Cartridge for applying medicament to an eye

A cartridge for actuating a piston-like or accordion-like dispenser-vial for applying medicament to an eye. The cartridge includes a housing for holding the dispenser-vial and a telescoping cylinder for compressing the dispenser-vial in the longitudinal direction to actuate the vial. The cartridge includes a locking mechanism for locking the telescoping cylinder to restrict its movement and a lever mechanism for releasing the cylinder from the locked position so that a drop is released from the dispenser. The housing includes a finger for engaging the lower eyelid and exposing the conjunctival cul-de-sac.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a cartridge for applying medicament to an eye from 
a vial-dispenser of the type which is actuated by compression of the vial 
between its nozzle and its bottom wall. 
2. Description of Related Art 
There are various dispensers which are known for applying medicament to an 
eye. A typical eye-drop container includes a flexible vial storage portion 
and a nozzle for dispensing drops of medicament into the eye by squeezing 
the vial between its side walls. Less common, but more precise, are 
accordion-like or piston-like dispensers which are actuated by squeezing 
the vial between a bottom wall and the nozzle so as to compress the vial 
in its longitudinal direction, rather than from its sides. It is these 
accordion-like or piston-like dispensers with which the cartridge of the 
present invention is particularly adapted for use. An example of a new and 
improved piston-like dispenser which propels micro-drops into the eye is 
the subject of my U.S. application Ser. No. 07/801,243 which is expressly 
incorporated herein by reference. 
Most people encounter difficulty in applying drops to their eyes. The eye 
is a very sensitive body part and individuals find it difficult to control 
reflexive blinking when applying drops thereto. Also, eye drop users often 
have poor vision. Poor vision makes it difficult to position the tip of 
the dropper bottle over the eye and frequently causes drops to be 
incorrectly applied to the nose or cheek. Additionally, elderly people 
often have difficulty holding a dropper bottle steady or encounter 
difficulty in squeezing the bottle to apply a proper quantity of the 
medicament. 
Even if the liquid medicament is properly applied to the eye, the 
medicament's effectiveness is limited. The minimum volume of a drop of 
liquid medicament which can ordinarily be introduced into contact with an 
eye at one time is about 30 .mu.l. Any amount which is greater than about 
25 .mu.l usually spills over the eyelid onto the cheek since this is the 
maximum volume which the eye can ordinarily handle. When eye drops are 
applied to the surface of the eyeball, blinking and natural tear flow 
combine to limit the time to a few minutes that liquid medicament will 
remain effective. 
On the other hand, if medicament is applied to the cul-de-sac of the 
conjunctiva, the medicament will remain effective for a longer period of 
time, maximizing the benefits of applying drops of liquid medicament to 
the eye. This is because the conjunctiva is an area of low sensitivity and 
low tear turnover such that blinking and tearing are avoided. However, 
because of the difficulty encountered in steadying the dropper and 
accurately positioning it over the conjunctiva, maximizing the 
effectiveness of the medicament remains elusive. 
U.S. Pat. No. 4,543,096 describes and illustrates an apparatus having 
finger-like projections which are attached to the front of an eye drop 
bottle to spread the eyelids apart during the eye drop dispensing process. 
One moveable finger is connected to a lever for both depressing the lever 
and simultaneously causing the eyelids to spread apart while forcing a 
drop from the dropper bottle. However, the apparatus described in U.S. 
Pat. No. 4,543,096 cannot be used with the accordion-like or piston-like 
dispensers which are actuated by compression in the longitudinal direction 
rather than from the sides. Furthermore, this apparatus will not properly 
expose the cul-de-sac. 
Similarly, U.S. Pat. No. 4,531,944 depicts an apparatus for steadying the 
tip of a dropper over the eye and further includes a sighting hole to 
distract the eye. However, this apparatus does not have a means to expose 
the cul-de-sac nor keep the lower eyelid depressed. 
Typical eye-drop dispensers also have the disadvantage that the force which 
is necessary to actuate the dispenser to emit a drop is not in the same 
direction as the motion which is necessary to lower the lower eyelid and 
expose the cul-de-sac. It would be desirable to have a device which 
actuates the dispenser with a motion which is in the same direction as 
that which is necessary to lower the lower eyelid. 
U.S. Pat. No. 5,267,986 describes a device which meets all of the 
above-described needs. Additional improvements and variations on this 
device are described herein. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a device which can accurately 
deliver a small drop of medicament to the conjunctival cul-de-sac of an 
eye. 
It is a further object of the invention to provide such a device which can 
be used to actuate an accordion-like or piston-like vial-dispenser using 
minimal force. 
It is a further object of the invention to provide such a device wherein 
the motion used to actuate the dispenser to emit a drop is in the same 
direction as the motion which is necessary to depress the lower eyelid and 
expose the conjunctival cul-de-sac. 
It is a further object of the invention to provide a device having these 
features which has a simple construction and which is easy to manufacture. 
The foregoing objects are achieved by the present invention which provides 
a cartridge which is particularly adapted for actuating an accordion-like 
or piston-like dispenser-vial. The cartridge includes a generally 
elongated housing which is adapted to receive a dispenser-vial between an 
anterior wall of the housing and a telescoping cylinder. The anterior wall 
of the housing has an aperture for exposing the nozzle of the vial. The 
anterior of the housing may be provided with a cover, shutter or the like 
for closing the opening. The nozzle is preferably receded within the 
housing so that it does not project out of the opening so as to prevent 
any corneal injury in the event of accidental contact with the eye. 
The back of the housing has an opening which slidably receives the 
telescoping inner cylinder. When the inner cylinder is pushed toward the 
anterior of the housing it forces the dispenser-vial to compress in the 
longitudinal direction between the anterior wall of the housing and the 
cylinder. In the case of some dispensers which can be used with the 
invention, compression causes a drop of liquid medicament to enter the 
drop cavity of the dispenser thereby "loading" the drop cavity. 
The top of the inner cylinder has a surface defining one or more upwardly 
projecting teeth which are especially adapted to engage with an opposing 
tooth on a lever, to lock the inner cylinder in a plurality of different 
positions. Each tooth includes at least a first surface which is inclined 
with respect to the top surface of the inner cylinder, and a second 
surface which extends from the top of the first surface at an acute angle 
therewith toward the top surface of the inner cylinder where it terminates 
with the top surface, preferably at about a right angle. Thus, from the 
side, each tooth resembles a right triangle. 
The lever is preferably a fork having a pair of prongs (i.e., an upper 
prong and a lower prong) and a lever arm. The lever arm has a tooth which 
substantially corresponds in shape to the type of tooth belonging to the 
inner cylinder. The tooth of the lever arm extends downwardly in opposed 
relationship to the upwardly extending teeth of the inner cylinder. An 
upper prong is angled in the upward direction from a pivot point of the 
lever, and includes a raised area which defines a button. The button is 
exposed or projects out through an aperture in the top of the housing. A 
lower prong angles downwardly from the pivot point to come into contact 
with and rest upon a shelf which projects from the anterior wall or side 
wall of the housing toward the interior of the housing. 
When the posterior end of the inner cylinder is pushed anteriorly (i.e., 
toward the interior of the housing), the inclined surface of the tooth 
belonging to the inner cylinder will slide over the inclined surface of 
the tooth belonging to the lever arm and, in so doing, will urge the lever 
arm upward until the inclined surface of the tooth belonging to the inner 
cylinder has passed by the inclined surface of the tooth belonging to the 
lever arm. At this point, the lever arm will snap back downward due to the 
force exerted by the two prongs which are wedged between the shelf and the 
top wall of the housing. As the lever arm snaps downward, the second 
(e.g., normal) surface of its tooth will engage with the second surface of 
the tooth belonging to the inner cylinder, thereby locking the inner 
cylinder in place. In the case of some dispensers which can be used with 
the invention, the resulting compression of the dispenser in the cartridge 
causes a drop of liquid medicament to enter a drop cavity of the 
dispenser, thereby "loading" the drop cavity. 
Upon depression of the button belonging to the upper prong of the lever, 
the lever arm will be forced upward about the pivot point of the lever, 
and the second (e.g., normal) surface of its tooth will disengage from the 
second surface of the tooth belonging to the inner cylinder. Upon 
disengagement, the inner cylinder will be urged posteriorly (i.e., in the 
direction out of the housing) by the action of a bellows, spring or other 
biasing means which continually urges the inner cylinder to expand in the 
longitudinal direction, said expansion causing the posterior end of the 
inner cylinder to project out of the posterior end of the housing. The 
biasing means may belong to the inner cylinder itself, as well as to the 
dispenser. With some of the dispensers which can be used with the 
invention, decompression causes the drop of liquid which had previously 
entered the drop cavity to be emitted through the nozzle. 
Movement of the inner cylinder in the posterior direction is restricted by 
engagement of the second surface of the tooth belonging to the lever with 
the second surface of a second tooth belonging to the inner cylinder. 
Alternatively, or in addition, movement of the inner cylinder in the 
posterior direction may be restricted by cooperation between a posterior 
wall of the housing and a widened section of the inner cylinder which 
cannot fit through the opening in the posterior wall of the housing, or by 
a stop member in the housing which engages a tooth on a lower surface of 
the inner cylinder. 
For additional leverage, the lever may include a pair of laterally 
extending pins at the point where the upper and lower prongs meet with the 
lever arm (i.e., the pivot point). The laterally extending pins fit into 
corresponding bearings which are fixed to the interior of the housing. The 
lever will then be pivotable about these pins which are rotatable in the 
bearings. 
The lower section of the anterior section of the housing is formed with a 
soft finger which is adapted to engage the lower eyelid. Alternatively, 
the finger is a projection formed of the same material as the housing 
which can receive a sleeve of a soft material. 
In order to apply a drop of medicament, the inner cylinder is pushed into 
its locked position to load the dispenser-vial. The nozzle is then 
positioned over the eyeball with the finger pressing on the lower eyelid 
to expose the conjunctival cul-de-sac. When the button is depressed the 
resulting motion of the cartridge will be in the same direction as the 
motion which causes the finger to lower the lower eyelid and expose the 
conjunctival cul-de-sac as a drop is emitted.

DETAILED DESCRIPTION OF THE INVENTION 
The cartridge of the invention is specially adapted to work in conjunction 
with an accordion-like or piston-like dispenser-vial. An example of a new 
and improved piston-like dispenser which can be used in the cartridge of 
the invention is the subject of my application Ser. No. 07/801,243 which 
is expressly incorporated herein by reference, however, the present 
invention is not limited to use with this particular dispenser. Parts of a 
dispenser described in application Ser. No. 07/801,243 which are relevant 
to an understanding of the present invention are illustrated in FIGS. 5 
and 8 and will now be described briefly to facilitate understanding of the 
cartridge. 
The dispenser-vial generally depicted at 1 includes a nozzle 2, wing 3, a 
bellows portion 4, wing 6 and a rear vial section 8 containing a storage 
supply of liquid medicament. The dispenser is compressible in the 
longitudinal direction along the bellows. For this purpose, the bellows 
portion 4 is constructed of a soft flexible plastic material such as the 
thermoplastic resin sold under the trademark Kraton from the Shell 
Company. Resiliency of the dispenser can be provided by the spring quality 
of the accordion bellows made of "Kraton". "Kraton" has an excellent 
memory and can be an excellent spring. Alternatively, resiliency may also 
be provided by a longitudinally disposed spring (not illustrated) which 
urges the dispenser to expand upon compression. 
The dispenser includes a drop cavity therein (not illustrated) which holds 
a predetermined volume of fluid to be emitted in the form of a drop. 
Compression of the dispenser in its longitudinal direction creates a drop 
in pressure in the drop cavity to fill or "load" the drop cavity with 
liquid where it is stored until it is emitted as a drop from the nozzle 2. 
This compressed state will be referred to herein as the loaded state. 
Expansion of the dispenser from the loaded state (caused by the 
bellows-spring) urges the fluid in the drop cavity under pressure toward 
the nozzle 2 from which it is emitted in the form of a drop. It can be 
seen that the force which is required to actuate this type of dispenser 
must ordinarily be applied in the direction of the nozzle. With this 
background information about the operation of the piston-like dispenser in 
mind, the cartridge of the invention will now be described. 
Referring to FIGS. 1 and 2, the cartridge, which is generally indicated at 
10, includes a housing 16 which may be cylindrical or any other convenient 
shape to be hand held. The housing 16 includes side walls 12 and a 
posterior wall 14 which slidably receives an inner compressible member 18, 
which may be cylindrical, through a posterior aperture 20 therein. The 
posterior wall 14 has a close tolerance with respect to the inner cylinder 
18 to help close off the housing to the external environment. For this 
purpose, the posterior section of the inner compressible member 18 may 
include one or more ribs 19 whose shape matches that of the posterior 
aperture 20, the ribs being positioned so that they fit flush against the 
posterior wall 14 to close aperture 20 in the rest position of the 
cartridge. 
The front of the housing 16 is substantially closed by an anterior wall 22 
which has an aperture 24 centrally located therein allowing for the 
exposure of the nozzle 2 of the dispenser. Preferably, the cartridge is 
dimensioned such that a dispenser can fit snugly therein with its nozzle 
completely receded within the aperture 24 of anterior wall 22. In this 
way, accidental contact of the nozzle with the eye is not possible, which 
avoids injuries, as well as contamination of the outside of the nozzle. 
The inner cylindrical member 18 includes a spring or bellows portion 25. 
The spring 25 is situated between a posterior section 26 of the 
cylindrical member and an anterior section 27 of the cylindrical member. 
When the medicament dispenser 1 is mounted in the cartridge, it is first 
fit within the inner cylindrical member 18 in the manner which will be 
described hereinafter. Since the wing 6 of the dispenser 1 must be 
compressed in the longitudinal direction to become loaded, it must be 
somehow fixed within the inner cylindrical member 18. For this purpose, 
the anterior section 27 includes an inwardly projecting rim 28 which 
engages the wing portion 3 of the dispenser (see FIGS. 7 and 8). The rim 
28 is disposed anteriorly to the wings 3 to prevent the wings from moving 
forward when the inner cylindrical member 18 is pushed inward, as will be 
described hereinafter. The anterior section 27 of the inner cylindrical 
member 18 preferably also includes a pair of posteriorly extending 
projections 29, each projection having a tooth 30 at the posterior end 
thereof. The distance between each tooth 30 and the rim 28 should 
approximate the width of the wing 3, such that the wing 3 can be wedged 
snugly between the teeth 30 and the rim 28. The cooperation of teeth 30 
and rim 28 will maintain the dispenser 1 in the inner member 18 in a fixed 
position suitable for compression as well as expansion. 
The posterior end of the spring portion 25 is connected to an insert member 
31 (see FIGS. 6-8). The insert member 31 is adapted to fit into an 
anterior opening of the posterior section 26 of the inner cylindrical 
member 18. The insert portion 31 has an outwardly projecting rim 32, which 
engages the posterior section 26 for defining the limit of motion of the 
insert portion in the opening of the posterior section 26. The insert 
portion 31 includes two posteriorly projecting tab portions 33 which fit 
around the vial section 8 of the dispenser. The insert portion 31 also 
includes an inwardly projecting rim 34 which engages the wing 6 of the 
dispenser 1 when the dispenser is inserted into the inner cylindrical 
member 18. Preferably, the anterior section 27, spring 25, projections 29, 
insert portion 31 and tabs 33 are integrally molded as a single structure, 
separate and apart from the posterior section 26 of the inner cylindrical 
member. 
The dispenser 1 is easily inserted into the inner cylindrical member 18 of 
the cartridge of the invention as follows. The anterior section 27, spring 
25, insert member 31 and tabs 33 are separable from the posterior section 
26 of the inner cylindrical member 18. The nozzle 2 of the dispenser is 
fed through the tabs, through the insert portion 31 through the inwardly 
projecting rim 34, between the spring members 25, between the projections 
29 and through the rim 28 toward the anterior end of the anterior section. 
The space defined inside the rim 34 is large enough to allow the wing 3 to 
clear passed it. Each tooth 30 (see FIG. 10) has an inclined surface 35 
which allows the wing 3 to slide over each tooth as the dispenser is fed 
into the anterior section 27 as described above. However, each tooth also 
has a surface 36 which is normal or otherwise angled to the projection 29 
to which it belongs to act as a stopper for preventing wing 3 from passing 
over it so as to retain the dispenser in the anterior section 27. This 
normal surface 36 is anterior to the inclined surface 35 and will engage 
the wing 3 once the wing 3 has slid passed the teeth. It will be 
appreciated that the pair of projections 29 will flex outwardly as the 
wing 3 slides passed the teeth. However, the projections 29 will snap back 
inwardly once the wing 3 has cleared the teeth. The wing 3 will now be 
held in place between the rim 28 and the surfaces 36 of the teeth 30 (see 
FIG. 8). In this position, the wing 6 of the dispenser will engage the 
inward rim 34 of the insert portion 31, and the tabs 33 will be positioned 
around the vial section 8 of the dispenser (see FIG. 8). 
The anterior section 27, spring 25 and insert portion 31, having the 
dispenser 1 locked therein, are now ready to be coupled to the posterior 
section 26 of the inner cylindrical member 18. The tabs 33 facilitate 
guiding of the combination dispenser and anterior section into the 
posterior section 26. The insert member 31 is completely inserted within 
the posterior section 26 when the outwardly projecting rim 32 engages the 
posterior section 26. The posterior end of the posterior section 26 is 
closed to provide an additional barrier for the vial portion 8 of the 
dispenser against the external environment (e.g., oxygen, water moisture, 
CO.sub.2, etc.). 
The thus assembled inner telescoping member 18 containing the dispenser is 
situated within the housing 16. Preferably, the spring portion 25 of the 
inner cylindrical member 18 is a flexible, but resilient, plastic material 
which, when compressed in the longitudinal direction, will exert an 
expanding force. The housing 16 may be molded by conventional plastic 
molding techniques, and is preferably molded as two, snap-fittable half 
sections along its longitudinal axis so that the inner cylindrical member 
18 containing the dispenser 1 may be easily situated therein. The two half 
sections are molded by conventional techniques so that they can be 
securely snapped together (e.g., by engagement of snap-fit members 11 on 
one of the half sections into female receptors (not illustrated) on the 
other half section to close the housing. 
The interior of the housing 16 includes a pair of retaining-guiding shelves 
37 which project from the side walls 12 to the interior of the housing. 
The shelves 37 function to guide the inner cylindrical member 18 for 
compression and expansion in the longitudinal direction within the 
housing, but restrict any movement in directions transverse to the 
longitudinal axis. The inner cylindrical member 18 is mounted between the 
anterior wall 22 and the posterior wall 14 of the housing, with a portion 
38 of the inner member 18 projecting outside of the housing through the 
posterior aperture 20 in the rest state. 
The top surface of the posterior section 26 of the inner compressible 
member 18 defines one or more teeth 40 which, in cooperation with an 
opposing tooth 50 of a lever 43, allow for the adjustment of the inner 
compressible member 18 to various positions. Each tooth 40 includes at 
least a first surface 41 which is inclined with respect to the top surface 
of the posterior section 26, and a second surface 42, which extends from 
the end of the first surface 41 toward the posterior section 26 to define 
an acute angle with the first surface 41. Preferably, the second surface 
42 is about normal to the top surface of the posterior section 26. 
The cartridge includes a lever generally depicted at 43 for releasably 
locking the inner compressible member 18 in a variety of different 
positions. The lever 43 includes a lever arm 44, a lower prong 45 and an 
upper prong 46. The lower and upper prongs 45, 46 are wedged between shelf 
47 and top wall 48, respectively, of the housing 16. Shelf 47 projects 
inwardly from the side wall 12 and/or the anterior wall of the housing. 
The prongs 45, 46 are joined to the lever arm 44 at a pivot point 49. The 
posterior end of the lever arm 44 defines a tooth 50 which has 
substantially the same configuration as the teeth 40 belonging to the 
inner compressible member 18. Tooth 50 has a first, inclined surface 51 
which is angled so as to be able to make smooth sliding contact with 
inclined surface 41 of tooth 40. Tooth 50 also has a second surface 52 
which is adapted to engage the second surface 42 of one of teeth 40. 
Preferably, second surface 52 is about normal to the lever arm 44, but in 
any event is angled so as to engage the second surface 42 of tooth 40 to 
prevent that surface from sliding past it. 
The pivot point 49 of the lever 43 includes a pair of laterally extending 
pivot pins 53. Each pivot pin 53 is adapted to be rotatably received 
within a bearing 61 (see FIG. 9) provided on the interior of the side 
walls 12 of the housing 16. The pivot pins 53 are rotatable within the 
bearings for allowing the lever to pivot about the pivot point 49. 
The upper prong 46 of the lever 43 includes an elevated section 54 for use 
as a push button. The push button 54 is exposed to the user through an 
opening 62 (see FIG. 9) in the top of the housing 16. 
The significance of the structure of the teeth 40 and 50, and the 
cooperation thereof, will now be explained with reference to the operation 
of the cartridge. Referring to FIG. 3, the cartridge is illustrated in the 
rest position. In this position, it can be seen that the second surface 52 
of tooth 50 acts as a stop member for preventing the second surface 42 of 
one of the adjacent, anteriorly positioned teeth 40 from traversing over 
it in the posterior direction, thereby preventing the inner compressible 
member 18 from sliding out of the housing 16 through the posterior 
aperture 20. For this purpose, a stop member 54 may also be provided on 
the bottom of the housing 16 for engaging teeth 55 which may be optionally 
provided on the bottom surface of the posterior section 26. 
In order to load the dispenser 1 contained in the inner member 18, the user 
presses on the posterior end of the inner compressible member 18 to force 
it to compress in its spring region 25 in the housing 16. During this 
motion, the first surface 41 of the most posterior of the teeth 40 will 
slide over the first surface 51 of tooth 50 of the lever 43. In so doing, 
the lever arm 44 will be forced to pivot upwardly until surface 41 clears 
surface 51. At this point, the lever arm 44 will be free to snap back into 
its original position, resulting in engagement of surface 42 of the most 
posterior tooth 40 with surface 52 of tooth 50. As explained above, the 
engagement of surface 42 with surface 52 locks the inner member 18 in 
position. This is the loaded position which is illustrated in FIG. 4, 
wherein the spring or bellows 25 is compressed. It is in this position 
that a drop of medicament has been loaded into the drop cavity of the 
dispenser 1 as described above. 
In order to emit the drop, the user simply depresses push button 54 of the 
upper prong 46 of the lever 43. This will result in the lever arm 44 
pivoting upward about the pivot point 49, until surface 52 has cleared 
surface 42 of the most posterior tooth 40. The inner compressible member 
18 will then be free to expand by the force exerted by the spring 25 (and 
bellows 8 of the dispenser) back to its rest position illustrated in FIG. 
3. Upon expansion of the bellows portion of the dispenser 1 in the 
compressible member 18, a drop of medicament will be emitted from the 
nozzle as discussed above. 
The inner compressible member 18 may be formed with three teeth 40 in order 
to allow for the cartridge to originally (i.e., prior to first use) assume 
a third position, which will be referred to as a shelf life position. The 
optional third tooth is the most anterior of the teeth 40 illustrated in 
FIGS. 2-4. The shelf life position is illustrated in FIG. 2 where it can 
be seen that the tooth 50 is wedged between the most anterior of the teeth 
40 and the middle of the teeth 40. In this position, the inner 
compressible member 18 projects out from the posterior aperture 20 to a 
greater extent than in the rest position illustrated in FIG. 3, and the 
anterior end 56 of the anterior section 27 of the inner compressible 
member 18 is spaced away from the anterior wall 22. Thus, if someone were 
to accidentally push in the inner compressible member 18, the spring 25 
would not initially compress because of the space between the anterior 
section 27 and the anterior wall 22. This space will not be used up until 
the tooth 50 is wedged between the middle of the teeth 40 and the most 
posterior of the teeth 40 (i.e., the rest position). Thus, the shelf life 
position is designed to prevent accidental loading of the dispenser in the 
event that the inner compressible member 18 is accidentally engaged. 
In addition, in the shelf-life position, a rib 19 will be exposed to view 
(see FIG. 2) indicating to the user that the device has never been used 
before. If rib 19 is not exposed as in FIG. 2, the purchaser will know 
that the cartridge has been previously used, and possibly tampered with. 
This is because once the cartridge has been used for the first time, it 
cannot be placed back into the shelf-life position due to the engagement 
of the second surface of the tooth 50 of the lever with the second surface 
of the middle one of the teeth 40 in the rest position (see FIG. 3), or 
engagement of one-way stop member 54 with a tooth 55. As can be seen from 
the drawings, one-way stop member 54 is angled such that it permits 
sliding of the first surface of the tooth 55 inward (i.e., anteriorly), 
but engages the second surface of tooth 55 in the rest position to prevent 
return of the inner member 18 to the shelf-life position. 
The lower anterior section of housing 16 includes a forwardly projecting 
finger 57 which extends from the housing 16 in the anterior direction 
beyond anterior wall 22. The finger 57 can be an integral extension of 
housing 17, in which case it is preferably covered with a soft sleeve (not 
illustrated) for engaging the eye. The finger is preferably coated with a 
material such as Kraton. 
The housing 16 may include a cover 58 for closing the aperture 24 which 
ordinarily exposes the nozzle 2. The cover 58 is swingable by a hinge 59 
which is rotatably mounted on a hinge pin 60, which in turn is supported 
by the side walls 12 of the housing. 
It should be appreciated that one advantage of the cartridge of the 
invention is that the motion which is used to depress the push button 54 
and thereby release a drop is in the same direction as the motion used to 
lower the eyelid and expose the cul-de-sac with finger 57. Therefore, more 
accurate delivery of the drop is possible. Furthermore, an area of low 
sensitivity and low tear turn over is specifically targeted by the 
cartridge which prevents tearing and blinking reflex for better efficacy. 
In addition, there is no danger of poking the eyeball with the nozzle 2 
since the motion to depress the trigger is not in the direction of the 
eye, since the nozzle is preferably receded within housing 16, and since 
the finger 57 extends beyond the nozzle. Moreover, when the trigger is 
depressed, the return mechanism of the vial projects the inner cylinder 18 
in the direction away from the eye. The cartridge is particularly useful 
for arthritic patients because the push button mechanism allows for easy 
release of a drop. 
In the foregoing specification, the invention has been described with 
reference to specific exemplary embodiments thereof. It will, however, be 
evident that various modifications and changes may be made thereunto 
without departing from the broader spirit and scope of the invention as 
set forth in the appended claims. For example, the teeth 40 may be 
replaced with a plurality of notches defined in outer surface of inner 
member 18, the notches being engageable with tooth 50. Alternatively, 
teeth 40 may be retained as described herein and tooth 50 may be replaced 
with a notch which is engageable with teeth 40. The specification and 
drawings are accordingly to be regarded in an illustrative rather than a 
restrictive sense.