underside of plunger head lip  152 , as shown in FIG. 7B, causing plunger  72  to be lifted overcoming the bias of spring  74 . At the same time, arm portions  140  and  141  engage sloped or ramp surfaces  146  and  147  of screws  144  and  145 , respectively. This engagement causes lateral movement of arm member  138  away from plunger  72 , but, as shown in FIG. 7B, lifting arm portion  142  is not yet free of engagement with underside  152  of plunger head  150 . As is shown in FIGS.  6 B, lifting arm portion  142  has brought plunger  72  to a raised position while raising piston head  79  and enlarging dosage chamber  68 . This results in a drop in pressure within dosage chamber  68 . This drop in pressure to the left of ball  96 , when added to the positive pressure applied to the right side of ball  96  by liquid in passageway  88  by virtue of the pressure applied to collapsible bag  42  by spring finger  40 , is sufficient to overcome the bias of spring  98  and force valve ball  96  to move off O-ring  100  opening one-way valve  94 . Ophthalmic liquid  44  then flows from bag  42  into dosage chamber  68  to fill chamber  68  with the proper dosage of the eye drops to be sprayed into the user&#39;s eye.  
         [0070]    As actuator rod extension  134  is further raised, arm portions  140  and  141  slide further up ramp surfaces  146  and  147 , respectively. This causes arm portions  140  and  141  and, with them, actuator arm extension  134 , to move further away from plunger  72  until, as shown in FIG. 7C, head  150  becomes free of and disengaged from lifting arm portion  142 . At this time, bias spring  74  drives plunger  72  downwardly to move piston head  79  in a direction compressing dosage chamber  68 , as shown in FIG. 6C. As chamber  68  is compressed, the pressure within dosage chamber  68  increases forcing valve ball  108  of one-way valve  104  to overcome the bias of spring  110  and open one-way valve  104 . This permits the ophthalmic liquid to flow from dosage chamber  68  into outlet member  107  and thin walled outlet portion  116  into inlet passage  120  of nozzle  20 . Being under pressure, the liquid flows through nozzle  20  and pinholes  160  and is sprayed as eye drops into the user&#39;s eye.  
         [0071]    Movement of plunger  72  under the influence of bias spring  74  continues until plunger  72  is returned to the resting position of FIG. 6A. When O-ring  82  comes into contact with the portion of end wall  86  surrounding bore  87 , the impact is cushioned by the elastomeric material from which O-ring  82  is made.  
         [0072]    After lifting arm portion  142  is moved free of plunger head  150 , the user releases actuator button  124 . Bias spring  128  then moves actuator rod  126  and actuator rod extension  134  back to their resting positions as shown in FIGS. 6A, 7A and  8 .  
         [0073]    It will be observed that the quantity of ophthalmic liquid drawn into dosage chamber  68  is governed by the length of the upward stroke of plunger  72  and that the length of this upward stroke is determined by the placement of ramp surfaces  146  and  147 , which establish when arm lifting portion  142  is moved free of plunger head  150 . Thus, when the user presses actuator button  124 , a predetermined quantity of the ophthalmic liquid is drawn into dosage chamber  68  and the same predetermined quantity is sprayed as eye drops into the user&#39;s eye.  
         [0074]    Although the body of pump means  64 , in which bore  70  and dosage chamber  68  are formed, and plunger  72 , including flange  78 , piston head  79  and rod extension  80 , and actuator means parts  124 ,  126 ,  134  and  138  may be formed of metal, it is more economical, and therefore preferable, to form these parts of a plastic material, such as ABS or polypropelene. Because valve springs  98  and  110  are formed of stainless steel, there is no concern that these springs will be degraded by contact with the ophthalmic liquid flowing through the valves. However, bias spring  74 , which is shielded from the ophthalmic liquid in dosage chamber  68  by flange  78 , and bias spring  128 , which also does not come in contact with the ophthalmic liquid, may be made of a more economical resilient material, such as polythelene. O-rings  82 ,  84 ,  100 , and  112  may be formed of rubber or silicone rubber. Valve balls  94  and  108  may be formed of stainless steel, ABS, or polypropelene.  
         [0075]    A second embodiment of an eye drop dispensing system of the invention is shown in FIGS.  10 - 17 , wherein parts corresponding to identical parts in the embodiment of FIGS.  1 - 5  use identical reference numbers. The eye drop dispensing system  210  of the second embodiment includes a trough  12  having a front end wall  14  on which an arcuate eye piece  16  is formed. As is known in the art, eye piece  16  will be positioned on a user&#39;s face just below an eye to be treated.  
         [0076]    A spray space  18  is positioned in trough  12  behind wall  14 , and a spray nozzle  220  is located in spray space  18 . As will be explained in more detail below, spray nozzle  220  is mounted to receive ophthalmic liquid to be sprayed from three pumps,  64   a ,  64   b  and  64   c , located within a pump housing  222  located behind spray space  18 .  
         [0077]    A cartridge receiving space  24  (see FIGS. 11 and 12) is positioned behind pump housing  222 . In order to receive a cartridge housing  226 , the bottom wall  28  of cartridge receiving space  24  has a pair of guide grooves  30  and  31  (see FIG. 12) and side walls  32  and  34  (see FIG. 11) each of which has a guide groove  36  (only one of which is seen).  
         [0078]    Cartridge housing  226  comprises a top wall  38  (see FIG. 3) from which a spring finger  40  is cut, having a base portion  42  (see FIG. 10) connected to top wall  38  at the front end of housing  226 . As best seen in FIG. 12, spring finger  40  applies positive pressure to three collapsible bags or chambers  42   a ,  42   b  and  42   c  formed of a resilient material, such as silicone rubber, and containing the ophthalmic liquid.  
         [0079]    In order to provide access to liquid within chamber  42 , the front ends of collapsible bags  42   a ,  42   b  and  42   c  are provided with piercable entry walls  46   a ,  46   b  and  46   c  closing neck portions  47   a ,  47   b  and  47   c  of the collapsible bags. As seen in FIGS. 12, 16 and  17 , hollow needles  48   a ,  48   b  and  48   c  extend through openings  50   a ,  50   b  and  50   c  at the front end of housing  226 . Neck portions  47   a ,  47   b  and  47   c  of bags  42   a ,  42   b  and  42   c  are seated in openings  50   a ,  50   b  and  50   c.    
         [0080]    Cartridge housing  226  has parallel rails  52  and  53  (see FIG. 11) extending downwardly from its bottom wall and fitting in guide grooves  30  and  31 , respectively. Side rails  54  are provided on the outer surfaces of side walls  56  and  57 . These are received in respective side grooves  36 . The rear ends of side rails  54  are formed as resilient catches  58  to secure cartridge housing  226  in cartridge receiving space  24  by cooperating with posts  59  and notches  62  and  63  formed at the rear ends of side grooves  36 .  
         [0081]    Cartridge housing  226  is slid into cartridge receiving space  24  through an opening  60  at the rear end of trough  12  with rails  52 ,  53  and  54  engaged in guide grooves  30 ,  31  and  36 . When cartridge housing  226  is fully inserted, hollow needles  48   a ,  48   b  and  48   c  pierce piercable entry walls  46   a ,  46   b  and  46   c . In this way, ophthalmic liquid is made available for pump means within pump housing  22 . When cartridge housing  226  is fully inserted, resilient catches  58  engage notches  62  and  63  at the ends of grooves  36  to retain cartridge housing  226  in cartridge receiving space  24 .  
         [0082]    Pump means is received in pump housing  222  through an opening through the bottom wall of trough  12 . Three separate pumps  64   a ,  64   b  and  64   c  are included within pump means  64 .  
         [0083]    Turning to FIGS. 13, 14 and  15 , pump means  64   a  is shown as a shuttle pump and is identical to pump means  64   b  and  64   c . An outer shuttle chamber  230  has an inlet opening  232  connected to hollow needle  48   a  and has an outlet opening  234  connected to an outlet conduit  116   a  leading to an outlet opening  236   a  of nozzle  220 . An inner shuttle chamber  240  is positioned for reciprocation within outer shuttle housing  230  and has an inlet opening  242  on a side facing inlet opening  232  and an outlet opening  244  on a side facing outlet opening  234 . A plunger  250  is mounted on the end of a control shaft  252 . A control arm  254  is engaged with the free end of shaft  252  and is biased to an outward, retracted position, as shown in FIG. 13 by a bias spring  256  which is engaged at one end to an end wall  258  of outer shuttle chamber  230  and at the other end with control arm  254 . When, as will be explained below, control arm is depressed, as shown in FIG. 14, plunger  250  moves to compress the space in inner shuttle chamber  240  putting liquid within inner shuttle chamber  240  under pressure and forcing inner shuttle chamber to reciprocate in outer shuttle chamber  230  as shown in FIG. 14. As this movement continues, as shown in FIG. 15, outlet opening  244  is brought into alignment with outlet opening  234  pumping the liquid within inner shuttle chamber through conduit  116   a  and nozzle  220  into the user&#39;s eye. When the pressure on control arm  254  is released, spring  256  returns control arm  254 , control shaft  252  and plunger  240  back to the position shown in FIG. 13. This brings inlet opening  242  into alignment with inlet opening  232 . Since the movement of plunger  250  to its retracted position results in a drop in pressure within inner shuttle chamber  240 , the liquid within collapsible chamber  42   a  is drawn through needle  48   a  into inner shuttle chamber  240  ready to be dispensed into the user&#39;s eye the next time control arm  254  is depressed.  
         [0084]    The manner in which a single control member  224  simultaneously controls the three pumps is shown in FIGS. 16 and 17. The control member  224  extends outside trough  12  and is mounted at the end of a control rod  260 . A bias spring  262  is mounted between control member  224  and a wall of pump housing  222  and biases control member  224  and control rod  260  to an outward position shown in FIG. 16. Three control arms  254 ,  254   b  and  254   c  extend laterally from control rod  260  and are respectively engaged with control shafts  252 ,  252   b  and  252   c . As shown in FIGS. 13, 14 and  15  respective springs  256 ,  256   b  and  256   c  are engaged between the ends of outer shuttle chambers  230  and control arms  254 ,  254   b  and  254   c  to bias the control arms to a retracted position as shown in FIG. 16. When control member  224  is depressed by the user, control rod  260 , which mounted to slide on bearings  270  and  271 , is moved to move control arms  254 ,  254   b  and  254   c  in a direction to move plungers  250  as shown in FIG. 17. Thus, the actuation has the same effect as depressing three separate control arms simultaneously with the result that the prescription drug solutions in the respective collapsible containers and dispensed simultaneously into the user&#39;s eye.  
         [0085]    Although the second embodiment as shown employs shuttle pump means, the type of pump used may vary. For example, simple mechanical piston pumps or peristaltic pumps may be used.  
         [0086]    It should be understood that the foregoing description of the invention is intended merely to be illustrative and other modifications, embodiments and equivalents may be apparent to those skilled in the art without departing from the spirit and scope of the invention.