Abstract:
A method of safely delivering an ophthalmic fluid to an eye, the method including targeting the eye with an ophthalmic fluid misting device and activating an ultrasonic generator to deliver the ophthalmic fluid from the ophthalmic fluid misting device across a space between the misting device and the eye. The method further including maintaining a momentum of the ophthalmic fluid that is insufficient to trigger at least one of the ocular blink reflex and the lacrimation reflex of the eye.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional application of U.S. patent application Ser. No. 10/851,611, filed on May 20, 2004, now U.S Pat. No. 7,883,031 which claims priority under 35 U.S.C. §119(e) to both U.S. Provisional Application No. 60/485,305, filed on Jul. 3, 2003 and U.S. Provisional Application No. 60/471,883, filed on May 20, 2003, wherein each of the above mentioned U.S. Patent and U.S. Provisional Applications are incorporated herein by reference. 
    
    
     FIELD OF INVENTION 
     The present invention relates to drug delivery devices for dispensing liquid as an aerosol or atomized mist and, more particularly, for dispensing medicaments to the eye. 
     BACKGROUND OF THE INVENTION 
     Presently, conventional eye drops are the standard means of delivering medicaments to the eye. This means of ophthalmic drug delivery, however, has numerous problems. For example, the average eye drop (approximately 50 micro liters) far exceeds the eye&#39;s capacity (7 micro liters in the pre-corneal tear film and a maximum of about 30 micro liters in the lower cul-de-sac) effectively destabilizing and stripping the natural tear film. This results in a brief period of massive over-dosage, which is quickly cleared by reflex lacrimation, blinking and nasolacrimal drainage, resulting in sub-therapeutic drug levels until the next medication application. This approach represents very inefficient pharmacokinetics. Far smaller volumes of medicament (approximately one tenth of a conventional drop) are desirable and are, in fact, retained by the eye and “bio-available” for a substantially longer time. 
     Attempts to prolong ocular contact time by various adaptations, such as the use of particulate suspensions, have led to other drawbacks including ocular irritation and excessively slow drug release. Ointments and gels, though providing prolonged contact time, create obvious visual disturbances. 
     Further, local irritations and toxicities often result from the regular use of eye drops. These situations vary widely depending on the pharmacologic agent, preservatives and other additives being used, but this is clearly a very non-physiologic and inefficient system of medication administration. Chronic use of eye drops for such conditions as glaucoma and prolonged infections and inflammations can, in fact, cause substantial morbidity. Additionally, serious and even fatal reactions to sympathomimetic and beta-adrenergic blocking agents have occurred as a result of systemic absorption of eye drops via nasolacrimal drainage. 
     Besides the above issues, there are a great many difficulties that patients experience with the mechanics of eye drop administration. Elderly patients, the largest group of eye drop users, often have hand-eye coordination problems, tremors or arthritis, affecting the hands and/or the cervical spine, making eye drop administration difficult if not impossible. Many users report that they have trouble keeping track of their regimens and often repeat doses or miss them entirely, suffering potential consequences in either event. Further, pediatric patients, often unable to comprehend the reasons and benefits behind the administration of eye medication, often fight such application, typically resulting in underdosing due to the patient&#39;s attempts to prevent the eye drops from being administered, or overdosing, as a result of the administrator&#39;s attempt to ensure that sufficient dosage is being applied. 
     Additionally, very few regular users of eye drops, in any age group, actually observe the ideal technique of administration, including tear sac compression, to minimize excretory loss and potential systemic absorption. It is sometimes difficult to tell if the drop was properly instilled. Direct application to the cornea can result in the drop “bouncing” from the eye with little or no benefit. 
     Regular eye drop users commonly report using several drops which “missed” the eye until they are sure they properly instilled the drop. Also, many eye drop bottles are fabricated in such a way that loss is unavoidable as soon as the dropper is tilted. Finally, a significant number of regular users put another drop or two in the eye “just to be sure”. All of the above represent needless waste of expensive medication (many glaucoma medications cost $70-$80 for a 5 ml bottle) and also increased the risk of side effects, while actually reducing the therapeutic benefit. 
     The ophthalmic literature is rife with references to the need for a better means of ophthalmic drug delivery. With an estimate of 25 million users of eye drops in the united states alone, the magnitude of the public health issue is considerable. Accordingly, a new means of ophthalmic drug delivery is needed. 
     The concept of “spraying” medicated solutions on to the eye is not a new one. A number of devices have been conceptualized and developed for this purpose. Various means of atomizing and propelling solutions including mechanical pumps, gas-propelled jets and pistons, etc. Which have inherent drawbacks relating to difficulties with calibrating the flow velocity, volume and particle size of the emitted spray. See, for example, U.S. Pat. Nos. 3,170,462; 5,630,793; and 6,062,212. 
     It is hypothesized that the generated mist will expand and “therapeutically alter” but not significantly disrupt the physiologic tear film allowing for a more natural process in the transmission of therapeutic agents to the surface and the interior of the eye. A much smaller volume of solution can be administered below the blink and lacrimation thresholds, allowing for a prolonged time of application. The aggregate administration of a drug in thousands of 5-micron particles should significantly exceed that of a single eye drop, leading to greater concentrations of the drug (bioavailability). Furthermore, the surface tension of a standard drop is a barrier to “mixing” and tear film incorporation. This problem is expected to be avoided with micronebulization. 
     An additional benefit to mist administration of eye medications is the avoidance of dropper bottle contamination which commonly occurs from contact with the eyelid. In the professional office setting, this problem has led to many documented epidemics of viral keratoconjunctivitis. During medication administration via a dropper bottle to a patient with viral keratoconjunctivitis, the bottle tip may inadvertently touch the eye or eyelid of the affected patient, transferring the virus to the bottle tip. Subsequent medication administrations to other patients using the same dropper bottle transmits the virus to those patients. 
     Some of the beneficial features of an ophthalmic medication spray dispenser include the following: great ease of use; can be used in any “attitude” (i.e. With patient sitting, erect, lying down, head tilted back, etc.); abbreviated treatment cycle as compared to eye drop usage; improved bioavailability/efficacy; improved safety (reduced local and systemic side effects); improved sterility; increased compliance due to ease of use and “alert” systems; possibility of singular efficacy in the treatment of certain vision threatening infections; conservation of material (reduced volume, diminished waste/loss); and system (fixation target to help ensure proper application). 
     It would be beneficial to provide a system for applying the desired small amounts (7 to 10 micro liters) of optical medication, along with at least some of the above-listed beneficial features, while eliminating the drawbacks associated with previous means of drug delivery. 
     BACKGROUND 
     Briefly, the present invention provides a fluid atomizer comprising a body having a proximal end and a distal end. A removable reservoir is connected to the body, wherein the reservoir contains a fluid disposed therein. A discharge plate is disposed at the distal end, wherein the discharge plate includes a plurality of openings extending therethrough. The atomizer further comprises propulsion means for transmitting the fluid from the reservoir to the discharge plate and through the plurality of openings, wherein transmission of the fluid through the plurality of openings atomizes the fluid. 
     Also, the present invention provides a fluid atomizer comprising a body having a proximal end and a distal end. A removable reservoir is connected to the body, wherein the reservoir contains a fluid disposed therein. A discharge plate is disposed at the distal end, wherein the discharge plate includes a plurality of openings extending therethrough. The atomizer further comprises propulsion means for transmitting the fluid from the reservoir to the discharge plate and through the plurality of openings, wherein transmission of the fluid through the plurality of openings atomizes the fluid. The atomizer also includes a system controller electronically connected to the propulsion means, wherein the system controller controls operation of the propulsion means. 
     Further, the present invention provides a fluid atomizer comprising a body having a proximal end and a distal end. A removable reservoir is connected to the body, wherein the reservoir contains a fluid disposed therein. A discharge plate is disposed at the distal end, wherein the discharge plate includes a plurality of openings extending therethrough. The atomizer further comprises propulsion means for transmitting the fluid from the reservoir to the discharge plate and through the plurality of openings, wherein transmission of the fluid through the plurality of openings atomizes the fluid. The atomizer also includes a means for spacing the discharge plate a predetermined distance from a target. 
     Additionally, the present invention provides a fluid atomizer comprising a body having a proximal end and a distal end. A removable reservoir is connected to the body, wherein the reservoir contains a fluid disposed therein. A discharge plate is disposed at the distal end, wherein the discharge plate includes a plurality of openings extending therethrough. The atomizer further comprises propulsion means for transmitting the fluid from the reservoir to the discharge plate and through the plurality of openings, wherein transmission of the fluid through the plurality of openings atomizes the fluid. The atomizer also includes a system controller electronically connected to the propulsion means, wherein the system controller controls operation of the propulsion means. The atomizer also includes a means for adjusting operation of the propulsion means to adjust an amount of the fluid transmitted across the discharge plate, wherein the means for adjusting operation of the propulsion means are operatively connected to the system controller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate the presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention. In the drawings: 
         FIG. 1  is a side elevational view, partially broken away, of a mist spraying device according to a first embodiment of the present invention. 
         FIG. 2  is an exploded view of the device of  FIG. 1 . 
         FIG. 3  is an enlarged side profile view of a first embodiment of a fluid reservoir connected to the device. 
         FIG. 4  is a side profile view showing the device being used to spray a mist into a patient&#39;s eye. 
         FIG. 5  is a side profile view of the first embodiment of the fluid reservoir shown in  FIG. 3 , having been removed from the device. 
         FIG. 6  is an enlarged side profile view of a second embodiment of a fluid reservoir. 
         FIG. 7  is an enlarged side profile view of a third embodiment of a fluid reservoir. 
         FIG. 8  is a perspective view of the reservoir of  FIG. 7 . 
         FIG. 9  is an enlarged side view, in section, of a prime mover inserted into the device. 
         FIG. 10  is an enlarged exploded perspective view of a nozzle assembly of the device. 
         FIG. 11  is an enlarged side view, in section, of the nozzle assembly of the device. 
         FIG. 12   a  is an enlarged partial sectional view of a first embodiment of the mesh plate of the nozzle assembly. 
         FIG. 12   b  is an enlarged partial sectional view of a second embodiment of the mesh plate of the nozzle assembly. 
         FIG. 12   c  is an enlarged partial sectional view of a third embodiment of the mesh plate of the nozzle assembly. 
         FIG. 12   d  is an enlarged partial sectional view of a fourth embodiment of the mesh plate of the nozzle assembly. 
         FIG. 13   a  is a top plan view of a first embodiment of a mesh plate. 
         FIG. 13   b  is a top plan view of a second embodiment of a mesh plate. 
         FIG. 13   c  is a side view, in section of a third embodiment of a mesh plate. 
         FIG. 13   d  is a side view, in section, of a fourth embodiment of a mesh plate. 
         FIG. 13   e  is an enlarged partial sectional view of a fifth embodiment of a mesh plate. 
         FIG. 14  is a perspective view of the device showing an optional dosage adjustment feature. 
         FIG. 15   a  is a perspective view of the device showing a first embodiment of the dosage adjustment feature. 
         FIG. 15   b  is a perspective view of the device showing a second embodiment of the dosage adjustment feature. 
         FIG. 15   c  is a perspective view of the device showing a third embodiment of the dosage adjustment feature. 
         FIG. 16  is a top plan view showing the targeting device of  FIG. 14 . 
         FIG. 17   a  is a schematic view of a first embodiment of a targeting mechanism showing the device too close to the target. 
         FIG. 17   b  is a schematic view of the first embodiment of the targeting mechanism showing the device a correct distance from the target. 
         FIG. 17   c  is a schematic view of the first embodiment of the targeting mechanism showing the device too far from the target. 
         FIG. 18   a  is a schematic view of a second embodiment of a targeting mechanism showing the device too close to the target. 
         FIG. 18   b  is a schematic view of the second embodiment of the targeting mechanism showing the device a correct distance from the target. 
         FIG. 18   c  is a schematic view of the second embodiment of the targeting mechanism showing the device too far from the target. 
         FIG. 19   a  is a schematic view of a third embodiment of a targeting mechanism showing the device too close to the target. 
         FIG. 19   b  is a schematic view of the third embodiment of the targeting mechanism showing the device a correct distance from the target. 
         FIG. 19   c  is a schematic view of the third embodiment of the targeting mechanism showing the device too far from the target. 
         FIG. 20   a  is a schematic view of a fourth embodiment of a targeting mechanism showing the device too close to the target. 
         FIG. 20   b  is a schematic view of the fourth embodiment of the targeting mechanism showing the device a correct distance from the target. 
         FIG. 20   c  is a schematic view of the fourth embodiment of the targeting mechanism showing the device too far from the target. 
         FIG. 21   a  is a schematic view of a fifth embodiment of a targeting mechanism showing the device too close to the target. 
         FIG. 21   b  is a schematic view of the fifth embodiment of the targeting mechanism showing the device a correct distance from the target. 
         FIG. 21   c  is a schematic view of the fifth embodiment of the targeting mechanism showing the device too far from the target. 
         FIG. 22   a  is a side elevational view of a mechanical targeting device according to the present invention. 
         FIG. 22   b  is a top plan view of a proximal end of the mechanical targeting device shown in  FIG. 22   a , being used on a patient. 
         FIG. 23  is a schematic view of an electronic control system for the device. 
         FIG. 24  is a perspective view of an alternative embodiment of the device according to the present invention. 
         FIG. 25  is a perspective view of another alternative embodiment of the device according to the present invention. 
         FIG. 26  is a perspective view showing self-administration of medication using the device. 
         FIG. 27  is a perspective view showing administration of medication by one person to another using the device. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Certain terminology is used in the following description for convenience only and is not limiting. As used herein, the term “distal” is meant to mean the discharge end of the inventive device and the term “proximal” is meant to mean the end of the inventive device held by user. The terminology includes the words above specifically mentioned, derivatives thereof and words of similar import. The embodiments illustrated below are not intended to be exhaustive or to limit the invention to the precise form disclosed. These embodiments are chosen and described to best explain the principle of the invention and its application and practical use and to enable others skilled in the art to best utilize the invention. 
     The present invention provides a novel device and method for ophthalmic drug delivery. In preferred embodiments, the present invention provides a small, hand-held, battery or ac powered device that nebulizes liquid eye medications into a fine mist. The mist from the device is directed at the eye to be treated and the drug is delivered via the mist. 
     A preferred means of forming the mist is by ultrasound energy generated by a piezoelectric transducer or other suitable piezo device. A small plume of nebulized solution is generated, consisting of particles measuring what is believed to be an average of about five microns in diameter. The volume of each emission is dependent on the rate of mist generation (typically measured in micro liters per second) as well as the duration of the operation of the device, which may be easily varied by using an electronic control circuit. The shape, dimensions and focus of the emitted mist are proportioned for delivery to the human eye. The momentum of the mist is subliminal to the ocular blink and lacrimation reflexes and may also create a soothing sensation in the eye. The device is equally efficient when used in any “attitude” from a natural, upright head posture to leaning forward or lying back. Application time is significantly abbreviated compared to eye drop usage, which typically requires several maneuvers and careful attention to detail to ensure proper administration. 
     One preferred embodiment of the invention is now described with reference to  FIGS. 1 and 2 , which show a hand held device  100  that directs a mist of drug to an eye for treatment. As will be described in more detail below, the device  100  includes a vial or reservoir  120  of the fluid to be delivered to the eye, such as a drug. The user holds the device  100  and, by operating an activation switch, causes the device  100  to generate a mist of the liquid, which is discharged from the head portion  110  of the device  100 . The user simply aims the head of the device at the target eye to allow the mist to contact the eye. 
     Referring to  FIGS. 1 and 2 , the major components of the device  100  are shown. The components include a head portion  110  and a handle portion  160 . The head portion  110  preferably contains, from a proximal to a distal direction, a fluid reservoir  120  to retain a fluid  122  to be administered, a body  130  that houses a prime mover  140  to draw the fluid from the reservoir  120  and propel the fluid  122  out the distal end of the device  100 , and a nozzle assembly  150  which aerosolizes the fluid  122  and to form a mist pattern of the fluid  122  as the fluid  122  is directed toward its target. The handle portion  160  preferably contains the power source  170 , such as a battery, an activation switch  180  to activate the device, and a system controller  190  that controls the various operational aspects of the device  100 . 
     Head Portion 
     The head portion  110  includes the body  130  that connects the reservoir  120 , the prime mover  140 , and the nozzle assembly  150  together. The head portion  110  is connected to the handle portion  160  and provides a conduit for electrical leads (not shown) extending from the reservoir  120  and the prime mover  140  to the system controller  190 . 
     Reservoir 
     Referring to  FIG. 3 , in which an enlarged view of a preferred embodiment of the reservoir  120  is shown, the fluid reservoir  120  may can be a vial pre-filled with the fluid  122  to be delivered to the eye. The reservoir  120  may incorporate a scale comprising a clear window  123  with volume graduation markings  124  to indicate fill level or doses of fluid  122  remaining in the reservoir  120 . In the present embodiment, the scale is read with the device  100  standing on its base  166 , as shown in  FIG. 1 . 
     The reservoir  120  is preferably shaped to maintain contact with the prime mover  140  when the device  100  is held in a preferred operational orientation while spraying into an eye (as shown in  FIG. 4 ), or is tilted in any direction within 45 degrees of horizontal. The reservoir  120  is preferably further shaped to maximize the percentage of the total fill volume that is actually dispensed. 
     Referring back to  FIG. 3 , the reservoir  120  houses the fluid  122  that is used to form the aerosolized mist when the device  100  is operated. The reservoir  120  is preferably a removable and replaceable cartridge  126  that is securably connectable to the body  130  so that the reservoir  120  does not accidentally readily separate from the body  120 , yet is easily replaceable when the reservoir  120  is empty or when a reservoir  120  containing a different type of fluid is desired to be connected to the device  100 . 
     Preferably, the reservoir  120  includes an engagement surface  128  disposed proximate to an upper and a lower side of the reservoir  120 . The engagement surface  128  slides over a corresponding extension in the body  130 , as shown in  FIG. 3 , so that the reservoir  120  is retained onto the body  130  with a frictional fit. Preferably, the extension includes a plurality of seals, such as o-rings  134 , that provide a sealing engagement between the reservoir  120  and the body  130  and assists in frictionally retaining the body  120  to the reservoir  130 . Alternatively, the reservoir  120  may connect with the body  130  by other means known to those skilled in the art, including, but not limited to, threaded connections, bayonet fittings, or other suitable means. 
     In the embodiment shown in  FIG. 5 , which shows the reservoir  120  removed from the remainder of the device  100 , the reservoir  120  includes an open face  1210  that is covered by an air impermeable seal  1212 . Initially, the open face  1210  allows the fluid  122  to be deposited into the reservoir  120 , and then sealed with the seal  1212 . Such a seal  1212  may be constructed from thin gauge aluminum, or some other suitable material, with a biocompatible coating disposed on both faces of the seal  1212 . The seal  1212  is attached to the reservoir  120  with a biocompatible adhesive. The seal  1212  is designed to maintain sterility of the fluid  122  within the reservoir  120 , yet be able to be easily punctured by the proximal end  142  of the prime mover  140  upon connecting the reservoir  120  to the body  130  so that the fluid  122  in the reservoir  120  is put into fluid communication with the proximal end  142  of the prime mover  140 , as shown in  FIG. 3 . 
     For a reservoir  120  having a rigid form, such as the reservoir  120  shown in  FIG. 5 , a vent  1214  is formed in the wall of the reservoir  120 , preferably proximate to the top of the reservoir  120 , to allow air to be drawn into the reservoir  120  to compensate for the loss volume of fluid  122  as the fluid  122  is drawn out of the reservoir  120  due to operation of the device  100 . A filter  1216  covers the vent  1214  to allow ambient air into the interior of the reservoir  120 , but prevents fluid  122  in the reservoir  120  from leaking out of the vent  1214 . While a presently preferred embodiment of the reservoir  120  envisions the fluid  122  to be prepackaged in the reservoir  120 , those skilled in the art will recognize that the reservoir  120  may also be refillable, such as through the vent  1214 . 
     Alternatively, as shown in  FIG. 6 , an alternate embodiment of a reservoir  1218  may have a collapsible bladder  1220  that collapses under vacuum as the fluid  122  is drawn out of the reservoir  1218  during operation of the device  100 , without any air being able to enter the reservoir  122 . The bladder  1220  is preferably supple, biocompatible, and bondable. In the presently preferred embodiment, the bladder  1220  is constructed of aluminum film coated on both sides with a polymer resin. In the presently preferred embodiment, the bladder  1220  is approximately 0.025 to 0.10 mm thick. The bladder  1220  is attached to a rigid bladder neck  1221 . The neck  1221  prevents the bladder  1220  from contacting the proximal end  142  of the prime mover  140  as the bladder  120  collapses. Contact with the proximal end  142  would impede the function of the prime mover  140 . The bladder neck  1221  may be injection molded or extruded from a material that is rigid, biocompatible, and bondable. A material which meet these criteria includes polyethylene, although those skilled in the art will recognize that other, suitable, biocompatible materials may be used. The bladder  1220  and bladder neck  1221  are housed in a rigid reservoir housing  1222 . The housing  1222  is preferably injection molded from low cost polymer resins such as pvc, abs, or polypropylene. 
     An air vent  1223  in the housing  1222  allows the collapsible bladder  1220  to collapse as the fluid  122  is withdrawn from the reservoir  1218 , so that no adverse suction forces are generated during operation of the device  100 . The air entering the vent  1223  does not need to be filtered, since the bladder  1220  isolates the fluid  122  from the air. In this embodiment, no make-up air is required to enter the bladder  1220 . 
     Without limiting the type of fluids that could be contained in the reservoir  120 ,  1218  and dispensed by the present invention, diagnostic agents used by the medical professional that could be delivered with the present invention include mydriatics/cycloplegics, anesthetics, flourescein and flourescein/anesthetic combinations, and mydriatic reversal agents. Other agents which could be delivered with the present invention include over-the-counter agents, e.g., ophthalmic decongestants and lubricants, glaucoma medications (prestaglandins, beta blockers, alpha adrenergic agents, carbonic anhydrase inhibitors, miotics), and other ophthalmic medications. Optionally, several different therapeutic agents can be custom formulated in a single fluid to simplify adherence to multiple medication regimens. 
     Again, while an envisioned used for the device  100  of the present invention is directed toward ophthalmic use, those skilled in the art will recognize that the device  100  of the present invention may be used in other areas, such as respiratory treatment, and that other fluids, including respiratory medicaments, may be contained in the reservoir  120  instead. 
     Preferably, for photo-sensitive medicaments, the reservoir  120  may be tinted to prevent the transmission of certain deleterious wavelengths of light to the fluid  122  to prolong the useful life of the medicament in the reservoir  120 . The tint may be a dark brownish tint that is presently used for such medicaments in bottle/eye dropper form. 
     Optionally, as shown in  FIG. 2  the reservoir  120  may include a self-sealing valve  1224  in a distal wall  1226  of the reservoir  120 . The self-sealing valve  1224  allows the reservoir  120  to be inserted into the body  130 , and then removed from the body  130  without leaking fluid  122  from the reservoir  120 . 
     The self-sealing valve  1224  is preferably biased toward a closed position, such as by a helical spring (not shown). A seal, such as an o-ring  1228 , seals the valve  1224  against the wall  1226  of the reservoir  120  to eliminate fluid leakage from the reservoir  120  when the valve  1224  is in the closed position. A valve stem  1230  extends distally from the valve  1224 . When the reservoir  120  is inserted into the body  130 , the proximal end  142  of the prime mover  140  engages the valve stem  1230  and forces the valve stem  1230  into the reservoir  120 , opening the reservoir  120  into fluid communication with the prime mover  140 . 
     An alternative embodiment of a reservoir  1236  is shown in  FIGS. 7 and 8 . The reservoir  1236  is housed in a removable and replaceable cartridge  1237 . The reservoir  1236  incorporates a generally coiled tube  1238  that is sized to partially surround the proximal end  142  of the prime mover  140 . The tube  1238  may be constructed from polyethylene, although those skilled in the art will recognize that other suitable, biocompatible materials may be used. The tube  1238  preferably has a wall thickness in the range of approximately 0.1 to 0.3 mm thick, and an inside diameter in the range of approximately 1 to 5 mm. One end  1240  of the tube  1238  is fitted with a filter  1242  to allow makeup air to enter as the fluid  122  in the reservoir  1236  is drawn down. This filter  1242  is a biocompatible, gas-permeable membrane that is impermeable to liquid but permeable to air. One such material that may be used for the filter  1242  is tyvek.rtm. A distal end  1243  of the tube  1238  is sealed with a fluid impermeable seal  1244  that is broken by the distal end  142  of the prime mover  140  when the reservoir  1236  is connected to the device  100 , as shown in  FIG. 7 . 
     As the device  100  is operated and medication is consumed, the fluid  122  is drawn along the tube  1238 . The diameter of the tube  1238  is preferably specified in relation to the viscosity of the fluid  122  to insure that surface tension causes the fluid  122  to move in a column along the tube  1238 , i.e., no air is drawn in by the prime mover  140  until the fluid  122  is consumed. This design has the advantage of using nearly 100% of the medication loaded into the tube  1238 . This configuration has the further advantage of allowing the device  100  to operate in any orientation, even in zero gravity environments. Referring to  FIG. 7 , a clear window  1245  and a numerical scale  1246  on the side of the cartridge  1237  may indicate how many doses remain in the reservoir  1236 . The scale  1246  may be read with the device  100  in any orientation. 
     While a design of a reservoir  120  with a collapsible bladder  1220  and a design of a reservoir  1236  with a coiled tube  1238  are shown, those skilled in the art will recognize that other designs of reservoirs may be used. 
     Optionally, as shown in  FIG. 5 , a heater  1248  may be incorporated into the reservoir  120  to heat the fluid  122 . The heater  1248  is preferably either an inductance or a resistive heater that is electrically connected to a contact  1249  in the wall of the reservoir  120  that is electrically connectable to a contact (not shown) in the body  130  to provide electrical power to the heater  1248  to heat the fluid  122  in the reservoir  120 . However, for many ophthalmic medicines, heating the medicine is not desired, and those skilled in the art will recognize that the heater  1248  may be omitted in its entirety. 
     Also optionally, a low level sensor  1250 , shown in  FIG. 3 , may be incorporated into the reservoir  120  to indicate when the fluid  122  in the reservoir  120  is almost depleted. The sensor  1250  is electronically connected to the system controller  190  via electrical connection  1252  to provide an indication of fluid level in the reservoir  120 . The sensor  1250  may be electronically connected to an alarm, such as an optical or aural indicator, such as a blinking light or an audible alarm. 
     Body 
     Referring back to  FIG. 2 , the body  130  houses the prime mover  140  and provides a connection for the fluid reservoir  120  and for the nozzle assembly  150  to engage the prime mover  140 . The body  130  includes, at the distal end of the body  130 , a bushing  131  that is securely bonded to the body  130 , such as by an adhesive or a snap-fit. The bushing  131  includes at least one, an preferably, a plurality of bayonet clips  131   a  that are adapted to snap into the nozzle assembly  150  to retain the nozzle assembly  150  onto the body  130 . 
     The body  130  preferably includes a connection device, such as an orifice  132 , for attaching to the handle portion  160 . However, those skilled in the art will recognize that other connection methods, such as snap fit, bayonet clips, or other suitable mechanisms known to those skilled in the art may be used. Preferably, the body  130  connects to the top  162  of the handle portion  160  in only a single orientation so that electrical contacts in each of the body  130  and the handle portion  160  properly engage each other when the head portion  110  is connected to the handle portion  160 . 
     The body  130  also includes, at the proximal end of the body  130 , a collar spacer  133  that is fixedly connected to the body  130  to provide optimum spacing of the proximal end  142  of the prime mover  140  within the reservoir  120  to optimize the ability of the prime mover  140  to withdraw the fluid  122  from the reservoir  120  during operation of the device  100 . 
     The body  130  houses the prime mover  140 , and provides connection means for the reservoir  120 , the nozzle assembly  150 , and the handle portion  160 . The retainer  135  is fixedly connected to the body  130  and also releasably retains the reservoir  120  so that the reservoir  120  is removable from the remainder of the device  100 . As described above, the retainer  135  may include an engagement surface, or alternatively, other connection means, such as threaded connections, or other means known to those skilled in the art. 
     The body  130  includes a generally tubular passage  136  that is sized to accept the proximal end  142  of the prime mover  140 . A spacer recess  137  is disposed at the distal end of the body  130 , preferably below the passage  136 . The spacer recess  137  is used to releasably retain a targeting means, which will be described in detail later herein. 
     A seal  138  is disposed about the proximal end of the passage  136 . The seal  138  prevents any fluid  122  from leaking out of the reservoir  120  when the reservoir  120  is attached to the body  130 . In the present embodiment, the seal  138  is formed in the shape of a ring by injection molding or liquid injection molding using medical grade silicones or urethanes with durometers in the range of 5 to 30 shore a. 
     Preferably, the body  130  includes an activation indicator  1310  that is disposed on the top of the body  130 . The activation indicator  1310  may be a light, such as an led, that provides constant illumination as long as the activation switch  180  is depressed; a light that provides blinking illumination; a sound that provides audible indication, either by constant or by periodic beeping; some combination of these listed indicators, or some other indication that would indicate to the user that the device is ready for operation. The activation indicator  1310  operates when the activation switch  180  is initially depressed by the user. The activation indicator  1310  alerts the user that the device  100  is “on” and is about to spray the fluid  122  from the nozzle assembly  150 . The activation indicator  1310  is electronically connected to the system controller  190  via electrical leads (not shown). 
     The body  130  may be machined from solid metal or plastic stock, or may be injection molded with polymer resins such as abs, styrene, pvc, or other suitable material, as will be recognized by those skilled in the art. The body  130  may be injection molded or manufactured by other methods known by those skilled in the art. Preferably, the body  130  has a durometer within the range of approximately 90 to 100 shore a. 
     Prime Mover 
     Referring still to  FIG. 2 , as well as to  FIG. 9 , the prime mover  140  will now be described. The prime mover  140  is shown in  FIG. 2  in relation to the nozzle assembly  150  and the reservoir  120 . The prime mover  140  is preferably an ultrasonic oscillator formed by a piezoelectric assembly such as that found in the omron micro-air model ne-u03. The ne-u03 is a commercially available nebulizer that is typically used in nebulizers for bronchial therapy. However, the inventors of the present invention have discovered that this particular nebulizer is also suited for delivery of ophthalmic medicine to satisfy the needs that the present invention is intended to satisfy. The preferred piezoelectric assembly is described in detail in U.S. Pat. No. 6,651,650, the disclosure of which is incorporated herein by reference. However, those skilled in the art will recognize that the ne-u03 may be substituted for other piezoelectric assemblies, such as those discussed in the article nebulizers that use a vibrating mesh or plate with multiple aperatures to generate aerosol, by rajiv dhand md, respiratory care, December 2002, vol. 47, no. 12, which is also incorporated by reference herein. Alternatively, instead of using piezoelectric assemblies, those skilled in the art will recognize that other prime movers that are not piezoelectrically operated may be used. Examples of such other suitable prime movers include electric pumps, manual pumps, compressed gas, or other suitable prime movers, as will be recognized by those skilled in the art. 
     The prime mover  140  includes a proximal end  142 , a distal end  144 , and a central portion  146  disposed between the proximal end  142  and the distal end  144 . A longitudinal axis  148  extends along a length of the prime mover  140  between the proximal end  142  and the distal end  144 . A longitudinally extending lumen  1410  extends along the longitudinal axis  148  and extends the length of the prime mover  140 . Preferably, a perpendicular cross section of the lumen  1410  is generally circular in shape and has a diameter of approximately between 0.25 and 1.0 mm. However, those skilled in the art will recognize that the lumen  1410  may have other cross sectional shapes, such as a generally oblong, oval, or elongated shape. 
     The central portion  146  includes at least two generally annular piezoelectric elements  1412 ,  1414  that surround the lumen  1410 . The piezoelectric elements  1412 ,  1414  are electrically connected to the power source  170 , which drives the piezoelectric elements  1412 ,  1414  during operation of the device  100 . 
     Referring to  FIG. 2 , the prime mover  140  is retained within the body  130  by a distal seal  1426 . The distal seal  1426  is generally annular in shape and taper from a wider diameter to a smaller diameter from the piezoelectric elements  1412 ,  1414  toward the proximal end  142  and the distal end  144 , respectively. The distal seal  1426 , along with the seal  138 , restricts movement of the prime mover  140  within the body  130  and prevent fluid  122  that may leak through the device  100  from engaging the central portion  146  of the prime mover  140 . Preferably, the seal  1426  is constructed from a biocompatible material, such as medical grade silicon or urethane, although those skilled in the art will recognize that other suitable material may be used. 
     Referring back to  FIG. 3 , the proximal end  142  is immersed in the fluid  122  in the reservoir  120 . When the piezoelectric elements  1412 ,  1414  are excited, such as during operation of the device  100 , standing waves are formed which draw the fluid  122  into the proximal end  142  of the prime mover  140  and along the lumen  1410 . The standing waves propel the fluid  122  along the lumen  1410  to the distal end  144  of the prime mover  140  and to the nozzle assembly  150 , which is in mechanical contact with the distal end  144  of the prime mover  140 . As the prime mover  140  vibrates at ultrasonic frequencies, the prime mover  140  transfers a portion of its vibrational power to a mesh plate  156  in the nozzle assembly  150 , as will be described in more detail later herein. The fluid  122  that has been propelled along the lumen  1410  contacts the mesh plate  156 . The vibration of the plate  156  aerosolizes the fluid  122  and accelerates the fluid  122  away from the device  100  and toward the patient. 
     Nozzle Assembly 
     The nozzle assembly  150  is shown in an exploded perspective view in  FIG. 10 , as well as in an elevated sectional view in  FIG. 11 . The nozzle assembly  150  forms the mist that is discharged from the device  100  during operation. The nozzle assembly  150  includes, from a distal to a proximal direction, a cap  152 , a biasing member  154 , a mesh plate  156 , and a retainer  158 . 
     The cap  152  is generally annular, with a central opening  1510  disposed along the longitudinal axis  148 . Preferably, the body of the cap  152  extends in a distal direction and generally away from the longitudinal axis  148  to form a concave volume  1512  distal of the central opening  1510 . The concave volume  1512  reduces the likelihood that a foreign object, such as a user&#39;s finger, will touch the mesh plate  156 , potentially contaminating the plate  156 . 
     The cap  152  preferably includes a releasable lock feature, such as a female threaded connection (not shown) that releasably threadingly engages the retainer  158 , which has a mating twist lock feature, such as a mating male threaded connection (not shown). However, those skilled in the art will recognize that the cap  152  may engage with the retainer  158  by other means not shown, such as by snap engagement, bayonet means, or other suitable means known to those skilled in the art. 
     The mesh plate  156  is biased against the distal end  144  of the prime mover  140  by the biasing element  154 , such as a helical spring, that is disposed between the cap  152  and the mesh plate  156 . The biasing element  154  ensures that the mesh plate  156  is firmly engaged with the distal end  144  of the prime mover  140  to provide proper dispersion of the fluid  122  through the mesh plate  156  during operation of the device  100 . While a helical spring is preferred as the biasing element  154  because a helical spring provides a generally uniform biasing force around its perimeter, those skilled in the art will recognize that other types of biasing elements, such a leaf springs, may be used instead. As shown in  FIG. 11 , a clearance space  1518  is formed between the proximal side of the mesh plate  156  and the retainer  158  to allow the mesh plate  156  to vibrate during operation. 
     The mesh plate  156  is formed of a rigid material that is biocompatible and non-oxidizing, such as alumina ceramics, titanium allows, or stainless steel alloys. As shown in  FIG. 10 , an array of openings  1520  is formed in the mesh plate  156 . The number, density, size, and shape of the openings  1520  contribute to determining mist parameters such as volume, velocity, and droplet size distribution. The openings  1520  may be drilled by mechanical means, by fine jets of water, or by lasers. The preferred embodiment of the mesh plate  156  is constructed from a ceramic material and measures approximately 9 mm in diameter and 0.1 mm thick, having between 500 and 5000 openings  1520 . drilled by laser. The openings  1520  preferably have diameters in the range of approximately 0.5 to 30 microns. A mask (not shown) may be used that enables many openings  1520  to be drilled simultaneously. After each group of openings  1520  is drilled, the mask or the mesh plate  156  is indexed to a new position and the next set of openings  1520  is drilled. This step-and-repeat process continues until all the openings  1520  are made. 
     Enlarged cross sections of several embodiments of openings  1520   a ,  1520   b ,  1520   c ,  1520   d , and  1520   e  in mesh plates  156   a ,  156   b ,  156   c ,  156   d ,  156   e  are shown in  FIGS. 12   a ,  12   b ,  12   c ,  12   d ,  12   e . Referring to  FIG. 12   a , the mesh openings  1520   a  in the mesh plate  156   a  are preferably circular in cross section along a plane parallel to the longitudinal axis  148 , with an approximate hourglass cross section along a plane perpendicular to the longitudinal axis  148 . Referring to  FIG. 12   b , the mesh openings  1520   b  in the mesh plate  156   b  are wider at the proximal (bottom) end of the plate  156   b  and narrower at the distal (top) end of the plate  156   b . Referring to  FIG. 12   c , the mesh openings  1520   c  in the mesh plate  156   c  are narrower at the proximal (bottom) end of the plate  156   c  and wider at the distal (top) end of the plate  156   c . Referring to  FIG. 12   d , the mesh openings  1520   d  in the mesh plate  156   d  have a generally constant diameter between the proximal (bottom) end of the plate  156   d  and the distal (top) end of the plate  156   d.    
     The mesh plate may  156  incorporate one of several designs of openings  1520  as shown in  FIGS. 13   a  through  13   e . In the top plan view of the design shown in  FIG. 13   a , a mesh plate  156   e  is generally planar, with a plurality of openings  1520  in a generally circular pattern, with a center of the generally circular pattern along the longitudinal axis  148 . In the top plan view of the design shown in  FIG. 12   b , a mesh plate  156   f  is generally planar, with a plurality of openings  1520  in a generally elongated pattern, such as a rectangle or an oval. Alternatively, a mesh plate  156   g  may be generally convex, as shown in the side sectional view of the mesh plate  156   g  in  FIG. 13   c , to disperse the fluid  122  at a relatively wide angle to increase the field of dispersion of the fluid  122 . In yet another alternative, a mesh plate  156   h  may be concave, as shown in the side sectional view in  FIG. 13   d , to disperse the fluid  122  in a relatively small area. For each of the mesh plates  156   g ,  156   h  in  FIGS. 13   c  and  13   d , the pattern of openings may be circular, as shown in  FIG. 13   a , or elongated, as shown in  FIG. 13   b . The pattern of openings  1520  is aligned with the central opening  1510  in the cap  152  so that the fluid  122  that is dispersed through the mesh plate  156  passes through the central opening  1510  and forms a mist for deposition into the eye of the patient. 
     In an alternate embodiment, shown in  FIG. 13   e , a mesh plate  156   i  includes a generally flat plate with openings  1520   i  that are angled toward the longitudinal axis  148 . This design provides the benefits of an easy to produce mesh plate that directs the fluid to a focused point. 
     It is preferred that the openings  1520  in the mesh plate  156  generates mist particle sizes in the average range of between approximately 0.5 and 10 microns in diameter. It is also desired that the mist generated through the nozzle assembly  150  preferably extends about 7.5 to 10 cm in a mist plume diverging with a solid angle of approximately 10-20 degrees and traveling at a velocity of between approximately 4 and 30 cm per second, discharging approximately between 2 and 20 microliters per second, and preferably, between 7 and 10 microliters of fluid per second. 
     Referring back to  FIG. 11 , the retainer  158  preferably connects to the body  130  via the plurality of bayonet fittings  131   a  that snap into the retainer  158 , although those skilled in the art will recognize that other means for connecting the retainer  158  to the body  130 , such as by threaded connection, adhesive, or other suitable means, may be used. 
     The mesh plate  156  is removable from the remainder of the device  100  for cleaning, such as in an alcohol or other cleaning solution. To clean the mesh plate  156 , the retainer  158  is removed from the body  130 , releasing the cap  152 , the biasing element  154 , the mesh plate  156 , and the retainer  158  from the remainder of the device  100 . The biasing element  154  biases the mesh plate  154  against the retainer  158 , keeping the nozzle assembly  150  intact. After cleaning, the nozzle assembly  150  is reconnected to the remainder of the device  150 . The distal end  144  of the prime mover  140  engages the mesh plate  156 , forcing the mesh plate  156  away from the retainer  158  so that the mesh plate  156  may be able to vibrate when excited by the prime mover  140 . 
     Optionally, as shown in  FIGS. 2 and 11 , an overcap  1522  may be disposed over the distal end of the cap  152  to keep the mesh plate  156  clean between uses. The cap  152  may include a peripherally spaced groove  1523  that is engageable with a corresponding protuberance  1523   a  for a snap fit connection that securely retains the overcap  1522  onto the cap  152 , yet allows the overcap  1522  to be removed from the cap  152  with a minimum of effort. Alternatively, the overcap  1522  may attach to the cap  152  with a snap action, a thread, a bayonet, or other simple fastening means. The overcap  1522  may be machined from solid metal or plastic stock, or may be injection molded with polymer resins such as abs, styrene, or pvc. The overcap  1522  may optionally be tethered to the device  100  with a lanyard made of wire cable or plastic filament. Alternatively, the overcap  1522  may be attached to the nozzle assembly  150  with a hinge (not shown). The hinge may incorporate a spring or other biasing member that automatically retracts the overcap  1522  away from the distal end of the cap  152  when a latch is released. 
     Dosage Adjustment 
     Different medications and/or ophthalmic treatment regimens may require different amounts of a medication to be administered with each use of the device  100 . Alternatively, a larger patient may need a larger dose of a medication than a smaller patient. Therefore, an ability to adjust dosage amount may be required. The device  100  may optionally be equipped with user-accessible adjustments for flow rate (mist volume) and total flow (dose). These adjustments may be electromechanical (knobs or wheels operating potentiometers), or electronic (buttons or keys providing digital data to the system controller  190 ). 
     In one embodiment of a dosage adjustment, a dosage adjuster  1530 ,  1530   a  may be disposed on the nozzle assembly  150 , such as is shown in  FIGS. 14 and 15   a - 15   b . The dosage adjuster  1530  includes a potentiometer  1532  rotatably connected to the cap  152 . The potentiometer  1532  may include an infinitely positionable pot that is movable across a resistive film  1536 , as shown in  FIG. 15   a , or a discretely positionable pot that is movable across a resistive film  1538  as shown in  FIG. 15   b . For either film  1536 ,  1538 , rotation of the potentiometer  1532  changes the resistance of the potentiometer circuit, as is well known to those skilled in the art. The change in resistance changes a dosage voltage signal that is transmitted to the system controller  190  via a circuit (not shown). The system controller  190  interprets the voltage signal received and in turn transmits an operation duration signal to the prime mover  140 , which controls the amount of time that the prime mover  140  operates when the activation switch  180  is engaged, thereby controlling the amount of fluid  122  that is discharged from the device  100 . 
     While the dosage adjuster  1530  may be disposed on the nozzle assembly  150  as shown, those skilled in the art will recognize that a dosage adjuster  1530   a  may be disposed on the handle portion  160 , as is alternately shown in  FIG. 15   c . The dosage adjuster  1530   a  preferably operates similarly to the dosage adjuster  1530  described above. Preferably, the dosage adjuster  1530   a  is disposed in an inconvenient location, such as behind a panel (not shown). It is typically not desirable to be able to easily adjust the dosage adjuster  1530   a  so that the user does not accidentally adjust the dosage while picking up or holding the device  100 . The flow rate of fluid  122  dispensed as a mist from the device  100  is preferably adjustable between about 10 to 100 microliters/sec. 
     In order to ensure that dosing is consistent, the location of the nozzle assembly  150  relative to the eye during dispensing of medication may also need to be controlled. Various targeting mechanisms have been developed for this purpose. Referring back to  FIG. 14 , a first embodiment of a targeting mechanism  1540  may be incorporated into the nozzle assembly  150 . The targeting mechanism  1540  is used to provide the user with an optimum distance to space the nozzle assembly  150  from the patient&#39;s eye to maximize effectiveness of the device  100 . The targeting mechanism  1540  includes two projection lenses  1542 ,  1544  that are disposed on the nozzle assembly  150 , preferably spaced 180 degrees from each other on either side of the longitudinal axis  148 . The lenses  1542 ,  1544  are angled toward the longitudinal axis  148  such that projections from the lenses  1542 ,  1544  intersect at the longitudinal axis  148  at an optimum distance for spacing the nozzle assembly  150  from the Patient&#39;s eye, as shown in  FIG. 16 . A light source  1546 ,  1548  is disposed proximal of each lens  1542 ,  1544 , respectively, with each light source  1546 ,  1548  being directed along the projection line of each respective lens  1542 ,  1544 . The light sources  1546 ,  1548  may be leds, incandescent sources, lasers, or other suitable light source, as will be recognized by those skilled in the art. The light sources  1546 ,  1548  are electrically connected to the activation switch  180  so that the light sources  1546 ,  1548  activate upon initial engagement of the activation switch  180 . 
     Preferably, the light sources  1546 ,  1548  and the lenses  1542 ,  1544  form a pattern on the target eye when the device  100  is aimed at the eye and the activation switch  180  is depressed. The pattern may be formed by separate masks  1550 ,  1552  that are disposed between each light source  1546 ,  1548  and its respective lens  1542 ,  1544 , as shown in  FIG. 16 , or, alternatively, the mask may be formed on each lens  1542 ,  544  (not shown). In either embodiment, the targeting mechanism  1540  forms one of three general patterns on the iris or the sclera of the eye. When the device  100  is too far from the eye, a pattern similar to a pattern formed in one of  FIGS. 17   a ,  18   a ,  19   a ,  20   a ,  21   a  is formed. When the device  100  is a correct distance from the eye, a pattern similar to the pattern formed in one of  FIGS. 17   b ,  18   b ,  19   b ,  20   b ,  21   b  is formed. When the device  100  is too close to the eye, a pattern similar to the pattern formed in one of  FIGS. 17   c ,  18   c ,  19   c ,  20   c ,  21   c  is formed. Those skilled in the art will recognize that the patterns shown in  FIGS. 17   a - 21   c  are exemplary only, and that numerous other patterns may be formed. 
     In addition to assisting in determining the optimum distance for spacing the device  100  from the eye, the targeting mechanism  1540  also aids in accurately aiming the device  100  at the eye, so that the mist generated by the device  100  is directed toward the middle of the eye, and not off to the side. 
     While the targeting mechanism  1540  described above is useful for a professional practitioner to use to aim the device  100  at a patient, those skilled in the art will recognize that an alternative embodiment of a targeting mechanism (not shown) may be used to by a patient on himself/herself by directing the targeting mechanism onto his/her retina. 
     Handle Portion 
     Referring back to  FIGS. 1 and 2 , the handle portion  160  contains the bulk of the electronics, as well as the activation switch  180  and the power supply  170 . As described previously above, the handle portion  160  may also include a dosage adjuster  1530   a  (shown in  FIG. 15   c ) for adjusting the amount of fluid  122  that is discharged per use. The handle portion  160  includes an elongated body  162  having a top end  164 , which is connected to the body portion  130 , as well as a bottom end  165 , which is configured for removable insertion into a base  166 . 
     In a non-use operation, the device  100  is preferably disposed in the base  166 , as shown in  FIGS. 1 and 2 . The base  166  typically rests on a desktop and holds the device  100  such that the device  100  can simply be lifted from the receiver for use. The base  166  includes a cavity  167  that is sized and shaped to securely receive the bottom end  165  of the handle portion  160 . The base  166  may also be weighted to keep the device  100  from toppling over after the device  100  is inserted into the base  166 . Alternately, the base  166  may include an adhesion device, such as a suction cup or an adhesive (not shown), to keep the device  100  from toppling over. 
     Preferably, the handle portion  160  and the base  166  may be separately machined from solid metal or plastic stock, or may be injection molded with impact resistant polymer resins, such as abs, polycarbonate, pvc, or other suitable material, as will be recognized by those skilled in the art. The handle portion  160  may optionally include a rubberized grip  168 , at least along a length of the handle portion  160  facing the distal end of the device  100 . The rubberized grip  168  is softer for the user and helps prevent the user from accidentally dropping the device  100 . The grip  168  may also include indentations for a user&#39;s fingers to enhance ergonomics. The grip  168  may be manufactured from a material having a hardness in the range of 10-50 shore a that may be molded separately and bonded onto the handle portion  160 . 
     Referring now to  FIGS. 22   a  and  22   b , an optional mechanical targeting means  1620 , for setting an optimum distance between the nozzle assembly  150  and the patient&#39;s eye, is shown. In lieu of the electronic targeting means  1540  shown and described with respect to  FIGS. 14 and 17   a - 21   c , the targeting means  1620  may be mechanically incorporated into the device  100 . 
     The targeting means  1620  includes a generally elongated member  1622  that includes a connected end  1624  that is releasably inserted into the spacer recess  137 , and a free end  1628  that is disposed away from the connected end  1624 . As shown in  FIG. 22   b , the free end  1628  is generally “tee-shaped” and is preferably formed in the shape of an eyelid depressor to depress the tear sac under the eye and to provide a larger ocular surface area for contact with the fluid  122  being dispensed from the device  100 . Since the free end  1628  engages the patient and the patient&#39;s eye area, it is preferred that the targeting means  1620  is disposable between uses to avoid any contamination from one patient to the next. 
     Preferably, the elongated member  1622  is constructed from impact resistant polymer resins, such as abs, polycarbonate, pvc, or some other suitable rigid material to minimize deflection of the elongated member  1622  during operation. Also preferably, the free end  1628  is either coated with or constructed from a soft material, such as rubber in order to reduce the likelihood of eye injury in the event that the free end  1628  accidentally engages the eye. 
     Power 
     A preferred power source  170  for the device  100  is battery power. As can be seen in  FIGS. 1 and 2 , a battery  172  is removably inserted into the bottom end  165  of the handle portion  160 . A cover  169  retains the battery  172  in the handle portion  160 . The cover  169  is removable so that the battery  172  may be easily replaced. The cover  169  may be releasably connected to the handle portion  160  by clips, threaded fasteners, or other means known to those skilled in the art. 
     The battery  172  may be a single-use lithium ion or alkaline type, or the battery  172  may be rechargeable lithium-ion, nickel-cadmium, nickel-metal-hydride, or other battery type. The battery  172  may be a single battery or a plurality of batteries electrically connected in series. For example, two lithium photo batteries neda/ansi type cr2 (e.g. Duracell ultra cr2 li/mno2) may be connected in series will be used to power the device  100 . The batteries  172  are preferably rated for 3 v and approximately 2000 mah. The batteries  172  are connected in series to provide a total capacity 2000 mah at 6 v. The batteries  172  preferably have a peak current rating of at least 1.8 a. 
     If a rechargeable battery is used, a charger is required. Those skilled in the art will recognize that the charger may be integrated into the device  100  or enclosed in a separate enclosure, such as in the base  166 . The base  166  includes a standard 110 v electrical cable  1610  extending therefrom that is electrically connected to an ac/dc converter (not shown) in the base  166  that converts 110 v ac supply to 6 v dc. The base  166  also includes a pair of contacts (not shown) that engage recharger contacts (not shown) in the bottom end  165  of the handle portion  160  when the device  100  is inserted into the base  166 . 
     Alternatively, the device  100  may be designed such that the battery  172  can be easily removed from the device  100  and charged in a separate charger (not shown). A further alternative is to replace the battery with an ac-to-dc converter, and power the device  100  through a line cord connected to an ac source. 
     Activation Switch 
     An activation switch  180  extends through the handle portion  160  to activate the device  100  upon a user engaging the activation switch  180 . The activation switch  180  is preferably a button, as is shown in  FIG. 2 , or some other suitable device, such as a trigger, as will be recognized by those skilled in the art. Alternatively, the activation switch may be a foot switch (not shown) that is electronically connected to the system controller  190  to activate the device  100 , such as by an electrical line. 
     The activation switch  180  is electronically connected to the system controller  190  via leads  182 ,  184 . Preferably, the activation switch  180  is a three-position switch such that, when the activation switch  180  is depressed an initial amount from an open position to an initially closed position, the device  100  is activated. This activation illuminates the activation indicator  1310  to indicate that the device  100  is about to operate. When the activation switch  180  is completely depressed, the activation switch  180  transmits a signal, through the system controller  190 , to operate the prime mover  140  for a period of time determined, through the system controller  190 , by the settings on the dosage adjuster  1530 . Preferably, the time period for operation extends between approximately 0.5 and 5 seconds. However, operation time of the prime mover  140  is not dependent on the duration of time that the activation switch  180  is depressed, but on the settings of the dosage adjuster  1530 . However, it is preferred that, if the activation switch  180  is depressed for an extended period of time, such as greater than two seconds, the system controller  190  interprets the signal received from the activation switch  180  as a signal to run the device  100  continuously for a predetermined, extended period of time, such as thirty (30) seconds, such as to run a cleaning solution such as saline, through the device  100  to clean the device  100 . Alternatively, if the activation switch  180  is depressed for longer than the predetermined period of time, the system controller  190  will provide power for the prime mover  140  to operate as long as the activation switch  180  is fully depressed. 
     Electronics 
     The primary function of the system controller  190  is to energize the prime mover  140 , which is preferably a piezoelectric transducer assembly or other piezo device, as described above. When energized, the prime mover  140  generates a mist of fluid droplets from the fluid  122 . The energizing signal for the prime mover  140  must excite the prime mover  140  at the proper resonant frequency, and must supply enough energy to the prime mover  140  to cause misting. A simple user interface, such as the activation switch  180 , is required for operation and control of the prime mover  140 . A microprocessor  192  will be used to provide intelligence for the interface between the activation switch  180  and the prime mover  140 , and to supervise the circuits driving the prime mover  140 , as well as all of the electronic features. 
     The system controller  190  controls operation of the device  100  and includes a microprocessor  192 , preferably in the form of a pcba (printed circuit board assembly), to incorporate of the electronics for operation of the device  100 .  FIG. 23  shows an electronic block diagram for a preferred embodiment of the system controller  190 . The microprocessor  192  is housed in the system controller  190 , through which a majority of the operation of the device  100  passes. The system controller  190  preferably also contains a non-volatile memory, input/output (“i/o”) devices, digital-to-analog (“d/a”) and analog-to-digital (“a/d”) converters, driver circuits, firmware, and other electronic components, as will be described in detail herein. Alternatively, those skilled in the art will recognize that simple logic components may be used. 
     The activation switch  180  is part of a normally open (“no”) circuit that includes the activation indicator  1310 . As described above, the activation switch  180  is a three-position switch, with the first position in the no condition. The second position, when the activation switch  180  is depressed part way, powers the activation indicator  1310  to indicate to the user that the device  100  is on. The third position, when the activation switch  180  is fully depressed, activates the device  100  to operate the prime mover  140  to generate a mist from the nozzle assembly  150  for medication dispensing to the patient. To conserve power and lengthen operational battery life, all circuits are disconnected from power while the activation switch  180  is open. 
     A power management &amp; low battery indicator  194  includes an electronic circuit that automatically measures the battery voltage and provides a visual or audible (beeping) indication if the voltage has dropped below a preset level. Power management chips (also known as “gas gages”) are commercially available for various battery types, or such a circuit may be constructed from discrete components. Preferably, the circuit also provides “sleep” or “hibernate” modes, as are known to those skilled in the art, in which battery life is extended by reducing power consumption when the device  100  has been inactive for a preset amount of time. 
     An optional power conditioning circuit  196  provides a constant and regulated voltage to the rest of the system controller  190 . Power conditioning chips are commercially available for various voltage and current requirements, or alternatively, such a circuit may be constructed from discrete components. 
     A voltage step-up &amp; driver (vsd) circuit  198  powers the prime mover  140 . For a prime mover  140  that includes the piezo device described above, the purpose of the vsd circuit  198  is to drive the piezoelectric crystal contained in the piezo device at a desired resonant frequency. Different crystals and piezoelectric assemblies have different resonant frequencies, as well as different q-factors, so the vsd circuit  198  is preferably custom designed to match the operating characteristics of the particular piezo device. The vsd circuit  198  contains an oscillator formed of integrated and/or discrete components such as power transistors, power diodes, capacitors, and coils. 
     Preferably, the piezo device is driven by a square wave at its resonant frequency in the range of 50 khz to 70 khz. Since each piezo device has a slightly different resonant frequency, the circuit will use a phase lock loop (pll) or other feedback technique with a voltage controlled oscillator (vco) to lock on to the piezo resonant frequency and to automatically adjust the drive signal frequency as the resonant frequency varies. The piezo device is preferably driven by a peak-to-peak signal in the range of 200 v, or as appropriate to provide sufficient misting. Using the preferred omron piezoelectric device described above, the mist volume produced with this method is in the range of approximately 10 to 100 microliters/second. 
     The system controller  190  also optionally includes a heater control  1910  and that is electronically connected to the optional reservoir heater  1248  to heat the fluid  122  in the reservoir  120 , as desired. The heater control  1910  includes a feedback loop to control the desired temperature of the fluid  122  in the reservoir  120 . A heater power supply  1912  is also electronically connected to the system controller  190  to provide a power supply to the optional heater  1248 . 
     Low Fluid Level 
     If the device  100  includes the low level sensor  1250  in the reservoir  120  as described above, the device  100  also includes a low fluid level alarm  1914  that is set to alarm when the fluid  122  in the reservoir  120  is depleted to a predetermined level. The low reservoir sensor  1250  is programmed to transmit a signal to the system controller  190  when the fluid level reaches the predetermined level. The system controller  190  in turn transmits a signal to the alarm  1914 . The alarm  1914  may be a visual alarm, such as a blinking light, or the alarm  1914  may be an audible alarm, such as a beep. 
     Dosage Adjustment 
     A manual method and apparatus for adjusting dosage amount dispensed during operation of the device  100 , using the dosage adjuster  1530 ,  1530   a  has been previously described. Adjustment of the dosage adjuster  1530 ,  1530   a  transmits a signal to a dose control circuit  1916  to determine the length of time that the prime mover  140  operates to dispense the fluid  122  from the reservoir  120  to the patient. The system controller  190  also includes a flow volume control circuit  1918  that determines the volume of the fluid  122  per unit time that is dispensed through the prime mover  140 . The total amount of the fluid  122  dispensed is determined by the value of the flow rate as determined by the flow volume control circuit  1918  times the length of time of operation of the prime mover  140  as determined by the dose control circuit  1916 . Preferably, the flow volume control circuit  1918  is preprogrammed into the system controller  190 , while the dose control circuit  1916  may be manually adjusted based on the type of medication and the dosage that the prescribing physician determines is necessary based on the patient&#39;s condition. 
     Alternatively, instead of manually adjusting the dosage amount, the dosage amount may be adjusted electronically, such as by external calibration of the system controller  190  to adjust operational values of the dose control circuit  1916  and the flow volume control circuit  1918  based on need. 
     Dosage Complete Indicator 
     The system controller  190  also includes a “dosage complete” indicator  1920  that indicates when the device  100  has dispensed the prescribed amount of fluid  122  from the reservoir  120 . The indicator  1920  may be may be a visual alarm, such as a blinking light, or the indicator  1920  may be an audible alarm, such as a beep. The indicator  1920  preferably is activated after a slight time delay, such as approximately 0.5 second, after the device  100  ceases to dispense the fluid  122  from the nozzle assembly  150 . This delay ensures that the user does not remove the device  100  from in front of the patient&#39;s eye until all of the prescribed dose of medication has been dispensed from the device  100 . Since the system controller  190  controls operation of the prime move  140 , the system controller  190  is able to calculate the desired delay time between stopping operation of the prime mover  140  and sending the signal to the indicator  1920  to indicate that the dosage is complete. 
     Targeting Optics 
     If the optional electronic targeting mechanism  1540  is used, depressing the activation switch  180  to the first position transmits a signal to the system controller  190  to activate the targeting mechanism  1540 , illuminating the light sources  1546 ,  1548  to project images on the patient&#39;s eye. The targeting mechanism  1540  remains activated when the activation switch  180  is depressed to the second position. When the activation switch  180  is released, signal to the system controller  190  ceases, and the targeting mechanism  1540  is deactivated by the system controller  190 . 
     Outside Communications 
     Optionally, the device  100  may include an input/output (i/o) device  1922  for transmitting information between the device  100  and an outside device, such as a personal computer, pda, or other such electronic device that is capable of displaying information transmitted from the device  100 . Information that may be transmitted from the device  100  includes, but is not limited to, usage information, such as the number of times the device  100  was used, and at what times; dosage amount per application; and current and voltage draw of the device  100  during use, as well as other operational information about the device  100 . Further, information may be transmitted from the outside device to the device  100 . Such information may include, but is not limited to, clearance information to clear the system controller  190  memory of previous information that has already been downloaded to the outside device; operational information that allows the device  100  to be used with particular medicament reservoirs; temperature settings for the heater control  1910 ; and operational duration information to adjust the dose control circuit  1916  and the flow volume control circuit  1918  to adjust dosage amounts, as well as other information that may be transmitted to the system controller  190 . 
     As shown in  FIG. 2 , the  100  device  1922  may include a port  1612  on the handle portion  160  for physically connecting the device  190  to the outside device, such as by a cable. The port  1612  may be a standard universal serial bus (usb) port, or some other suitable port as will be recognized by those skilled in the art. The port  1612  is electronically connected to the system controller  190  by a port cable  1614  that transmits information between the port  1612  and the system controller  190 . Alternatively, the i/o device  1922  may include an infrared transmitter/receiver (not shown) that allows the device  100  to be placed near, but not physically connected to, the outside device to exchange information such as the information described above. 
     A pediatric version of a device  200  according to an alternate embodiment of the present invention, shown in  FIG. 24 , may include a facade  204  at the distal end  202  of the device  200  that encourages younger patients to look in the direction of the device  200 . For example, for ophthalmic delivery, the facade  204  may include a clown face or an animal face that catches the attention of the patient and distracts the patient from the medicament that is being dispensed from the device  200 . In the embodiment shown in  FIG. 24 , the nose of the facade is the mesh plate  156 . Alternatively, the facade  204  may include moving parts to distract the patient during operation of the device  200 . 
     Alternatively, a veterinary version of a device  300  according to yet another alternate embodiment of the present invention, shown in  FIG. 25 , may include a facade  304  at the distal end  302  of the device  300  that distracts the animal that is being medicated. The facade  304  may include a moving element for the animal to focus upon during administration of the medicament. 
     The embodiments shown and described above may be offered in a reusable configuration. In this event, the parts may be injection molding from clear polymer resins that withstand repeated sterilization by steam autoclave, such as autoclaveable versions of acrylics, styrenes, and polycarbonates. 
     Alternatively, the embodiments shown may be offered as a sterile disposable. In this case it may be injection molded from a wide variety of clear polymer resins, including acrylics, styrenes, urethanes, pmma, and polycarbonates. These resins are generally compatible with industrial sterilization by e-beam, gamma, and eto. 
     Use 
     Between uses, the device  110  is typically stored in the base  166 , with the bottom end  165  of the handle portion  160  inserted into the cavity  167  in the base  166 . The electrical cable  1610  is connected to an external power supply to provide electrical power to the batteries  172  to charge/recharge the batteries  172 . The heater  1248 , if used, heats the fluid  122  in the reservoir. The temperature of the fluid  122  is controlled by the heater controller  1910  to maintain the fluid  122  at a desired temperature. 
     The device  100  is designed so that it can be used by one person to self administer medicament, such as a patient in his/her home, or, the device  100  can be used by one person to administer medicament to a second person, such as a medical professional treating a patient in a medical office or a hospital setting. 
     For self use, the user removes the device  100  from the base  160  and aims the discharge end of the nozzle assembly  150  toward the eye into which the user intends to insert the eye medication. If the optional mechanical targeting means  1620  is connected to the device  100 , the user inserts the connected end  1624  into the spacer recess  137 . The user then uses the free end  1628  of the targeting means  1620  to depress the eyelid. When the device  100  is in the desired position, the user then uses his/her thumb, as shown in  FIG. 26 , to depress the activation switch  180 . By pressing the activation switch  180  to the first position, the activation indicator  1310  is illuminated, indicating that the device  100  is ready for operation. 
     For professional use on a patient, the user, such as an optometrist or an ophthalmologist, removes the device  100  from the base  160  and aims the discharge end of the nozzle assembly  150  toward the eye into which the user intends to insert the eye medication. If the optional mechanical targeting means  1620  is connected to the device  100 , the user inserts the connected end  1624  into the spacer recess  137 . The user then uses the free end  1628  of the targeting means  1620  to depress the eyelid. When the device  100  is in the desired position, the user then uses his/her index finger, as shown in  FIG. 27  to depress the activation switch  180 . By pressing the activation switch  180  to the first position, the activation indicator  1310  is illuminated, indicating that the device  100  is ready for operation. 
     If the optical targeting mechanism  1540  is used, the user aims the device  100  generally toward the patient&#39;s eye and, using his/her forefinger, as shown in  FIG. 27 , depresses the activation switch  180  to the first position. The activation indicator  1310  is illuminated, indicating that the device  100  is ready for operation. Also, the light sources  1546 ,  14538  on the targeting mechanism  1540  are illuminated, projecting images onto the patient&#39;s eye. Preferably, the images are any of the images shown in  FIGS. 17   a - 21   c . The user can adjust the distance and aim of the device  100  relative to the patient&#39;s eye based on the images projected onto the patient&#39;s eye. 
     The remainder of the description of the operation of the device  100  is the same whether the device  100  is being used for self-administration of medication or whether the device  100  is being used by a professional to administer medication to a patient. 
     The user presses the activation switch  180  to the second position and then releases the activation switch  180 , transmitting a signal to the system controller  190  to operate the prime mover  140 . An electronic operational signal is transmitted through the power management circuit  194  and the vsd circuit  198  to the prime mover  140  which, in the case of the piezoelectric device described above, causes the piezoelectric device to vibrate, preferably at an ultrasonic frequency, along its longitudinal axis  148 . The prime mover  140  is operated for a predetermined amount of time, preferably between approximately 0.5 and 2 seconds, as programmed into the system controller  190  prior to use. The prime mover  140  operates for the predetermined amount of time, regardless of how long the activation switch  180  is depressed, unless the activation switch  180  is depressed in excess of a predetermined period of time, such as 5 seconds, as will be described in more detail later herein. 
     The vibration of the prime mover  140  draws fluid  122  from the reservoir  120  and through the lumen  1410 . The fluid  122  exits the distal end  144  of the prime mover  140  and passes through the openings  1520  in the mesh plate  156 , where the fluid  122  is broken into micron-sized particles, which are directed toward the patient&#39;s eye. After the prime mover  140  has operated for the predetermined period of time, the system controller  190  ceases to transmit the operational signal and the prime mover  140  stops. At this time, the system controller  190  transmits a signal to the dose complete indicator  1920  to indicate to the user that the dosage is complete. 
     If the user is using the mechanical targeting means  1620 , the user preferably removes the connected end  1624  from the spacer recess  137  and discards the elongated member  1622  to ensure that any bacteria from the patient&#39;s eye is not transmitted to the targeting means  1620  and then retransmitted to the next patient. 
     If the level of the fluid  122  in the reservoir  120  drops below a predetermined level, the low reservoir sensor  1250  transmits a signal to the system controller  190 , which in turn transmits a signal to the low reservoir indicator  1914 , informing the user that the reservoir  120  must be removed and a new reservoir must be inserted into the body  130 . 
     If the low battery indicator  194  indicates that the power source  170  is at lower power, the user may insert the device  100  into the base  166  to charge the power source  170 , or alternatively, replace the power source  170 . 
     In the event that the user desires to change medication in the reservoir  120 , it is recommended that the device  100  be “flushed” after removing the original medication but before using the new medication, so as not to contaminate the new medication with the old medication. In such an instance, the user inserts a reservoir containing a cleaning fluid, such as a saline solution into the body  130 , and depresses the activation switch  180  in excess of a predetermined period of time, such as 5 seconds. The system controller  190  recognizes the extended depression of the activation switch  180  as the start of a cleaning cycle and operates the prime mover  140  for an extended period of time, such as for 30 seconds, or some other predetermined time, as desired. At the end of the cleaning cycle, the dose complete indicator  1920  may activate, alerting the user that the device  100  is clean, and that a new medication may now be used in the device  100 . 
     While the embodiments of the present invention described above are preferably used to deliver medicament to a patient&#39;s eye, those skilled in the art will recognize that the embodiments of the present invention may be used with a respiratory medication instead of an ophthalmic medication, and that the invention may be used in the treatment of respiratory ailments instead of ophthalmic ailments. 
     It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.