TECHNICAL FIELD

The present disclosure relates to techniques for dispensing fluid into a subject’s eye, and more specifically to a device and method for dispensing a controlled amount of fluid into a subject’s eye upon detection of the eye being in an open state.

BACKGROUND

The main treatment for many eye conditions such as glaucoma and dry eye is eye drop application and a large proportion of these patients are of an advanced age where manual dexterity and muscle strength is reduced. Even in younger age groups and particularly children, this process is notoriously challenging.

This universal challenge is exemplified by a study of elderly patients who had eye drops prescribed, who completed a questionnaire and demonstrated their eye drop application technique. Examining the eye drop application of 43 consecutive outpatient attendees, aged over 75 years, it was identified that less than one-third of patients applied drops themselves, with the remainder relying on others. Notably, one-third of this group lived alone without access to support for daily eye drop application. It was estimated that half of those who usually applied their own treatment were unlikely to succeed in instilling a drop into the conjunctival sac - the anatomical region where drops should be instilled for sufficient dosing. Currently, it is not common practice in the healthcare sector for patients to be prescribed aids or appliances to improve their eye drop application technique.

Furthermore, the compliance of eye drops is poor especially if more than one drop is prescribed, exacerbated in patients unable to instil eye drops. This can be due to physical limitations, including tremors, arthritis, and limited mobility, or cognitive issues, including Alzheimer’s or simply forgetfulness.

To monitor adherence, the current paradigm uses electronic health records (EHRs) to monitor pharmacy refills and repeat prescriptions. However, the accessibility of such EHRs across the healthcare sector can be limited. Finally, current aids for dispensing eye drops are unable to monitor dosing and medication adherence through longitudinal data capture and storage of images of the patient’s eye. There do exist devices that are able to provide some degree of assistance and/or automation in the dispensing of eye drops. For example, some devices have been considered which assist with positioning the eye drop delivery device in line with the eye. Additionally, some devices are envisaged that are equipped with automated eye drop delivery / dispensing mechanisms which are triggered / controlled based upon the detection of whether the subject’s eye is open (for example, as envisaged in US 2012/286634 A1). However, the lack of flexibility of such automated mechanisms, especially when considering their integration and use in combination with existing eye drop medication bottles, means that their use is practically limited in the healthcare sector.

It is against this background, and with the aim of overcoming at least some of the disadvantages set out above, that the present disclosure has been devised.

SUMMARY OF THE DISCLOSURE

According to an aspect of the disclosure, there is provided a fluid dispensing device for automated delivery of fluid to an eye of a subject. The device comprises a housing configured to accommodate a reservoir containing the fluid for delivery and a fluid delivery mechanism configured to apply controllable pressure to the fluid in the reservoir to cause a predefined amount of the fluid (e.g., one or more drops of the fluid, or droplets if dispensed as a spray) to be dispensed from the reservoir to the subject’s eye. The device also comprises a sensor unit, in operative communication with the fluid delivery mechanism, the sensor unit being configured to monitor the subject’s eye and to detect whether the subject’s eye meets a predetermined condition for fluid dispensing to be carried out. The sensor unit is configured, upon detection of the predetermined condition being met, to cause the fluid delivery mechanism to apply the controllable pressure.

This application of controllable pressure can be carried out directly to the fluid in the reservoir (e.g., via the application of suction force or negative pressure to the fluid); or indirectly via the application of pressure to a portion of the reservoir, which translates to a reduction in internal space within the reservoir and hence thereby to the fluid.

Advantageously, the above-described device configuration enables automated delivery of fluid (for example, eye drops or spray) to the eye of the subject based on detection of a predetermined condition associated with the subject’s eye. This reduces the level of effort / input that is required by the operator of the device (who would usually be the subject themselves), whilst nevertheless maintaining the ability to deliver a (precisely) controllable amount of fluid to the subject’s eye at an appropriate time. The combination of automated detection of an appropriate time at which to dispense the fluid to the subject’s eye, as well as an automated, easily controllable and repeatable mechanism for effecting such dispensing, enables successful drop dispensing to take place regardless of the subject’s / operator’s capabilities or skill (for example, the steadiness of their hands), and thereby increases the successful drop instillation rate. It will be appreciated that different sizes and shapes of reservoir may potentially be accommodated by the housing, which provides an increased degree of flexibility for the device.

The sensor unit may comprise an image capture device configured to capture one or more images (e.g., a plurality of images) of at least a portion of the subject’s eye; and a processing unit configured to analyse the captured images to determine whether the subject’s eye meets the predetermined condition. Advantageously, monitoring of the subject’s eye in this manner allows substantively real-time image capture of the subject’s eye and hence an increase in the relative ease with which it can be determined that the subject’s eye meets a predetermined condition. In such cases, computer vision software can be utilised to identify / detect various features of the subject’s eye that may be visible in the captured images.

For example, in some embodiments, the predetermined condition relates to an eye state of the subject, and the detected predetermined condition for fluid dispensing to be carried out corresponds to the subject’s eye state being in an ‘open state’. Image capture and analysis of the subject’s eye is particularly suitable for scenarios where an eye state of the subject’s eye (e.g., open or closed) constitutes the predetermined condition for initiating fluid dispensing, as such states can be relatively easily ascertained from the captured images. Utilising the ‘open state’ as the predetermined condition for fluid dispensing is also advantageous as it ensures that fluid dispensing is primarily (or only) carried out when the instillation of the drop is likely to be successful - i.e. , when the subject’s eye is (sufficiently) open to allow the drops to enter the eye.

In some instances, the processing unit may be configured to determine the eye state of the subject utilising a machine learning model trained using a plurality of previously obtained images of eyes exhibiting a variety of states ranging from the ‘open state’ to a ‘closed state’. Advantageously, this provides a relatively easily implementable method for automating eye state detection, which can nevertheless be flexible to accommodate many different characteristics of the subject’s eye whilst still (after training) accurately detecting the appropriate predetermined condition that is used to trigger fluid dispensing. In some embodiments, the device additionally comprises an adjustment mechanism configured to vary a size of an internal space of the housing, the internal space being configured to accommodate the reservoir. Advantageously, this configuration provides a high degree of flexibility for the current device to be used in conjunction with a variety of shapes and sizes of existing fluid reservoirs (e.g., the variety of existing designs of bottles and containers that are used in the healthcare industry for storing and dispensing eye drops). The ease of uptake of the device in relation to the wide range of such existing fluid reservoirs is thereby increased, whilst maintaining a device that is nevertheless relatively straightforward for any given subject to operate themselves. However, it will also be appreciated that the device may (additionally or alternatively) be configured to accommodate a bespoke or specifically designed bottle, instead of an existing fluid reservoir (bottle). Use of such a bespoke bottle may be useful in that such a bottle can be specifically designed to interact / integrate with other aspects of the overall device and may, for example, integrate with or otherwise work in combination with the fluid dispensing mechanism of the device for more optimal dispensing.

The adjustment mechanism may comprise a lead screw mechanism, where rotation of the lead screw mechanism is configured to cause translation of one or more components defining the internal space of the housing configured to accommodate the reservoir. Such an arrangement is relatively simple for the subject to use without requiring much (if any) additional training. Furthermore, the use of a lead screw mechanism provides a higher degree of granularity and fine control for the adjustment mechanism, allowing the device to be more flexibly tailored to suit a wide range of shapes and sizes of existing fluid reservoirs.

Additionally, the fluid delivery mechanism may comprise at least one movable element configured to apply the controllable pressure via compression of a wall of the reservoir. In some instances, the at least one movable element may be configured to contact the wall of the reservoir. Additionally, or alternatively, the at least one movable element may be configured to contact at least one side wall and/or a base wall of the reservoir upon activation of the fluid delivery mechanism.

Advantageously, this enables the device to apply pressure to the fluid indirectly by compressing the (side and/or base) walls of the reservoir using the movable element. An increased degree of flexibility in the amount of pressure applied is thereby achieved, as the amount of pressure and/or the increments with which it is applied can be relatively easily controlled. As a result, the properties of the pressure applied can be tailored according to the properties of the fluid reservoir (e.g., compressibility / flexibility of the material used to form the reservoir walls). As such, any variability caused in drop dispensing by the use of different types of fluid reservoirs may be taken into account; while nevertheless achieving a mechanism for automatically dispensing the fluid (drops) which closely simulates the usual method of administering the fluid drops (e.g., by squeezing the reservoir bottle itself by hand).

The at least one movable element may take the form of: at least one motorised rotatable unit (such as a cam); at least one motorised translatable or extendable rod / element / extension (such as a lead screw or linear actuator); or at least one electromagnetic element.

In some instances, the housing of the device may further comprise a support located on an opposite side of the reservoir to the movable element, the support being configured to act in opposition to the controllable pressure applied by the movable element. Advantageously, a (e.g., rigid lateral) support against the reactionary movement of the reservoir (in response to the pressure applied by the movable element) is provided, which limits any translational (e.g., lateral) displacement of the reservoir. As a result, deformation of the reservoir wall caused by the movable element more closely equates to a clamping / squeezing force being applied to the reservoir as a whole; and hence increases the correspondence between the amount of pressure applied by the movable element and the pressure applied (indirectly) to the fluid. As a result, the predictability with which the desired amount of fluid can be dispensed is increased. This is particularly evident as the amount of fluid within the reservoir decreases over time, and a greater amount of pressure and deformation of the reservoir is required to cause fluid dispensing. Where the pressure is applied to a side wall of the reservoir, the support may be provided to limit reactionary lateral translation / movement; correspondingly, where the pressure is applied to a base wall of the reservoir, the support may be provided to limit reactionary vertical (axial) translation. Additionally, in some cases, the support may complement a profile / shape of the reservoir that interfaces with the support to increase the support functionality robustness.

Additionally, or alternatively, in some embodiments, the fluid delivery mechanism may be configured to generate a suction pressure on the fluid in the reservoir. The application of suction (and hence negative pressure being applied effectively directly to the fluid within the reservoir) generates a force that causes the fluid to be drawn out of the reservoir and dispensed as desired; a syringe-like ‘pseudo-mechanical’ mechanism can be used in this regard. Advantageously, the use of suction obviates the need to apply force directly to the reservoir (walls) itself, thereby reducing the number of moving parts that are required to be precisely controlled to dispense a specific amount of fluid.

The device may also further comprise a fluid outflow monitor configured to detect that a predetermined amount of fluid has been dispensed from the reservoir along a fluid flow path to the subject’s eye. The predetermined amount of fluid detected by the fluid outflow monitor may correspond to the previously mentioned ‘predefined amount of fluid’ that is dispensed under the controllable pressure application, or may correspond to multiple ‘doses’ of that ‘predefined amount of fluid’ (and may hence correspond to one or more drops of fluid). Advantageously, an easily accessible and implementable mechanism for monitoring the result of the application of the controllable pressure (by the fluid delivery mechanism) is achieved; it can therefore be monitored whether an expected amount of fluid is dispensed in relation to the amount of controllable pressure applied.

In some instances, the fluid outflow monitor may comprise a light source configured to output light along an illumination axis to a detector, the illumination axis arranged to intersect with the fluid flow path. Advantageously, the use of the illumination source in this manner can enable a fine level of detail to be achieved when monitoring the amount (number and/or size of drops / droplets) of fluid dispensed, as the delivery of each drop along the axis will ‘break’ or cross the illumination axis and hence result in a detectable change in intensity that can be monitored.

Additionally, or alternatively, the fluid outflow monitor may be configured to provide confirmation to the fluid delivery mechanism that the predetermined amount of fluid has been dispensed. The fluid delivery mechanism may then be configured, upon receipt of the confirmation, to stop application of the controllable pressure to the fluid in the reservoir.

This fluid outflow monitor configuration provides an advantageous feedback mechanism that provides a high degree of control of the amount of fluid that is dispensed to the subject’s eye. The advantages of this feedback mechanism are particularly evident when it is implemented in conjunction with the automated mechanism for controlling the application of pressure to the fluid reservoir (and hence automated control of fluid dispensing initiation). For example, the sensor unit may detect that the subject’s eye is in a suitable state for drop dispensing to occur (e.g., their eye is in an ‘open’ state) and may trigger application of the controllable pressure application by the fluid delivery mechanism. Subsequently and upon detection by the fluid outflow monitor that a predetermined amount of fluid has been delivered (one or more drops of fluid, constituting some or all of the predefined amount to be dispensed), this detection of successful dispensing can be fed back to the fluid delivery mechanism to automatically cease dispensing. As a result, the entire process - from initial application of pressure to the fluid reservoir to completion of drop dispensing - can be carried out and monitored automatically, increasing the ease with which the device can be used to successfully deliver fluid to the subject’s eye in a reliable and repeatable manner, without the aid of an additional operator / healthcare practitioner.

In some embodiments, the fluid outflow monitor may be configured to: determine an amount of fluid remaining within the reservoir; and in dependence upon determination that the amount of fluid remaining within the reservoir is below a threshold value, prevent the fluid delivery mechanism from applying the controllable pressure.

Optionally, the device (using aspects / functionality of the fluid outflow monitor and/or the sensor unit) may detect the presence of one or more drops of fluid within the captured one or more images of the subject’s eye, using computer vision software programmed to identify the presence of such drops of fluid in the captured images. This enables a positive (direct) detection of fluid drops being dispensed to the subject’s eye via an alternative / additional mechanism to the (indirect) fluid detection mechanism described above which utilises the detection of a change in illumination intensity. Advantageously, this enables the amount of fluid remaining within the fluid reservoir to be taken into consideration when deciding whether it is appropriate for the device to attempt to deliver fluid to the subject’s eye. Optionally, this may be carried out by counting the number of fluid drops (and hence total fluid volume) detected by the fluid outflow monitor to have been dispensed and comparing this with an expected / known amount of fluid originally present in the reservoir. Optionally, the fluid outflow monitor comprises a weight sensor configured to detect a weight of fluid within the reservoir, which may be used to help ascertain fluid levels remaining in the reservoir.

Optionally, the device may be further configured to provide an alignment-adjustment functionality as a secondary feedback mechanism, after it has been determined that the subject’s eye is in an ‘open’ state. This process is carried out or facilitated by the sensor unit. In some instances, the device may be configured to determine, from the captured one or more image(s), one or more additional characteristics or features of the subject’s eye. For example, the processing unit may be configured to analyse the captured images and to determine characteristics of a portion of the subject’s eye that is visible in the captured image(s); such characteristics may include the size and/or position of the subject’s pupil. This may be carried out using the computer vision software mentioned above. Based on these determined characteristics, the device may then be configured to provide feedback (e.g., to the subject) to take various actions to alter one or more of the determined characteristics. For example, if it is detected (using computer vision software analysis of the captured one or more images) that the subject’s pupil is not appropriately aligned for (optimal) fluid dispensing - for example via a determination that the pupil may not be located centrally within the captured image(s) - feedback may be provided to cause the subject to alter the location of their pupil relative to the fluid dispensing path. This thereby optimises the fluid dispensing process.

The feedback itself may be provided in a variety of forms, including but not limited to the provision of one or more light sources on the device that are illuminated to inform and direct the subject regarding how the alignment alteration is to be carried out. For example, if an adjustment needs to be made to move the device in a particular direction to improve the alignment of the subject’s eye and a fluid dispensing / flow path, a light source corresponding to or associated with that direction of movement may be illuminated. In such instances, feedback to move the device to the right can be provided by illuminating a light source on the right-hand side of a portion of the device; feedback to move the device up, down or to the left may be provided in a corresponding manner by one or more correspondingly located light sources.

In some embodiments, the device may further comprise at least one fixation source configured to control the position of the subject’s eye relative to a delivery path of fluid from the reservoir. Optionally, the at least one fixation source comprises a single-point light source; and/or a video output source configured to display or project a series of images onto the subject’s eye. The presence of a fixation source can provide a mechanism to focus the subject’s eye upon a specific point / region, and thereby maintain a particular alignment of the subject’s eye with components of the device. Specifically, this allows maintenance of a constant alignment (along a fluid delivery path, for example that described above in relation to the use of the fluid outflow monitor) between the reservoir and the subject’s eye, and hence improves the rate of successful drop instillation. Advantageously, the fixation source may also provide one or more additional functionalities, and may for example provide additional illumination to the subject’s eye to improve the sensitivity of image capture (and hence eye state detection analysis) that can be achieved. Additionally, or alternatively, the fixation source may serve as a user interface and feedback mechanism for the subject / user (optionally in combination with the provision of a push button or other input mechanism) to enable (i) customised setup of the device functionality by the user; and/or (ii) customised feedback to be provided to the user in relation to the successful dispensing of fluid to the subject’s eye. For example, the fixation source may be operatively coupled to the fluid outflow monitor and may be illuminated in a specific manner (e.g., flashing, blinking) to indicate to the user the successful dispensing of a predefined / predetermined amount of fluid.

In some embodiments, the sensor unit may be configured to transmit the captured plurality of images to a remote device for subsequent analysis and monitoring of at least one of the following: an eye disease state; successful drop instillation in the subject’s eye; or adherence to a medication regimen. Advantageously, this enables the images captured to be analysed and monitored (subsequently and over time) by healthcare / medical practitioners to monitor any changing conditions of the subject’s eye, as well as the associated effects (if any) of a fluid dispensing regimen assigned. This remote monitoring ability is particularly useful where the device is being used to administer eye drops in the subject’s own home away from supervisory healthcare practitioners, as is usually the case with the above-described device. Furthermore, by digitalising the process of fluid dispensing via image capture and (remote) monitoring, detection of (eye drop) fluid dispensing activity by the subject can be achieved accurately and passively. Additionally, any data captured in this manner can be registered to an external device as a surrogate marker of medication compliance and enable the provision of feedback (to the subject) in the form of reminders for adequate daily dosing.

Additionally, in examples where (colour camera) image capture of the subject’s (eye) corneal surface is carried out during fluid (drop) instillation, this data can also be sent to the healthcare practitioner (e.g., the treating ophthalmologist) to monitor and adapt the subject’s treatment as required, thereby enabling optimal, patient-specific management.

Optionally, the device may further comprise a retaining plate, retainer or other support configured to complement / match a profile / shape / outline of at least a portion of the reservoir. Advantageously, this configuration retains the fluid reservoir more securely within the device housing and minimises (vertical) movement of the reservoir within that housing. Stability and support for the reservoir is thereby increased during activation of the adjustment mechanism and/or the fluid dispensing mechanism. In turn, the accuracy of fluid dispensing (and its correspondence with the application of the controllable pressure by the fluid dispensing mechanism) is also increased. The retainer may be provided in addition to the previously- mentioned ‘support’ that acts in opposition to the controllable pressure applied by the fluid delivery mechanism. The retainer may alternatively itself act to provide this support functionality. In some cases, the retainer may be removable and may be configured to interface with the fluid reservoir, so as to enable removal and insertion of the fluid reservoir into the device housing. The flexibility of the device to accommodate different sizes and shapes of fluid reservoir (e.g., different types of eye drop bottle) , whilst still allowing each one to be easily slotted into and out of the device (body) housing.

Additionally, or alternatively, the device may further comprise at least one support extension shaped to conform to a portion of the subject’s face and to support the device in a desired position relative to the subject’s eye whilst the fluid is dispensed. Advantageously, such an arrangement provides a stable (yet comfortable) support for the device, when in use and dispensing fluid, to rest in a particular position against the subject’s face that may enable optimal success of fluid delivery to the subject’s eye. Optionally, at least part of the sensor unit is mounted to the at least one support extension. This provides the sensor unit with an unobstructed line-of-sight view of the subject’s eye, such that image capture using that sensor unit (and the subsequent analysis and determination of whether the predetermined condition for fluid dispensing has been met) can be carried out more easily, effectively, and reliably. In some cases, one of the at least one support extension(s) - e.g., a lower support extension - is configured to retract a lower eyelid of the subject’s eye. This support extension may thereby have dual functionality associated with it - supporting the device at the correct angulation against the subject’s face for optimal fluid dispensing, and also retracting the lower eyelid for increased fluid instillation surface area.

In some cases, an interior space within the device housing accommodating the fluid reservoir may be configured to (having dimensions that are suitable for) enable removal and/or reattachment of a cover / cap of the fluid reservoir whilst the fluid reservoir remains in situ within the device housing. This enables sterility of the fluid in the reservoir to be maintained, and the reservoir to be substantially (semi) permanently retained within the device. This interior space may have a boundary that is defined by the above-mentioned at least one support extension.

According to another aspect of the present disclosure, there is provided a method for automated delivery of fluid to an eye of a subject. The method comprises detecting, by a sensor unit, whether the subject’s eye meets a predetermined condition for fluid dispensing to be carried out. The method further comprises applying, in dependence upon detection of the predetermined condition being met, controllable pressure to the fluid to cause a predefined amount of the fluid (e.g., one or more drops or droplets of fluid) to be dispensed from a fluid reservoir. The method may also further comprise detecting that a predefined amount of the fluid has been dispensed; and ceasing, in dependence upon detection of the predefined amount of fluid being dispensed, the application of the controllable pressure on the fluid.

It will be appreciated that the features and advantages described in relation to the device are also applicable to the method, and vice versa. Where such advantages have been discussed above in relation to features of the device, they will not be discussed again in relation to the corresponding method features but will be understood to be equally applicable.

For example, in some embodiments, the predetermined condition to be met corresponds to the eye of the subject being in an ‘open state’. In such cases, the method may further comprise capturing, by the sensor unit, one or more images (e.g., a plurality of images) of at least a portion of the subject’s eye; and analysing, by the sensor unit, the captured one or more images, utilising a machine learning model trained using a plurality of previously obtained images of eyes exhibiting a variety of states ranging from the ‘open state’ to a ‘closed state’. The method may further comprise determining, by the sensor unit, whether the subject’s eye in the captured one or more images meets the predetermined condition.

In some instances, the predetermined condition relates to an eye state of the subject and detecting whether the subject’s eye meets a predetermined condition for fluid dispensing to be carried out comprises detecting whether the subject’s eye state is in an ‘open state’. Optionally, determining the eye state of the subject may comprise utilising a machine learning model trained using a plurality of previously obtained images of eyes exhibiting a variety of states between ranging from the ‘open state’ and to a ‘closed state’.

In some embodiments, the method further comprises varying, by an adjustment mechanism, a size of an internal space of a housing of the device configured to accommodate the fluid reservoir. Optionally, the adjustment mechanism may comprise a lead screw mechanism, and varying the size of the internal space may comprise rotating the lead screw mechanism to cause translation of one or more components defining the internal space of the housing configured to accommodate the fluid reservoir.

In some instances, applying the controllable pressure may comprise moving or activating at least one movable element of the fluid delivery mechanism to compress a wall of the fluid reservoir. Moving the at least one movable element may comprise contacting the wall of the reservoir. Additionally, or alternatively, moving the at least one movable element may comprise contacting a side wall and/or a base wall of the reservoir upon activation of the fluid delivery mechanism. In some instances, the method may further comprise supporting, by a support located on an opposite side of the reservoir to the at least one movable element, the reservoir in opposition to the controllable pressure applied by the at least one movable element. Additionally, or alternatively, applying controllable pressure to the fluid to cause a predefined amount of the fluid to be dispensed from a fluid reservoir comprises generating a suction pressure on the fluid in the reservoir.

In some embodiments, detecting that a predefined amount of the fluid has been dispensed may comprise detecting, by a fluid outflow monitor, that a predetermined amount of fluid has been dispensed from the reservoir along a fluid flow path to the subject’s eye. In this case, the predetermined amount of fluid detected by the fluid outflow monitor may correspond to the predefined amount of fluid dispensed by the fluid delivery mechanism; or may correspond to one or more multiples of that predefined amount of fluid. Additionally, or alternatively, ceasing application of the controllable pressure on the fluid may further comprise providing, by the fluid outflow monitor, confirmation to the fluid delivery mechanism that the predetermined amount of fluid has been dispensed.

In some embodiments, the method may further comprise: determining, by the fluid outflow monitor, an amount of fluid remaining within the reservoir; and in dependence upon determination that the amount of fluid remaining within the reservoir is below a threshold value, preventing the fluid delivery mechanism from applying the controllable pressure. In some embodiments, the method may further comprise controlling, by at least one fixation source, a position of the subject’s eye relative to a delivery path of fluid from the reservoir. In some embodiments, the method may further comprise: transmitting the captured plurality of images to a remote device for subsequent analysis and monitoring of at least one of the following: an eye disease state; successful drop instillation in the subject’s eye; or adherence to a medication regimen. Additionally, or alternatively, the method may further comprise supporting, by at least one support extension shaped to conform to a portion of the subject’s face, the device in a desired position relative to the subject’s eye whilst the fluid is dispensed.

According to another aspect of the disclosure, there is provided a fluid dispensing device for automated delivery of fluid to an eye of a subject. The device comprises a housing configured to accommodate a reservoir containing the fluid for delivery and a fluid delivery mechanism configured to apply controllable pressure to the fluid in the reservoir to cause a predefined amount of the fluid (e.g., one or more drops of the fluid, or droplets if dispensed as a spray) to be dispensed from the reservoir to the subject’s eye. The features and advantages described in relation to the device of the previously described aspect may also be implemented in relation to the present device aspect, in various combinations as appropriate, even though the sensor unit and determination of a predetermined condition of the subject’s eye are not necessarily carried out in the present aspect.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1A shows a perspective view of a device according to an embodiment of the present disclosure, whilst Figure 1B shows a schematic diagram taken along a vertical cross- section through the device of Figure 1A;

Figures 2A and 2B are perspective and rear views respectively of a lower portion of the device of Figure 1A, showing a fluid delivery mechanism according to an embodiment of the present disclosure;

Figures 3A, 3B and 3C illustrate a portion of a fluid delivery mechanism suitable for use in the device of Figure 1A according to an embodiment of the present disclosure;

Figures 4A and 4B are perspective and top plan views respectively of a lower portion of the device of Figure 1A, showing an adjustment mechanism according to an embodiment of the present disclosure, where Figure 4C is an enlarged version of Figure 4B with part of a housing of the device removed to more clearly illustrate the relative arrangement of the internal components, and Figure 4D shows a schematic diagram taken along a vertical cross-section through the device of Figure 1A to show some additional components of the fluid delivery mechanism;

Figure 5 is a perspective view of a portion of the device of Figure 1 A, showing a fluid outflow detection mechanism according to an embodiment of the present disclosure; Figures 6A, 6B and 6C show vertical cross-sections through a portion of the device of Figure 1A, showing the fluid outflow detection mechanism in more detail;

Figure 7 is a flow diagram illustrating steps in a method of automated eye drop delivery according to an embodiment of the present disclosure;

Figure 8 illustrates an example scenario in which the device of Figure 1A could be used to achieve automated delivery of eye drop fluid into a subject’s eye;

Figure 9 illustrates an example scenario in which a device according to another embodiment of this disclosure could be used to achieve automated delivery of eye drop fluid into a subject’s eye;

Figures 10A and 10B show perspective and side views of a device according to another embodiment of the present disclosure, Figure 10C shows a vertical cross-section of this device and Figure 10D shows a portion of this device; and

Figure 11A shows a perspective view of a device according to another embodiment of the present disclosure, Figure 11B illustrates a portion of this device incorporating the fluid reservoir, and Figure 11C shows a vertical cross section of the device of Figure 11 A.

In the drawings, like features are denoted by like reference signs.

DETAILED DESCRIPTION

A specific implementation of the claimed disclosure will now be described in which numerous features will be discussed in detail to provide a thorough understanding of the inventive concept as defined in the claims. However, it will be apparent to the skilled person that the disclosure may be put into effect without the specific details and that in some instances, well known methods, techniques and structures have not been described in detail in order not to obscure the disclosure unnecessarily.

It should also be appreciated that the devices and techniques utilised in relation to the claimed disclosure may also be implemented outside of the medical domain, and would be applicable more generally in circumstances where fluid needs to be dispensed in a controlled manner, particularly in scenarios where it may be advantageous for fluid dispensing to take into account available fluid for dispensing and the state of an object receiving the dispensed fluid. It should also be noted that references to fluid in this document are intended to encompass a flowable material of any reasonable viscosity, provided the application of controlled pressure to the fluid-containing reservoir can result in outflow of that fluid from the device.

With reference to Figures 1A and 1B, there is provided a device for automated delivery and dispensing of fluid to an object according to an embodiment of the present disclosure. This embodiment has been envisaged to be utilised fora particular example of dispensing eye drop (medication) fluid into a subject’s eye, e.g., the device can be an eye drop dispensing device.

In its most general form, the device 1 comprises a housing 2 that is configured to retain, contain or otherwise support a reservoir 4 of fluid that is to be dispensed into the subject’s eye. The device 1 further comprises a fluid delivery mechanism 6 that is arranged to interact with the fluid reservoir 4 and to apply a controllable amount of pressure to the fluid within the reservoir 4 so as to cause a certain (predetermined or predefined) amount of fluid to be dispensed from the reservoir 4, and hence from the device 1 , into the subject’s eye. This predefined amount of fluid may correspond to one or more drops of the fluid (or droplets, if dispensed as a spray), and hence therefore correspond to a part, or the entirety, of an intended total amount of fluid to be dispensed into the subject’s eye. Additionally, the device 1 comprises a sensor unit 8 that is configured to monitor the subject’s eye and to detect whether a predetermined condition has been met for the fluid to be dispensed from the device 1. The sensor unit 8 is in operative communication with the fluid delivery mechanism 6, and upon determining that the predetermined fluid dispensing condition has been met by the subject’s eye, the sensor unit 8 is configured to activate the fluid delivery mechanism 6 (for example, via output of an activation signal from the sensor unit 8 to a processor of the fluid delivery mechanism 6), causing the fluid delivery mechanism 6 to carry out one or more actions which result in the application of the controllable amount of pressure to the fluid in the reservoir 4. The fluid reservoir 4 and fluid delivery mechanism 6 are at least partially contained within a lower housing portion 2A of the device 1 , whilst the sensor unit 8 is located on or at least partially contained within an upper housing portion 2B of the device 1.

In more detail, in order to detect the predetermined condition, the sensor unit 8 is configured to monitor the subject’s eye to detect when the subject’s eye is in an ‘open’ state - i.e. a state in which successful delivery and instillation of eye drop fluid into the eye is possible - as well as when the subject’s eye is in a ‘closed’ state (and where it is hence not possible to successfully instil eye drop fluid into the eye). In this case, the predetermined condition, detected by the sensor unit 8 that triggers activation of the fluid delivery mechanism 6 to begin applying pressure to the fluid in the reservoir 4, corresponds to a detection that the subject’s eye is in an ‘open’ state. Additional detail regarding how this detection of ‘eye state’ is implemented by the image sensor 8 will be provided subsequently with reference to the flow diagram of Figure 7. The device 1 also comprises one or more support extensions or arms 10, attached to or integrated with the housing 2 (and specifically with the upper portion of the housing 2B), which are configured to interface and conform with a portion of the subject’s face close to or around the eye. These support extensions 10 thereby support the device 1 in a particular desired orientation for optimal delivery of eye drop fluid into the subject’s eye. Additional detail regarding these support extensions 10 and their interaction with the subject’s face / eye is provided subsequently with reference to Figure 8.

Additionally, the device 1 also incorporates a fluid outflow monitor / detector (detection mechanism) 12 which monitors the fluid dispensing process, and is capable of detecting the dispensing or outflow of one or more drops of fluid from the reservoir 4. Furthermore, the fluid outflow detector 12 is in operative communication with the fluid delivery mechanism 6, such that detection results obtained by the fluid outflow detector 12 can be incorporated into information or signals that are provided by the fluid outflow detector 12 as feedback to the fluid delivery mechanism 6. Specifically, detection of successful fluid delivery from the device 1 by the fluid outflow detector 12 may be used to trigger the fluid delivery mechanism 6 to stop applying the pressure to the fluid in the reservoir 4. In other words, detection that a desired amount of fluid has been dispensed to the subject’s eye can be used to stop further fluid dispensing, and thereby more precisely control the amount of fluid that is dispensed in a given session.

A fluid delivery mechanism according to one embodiment of the present disclosure will now be described in more detail with reference to Figures 2A and 2B. These figures illustrate a lower portion 2A of the housing 2 of the device 1 which is configured to contain the reservoir 4 containing the fluid for dispensing, as well as the fluid delivery mechanism 6.

In the illustrated embodiment, the reservoir 4 is envisaged to take the form of a separate container, for example an ‘off-the-shelf eye drop solution bottle, with compliant lateral (side) walls, which when compressed using the fluid delivery mechanism 6 results in fluid outflow from a reservoir exit port 4A (e.g., the conical tip of the container). Alternatively, the reservoir 4 may take the form of a ‘bespoke’ container that may be designed specifically to interface and/or function in combination with the fluid delivery mechanism 6 utilised in the device, for optimal fluid dispensing. For example, the ‘bespoke’ container may have a specifically designed shape or form, or have other characteristics, that increases the ease of interaction with and compression by the fluid delivery mechanism 6. It would be appreciated by the skilled person however that this reservoir 4 can alternatively assume the form of any other differently- sized or shaped fluid container; how such bottles may be accommodated within the current device 1 will be described in greater detail subsequently in relation to Figures 5 and 6A to C. In fact, it is noted that the device 1 can be used with a wide range of existing eye drop medication containers, and can therefore be implemented more generally as a universal eye drop applicator across the healthcare sector. In some cases, the reservoir 4 may alternatively take the form of an integrated fluid reservoir, where the device 1 comprises an internal chamber having compliant lateral walls which can be compressed using the fluid delivery mechanism 6 in a corresponding manner to that of the separate off-the-shelf container. The removable containers, as well as any integrated fluid reservoir, could be manually filled by the user.

The fluid delivery mechanism 6 in the illustrated embodiment functions by applying (focal) compression to one or more lateral (side) walls 4B, 4C of the fluid-containing reservoir 4. In this specific embodiment, the fluid delivery mechanism 6 takes the form of a cam 14 (in this instance, a fixed triangular cam) positioned in proximity to one of the lateral walls 4B of the reservoir 4, and arranged at a distance from the reservoir 4, such that anticlockwise / clockwise rotation of the cam 14 brings the edges 14A and vertices 14B of the cam 14 into contact with the lateral wall 4B facing the cam 14. This contact and the compressive force generated via the rotation of the cam 14 gradually or incrementally deforms the lateral wall 4B of the reservoir 4 until sufficient pressure has been exerted to cause one or more drops of the fluid in the reservoir 4 to be dispensed (corresponding to some or all of an intended total amount of fluid for dispensing).

Controlled rotation of the cam 14 in this manner is achieved in the illustrated embodiment by a motor 16 connected to the cam 14 via an axle 18 that traverses the cam 14. This motor 16 may take the form of a single, closed-loop control, 1 :100 geared stepper motor for example; the motor unit may be connected to an H-bridge motor driver mounted onto a processing unit (not shown), enabling high fidelity control of stepper motor position, velocity and directionality of rotation, and torque. This in turn provides a greater degree of controllability for degree of movement, and hence the corresponding amount of pressure, that can be exerted by the cam 14 on the lateral wall 4B of the reservoir 4. Furthermore, as shown in the figures, it will be appreciated that the vertices 14B of the cam 14 have a filleted morphology - i.e., the vertices are rounded rather than being sharply / acutely angled - and that the edges 14A of the cam 14 are also rounded or curved. This improves the ability of the cam 14 to apply a controllable incremental pressure to the fluid reservoir 4 with each incremental rotational movement of the cam 14. This improves the degree of (fine) control functionality provided in relation to fluid (drop) dispensing from the fluid reservoir 4. This improvement in control of the pressure applied, as a result of the shape and morphology of the cam 14, also reduces the amount of torque that needs to be applied by the motor 16.

It will be noted that the axle 18 of the motor 16 in the illustrated embodiment passes through the centre of the cam 14. However, an alternative arrangement is envisaged in which the axle 18 is laterally offset from the centre of the cam 14 - i.e. , an acentric cam is used. This alternative arrangement can advantageously deliver higher focal pressure upon the lateral wall 4B of the fluid reservoir 4, but with correspondingly lower angles of rotation by the stepper motor. Such a mechanism is therefore useful for less compliant, more rigid fluid reservoir walls; however, it does require a higher power motor and higher gear ratio configuration capable of delivering more torque, without stalling.

As has been briefly discussed above, control of the motor 16 (and thereby of the compressive forces applied by the cam 14) can be linked to the fluid outflow detector 12 via a feedback loop to a processing unit (now shown) controlling the motor 16. Specifically, when the fluid delivery mechanism 6 is activated, this causes the motor 16 to rotate the cam 14 to perform incremented compression of the reservoir’s lateral wall 4B until a successful drop dispensing event has occurred - e.g., a drop of fluid is detected by the fluid outflow detector 12 to have been dispensed from and exited the reservoir 4. For example, this may involve the motor 16 performing one or more rotational increments of the cam 14, each increment being a rotational angle of around 10 degrees or so. However, once a successful drop dispensing event is determined to have occurred, the fluid outflow detector 12 can then cause the motor 16 to release / decrease the pressure applied - for example, by reversing the rotation direction of the cam 14 by an equivalent number of incremental steps as was required to enable successful drop delivery. Once this is complete, the fluid delivery mechanism 6 would then be returned to its ‘neutral’ state - i.e., where the components return to the original state prior to activation and before the compression forces were triggered to be applied.

This dynamic approach to compression of the fluid reservoir 4, in response to detection of a successful drop dispensing event, enables the device 1 to tailor the amount of pressure that is applied based on various properties of the fluid and the reservoir 4 itself. For example, this feedback between activation of the fluid delivery mechanism 6 and the fluid outflow detector 12 allows greater compression to be automatically applied to the lateral wall 4B of the fluid reservoir as the total fluid volume contained within the reservoir depletes over multiple uses. In the illustrated embodiment, a substantively rigid lateral support 20 is provided within or as part of the housing 2 (for example, in the form of an extrusion). This support 20 is located proximate to (and in contact with) a lateral wall 4C of the reservoir 4 - the wall which is located on an opposite side of the reservoir 4 to the lateral wall 4B which undergoes compression by the fluid delivery mechanism 6 - and extends substantially the entire length of that lateral wall 4C. The provision of this support 20 limits lateral (translational) displacement of the reservoir 4 as the cam 14 (and particularly its vertices) contacts and deforms the opposite lateral wall 4B of the reservoir 4. The presence and location of this support 20, acting against lateral wall 4C in opposition to the compression forces exerted by the cam 14 upon contact with opposite lateral wall 4B, thereby increases the correspondence between rotation of the cam 14 and subsequent fluid dispensing. This enables fluid to be dispensed more easily and accurately from the device 1. The advantages of such lateral support are further highlighted as the fluid volume within the reservoir 4 decreases over multiple uses, as the magnitude of the intra reservoir pressure that must be generated (proportional to the degree of rotation of the cam 14 and force of compression) and exerted upon the fluid within the reservoir 4 to dispense a single fluid drop increases with a decreasing amount of fluid present in the reservoir 4.

Alternative fluid delivery mechanisms are also envisaged in other embodiments. For example, the cam 14 could be replaced by a translatable element or rod (configured in a similar manner to a piston, for example), preferably having a tapered end for focussed pressure application to the reservoir lateral wall 4B whilst avoiding the possibility of piercing or puncturing that wall. In order to achieve easily repeatable incremental changes in the amount of compression applied for this alternative arrangement, a rack with teeth along its long edge may be provided in combination with a pinion or gear that is rotatable by a motor (which could correspond to motor 16 described above). This enables the translatable element to be reversibly driven against the lateral wall 4B of the reservoir in an easily repeatable, incremental manner. Alternatively, if instead the shaft of the motor 16 were to be combined with a threaded cylinder, revolution of the motor shaft and thus the threaded cylinder (in relation, for example, to a fixed position elongated, threaded nut), would provide a corresponding amount of controllable compressive force to the lateral wall 4B of the fluid reservoir. With sufficient rotation, this mechanism could deliver higher compressive forces than the illustrated embodiment utilising the cam 14, but at significantly slower speeds.

A further alternative embodiment is envisaged involving a pair of magnets, in which the cam 14 and motor 16 combination in the fluid delivery mechanism 6 is replaced by an electromagnet connected to a power circuit. A second magnet (for example, a ferrous magnet to decrease the associated weight of this mechanism) would be located in proximity to the opposite lateral wall 4C of the reservoir 4, for example embedded within a recess in the support 20 (if one is provided), or in the wall of the housing 2 (if no support is provided). This second magnet would be capable of extending from its recess when pulled by the electromagnet (upon activation). The magnetic attraction between the two magnets would therefore provide a corresponding compressive force to the lateral walls 4B, 4C of the reservoir 4; and the degree of compressive force provided by the magnets could be tuned by increasing the voltage provided to the electromagnet (and hence its magnetic attractive strength). As a further alternative, it is envisaged that the piezoelectric effect could be utilised to provide a ‘self clamping piezo motor’. In more detail, two clamping components made of piezoelectric materials could be used in place of the pair of magnets described above, positioned in proximity to opposite lateral walls 4B, 4C of the reservoir 4. The application of electric power (voltage) to the clamping components will cause them to extend and apply clamping forces to the corresponding walls of the reservoir 4. The use of such ‘piezo motors’ allows a corresponding clamping effect (to that described above in relation to magnetic components) to be achieved, without the use of magnetism, rendering the device particularly suitable in high-magnetic environments or environments where magnetic disturbance would be an issue (e.g., hospitals, patients with pacemakers).

As another alternative, it is envisaged that an ‘iris’ mechanism creating a modifiable aperture - a mechanism formed of rotatable elements or plates, arranged such that rotation of these elements in one direction increases the size of a central opening / aperture within the mechanism and rotation of the elements in the opposite direction decreases the size of that central aperture - could be used in an alternative fluid dispensing mechanism 6’ to replace the cam 14 and support 20 combination in the fluid dispensing mechanism 6 shown in Figures 2A and 2B. Such an alternative fluid dispensing mechanism 6’ is illustrated in different orientations in Figures 3A, 3B and 3C. As shown in this figure, the iris (fluid dispensing) mechanism 6’ comprises a plurality of interacting sub-component ‘leaflets’ 21A sandwiched between a pair of rotary plates 21 B, 21C, at least one of which is movable. The morphology of the leaflets 21A and the angulation of tracks 21 D provided within the upper/lower rotary plates 21 B, 21C guides the motion of respective leaflets 21A (via the use of pins 21 E that are provided contiguous with the leaflets 21A and which each move within and along a corresponding one of the tracks 21 D) during rotation of the movable rotary plate(s) 21 B, 21C. In the illustrated embodiment, clockwise rotation of the upper rotary plate 21 B (with the lower rotary plate 21C remaining fixed in place) narrows the aperture ‘A’ formed by internal walls of the leaflets as a result of collective movement of the leaflets 21 A; conversely, anti-clockwise rotation results in dilation of this aperture ‘A’. Such rotation of the plates about the central axis of the aperture can be performed manually or through a motorised mechanism (for example, using the motor 16 described above). In this alternative embodiment, the reservoir 4 could be located within the central aperture of the iris mechanism, such that closing of the aperture would apply compressive force effectively simultaneously to the lateral walls 4B, 4C of the reservoir 4. Advantageously, this embodiment would be able to accommodate various container diameters more easily. Nevertheless, such an iris mechanism, in comparison to the illustrated cam 14 mechanism, would require a larger body size of the device 1 for excursion (the path swept out in the course of rotational movement) of the leaflets 21 A during dilation of the aperture.

A further alternative embodiment (not shown) is also envisaged in which a ‘pseudo mechanical’ mechanism is utilised to withdraw fluid from a fluid container having a tapered tip. In this embodiment, a semi-sealed antechamber could be provided, enclosing the exit port 4A of the reservoir 4, where negative pressure would be generated in the antechamber. This negative pressure may be generated by, for example, employing a pneumatic, syringe-based system utilising the antechamber as a ‘syringe chamber’ and incorporating a plunger element. This plunger element could be operated in the syringe chamber by a motorised mechanism, akin to the motorised mechanism earlier in relation to the translatable piston element for example. Controllable negative pressure could then be generated within the antechamber by withdrawing the plunger element, which would in turn exert (negative) pressure on the fluid in the reservoir 4 and cause the fluid to be drawn out of the reservoir 4 and into the antechamber. Subsequent advancement of the plunger element (back into the antechamber) would then increase the pressure within the antechamber to dispense fluid from an outflow aperture provided in the antechamber.

When using this pseudo-mechanical mechanism, there is a risk of residual fluid fouling on internal walls of the antechamber which have been brought into contact with the fluid (as, unlike the other above-described embodiments, the fluid is not dispensed directly from the reservoir 4 to the external environment); subsequent fluid cross-contamination may then occur if differing fluid types are utilised with the same device 1. Fluid interacting surfaces within the device 1 can therefore also be provided with a hydrophobic coating to repel water-based fluid solutions as they are drawn and dispensed through the antechamber.

It is also noted that if the compressive forces are generated at a sufficient rate by the fluid delivery mechanism 6, particularly in combination with the provision of a narrow outflow region (e.g., exit port 4A) in the device 1 that comprises multiple perforations, fluid can be dispensed from this mechanism as a spray (rather than drop by drop). Compared to drops, this method of instillation may prove gentler to the user’s eye and enables wider surface area fluid coverage of the receiving eye.

With reference to Figures 4A to 4D, additional details of the device 1 and its housing 2 will now be described. The device 1 comprises an adjustment mechanism 22 which is configured to alter (a size or dimension of) an internal space or chamber within the housing 2 that is intended to accommodate the fluid reservoir 4. In the illustrated embodiment, this internal space is defined as the space between the pair of components exerting pressure in opposition on the fluid reservoir 4 - namely the space formed between the fluid delivery mechanism 6 and the lateral support 20. This mechanism thereby allows the device 1 to accommodate a range of differently sized and shaped fluid reservoirs 4, increasing the flexibility of the device 1 for use in tandem with a variety of existing eye drop containers and bottles. The ability to adjust the internal space within the housing 2 to suit the size and/or shape of the fluid reservoir 4 that is being used ensures that the reservoir 4 can still be securely retained within the housing 2 whilst the compressive forces are being applied by the fluid delivery mechanism 6, regardless of the form taken by the reservoir 4.

In the illustrated embodiment, the adjustment mechanism 22 is configured to adjust the relative location of the fluid delivery mechanism 6 (i.e. , the cam 14 and motor 16), and of the support 20 acting in opposition to the fluid delivery mechanism 6. In this instance, it will be appreciated that the support 20 is therefore translatably-movable. In more detail, the adjustment mechanism 22 corresponds to a translatable lead-screw mechanism comprising a main shaft 24 attached to an outer surface of the housing 2 and incorporating a pair of threaded lead screw portions 24A, 24B arranged laterally along the shaft 24; each screw portion 24A, 24B covers around half of the shaft 24. The screw portions 24A, 24B are positioned proximate to either the fluid delivery mechanism 6 or the lateral support 20; and are coupled to the corresponding one of those internal components (i.e., the fluid delivery mechanism 6 or the support 20) via respective complimentarily-threaded mounts 26A, 26B.

The coupling between the main shaft 24 of the adjustment mechanism 22 and internal compression-generating components 6, 20 via the lead screw portions 24A, 24B and mounts 26A, 26B enables lateral translation of each corresponding component 6, 20 to occur upon rotation of the shaft 24. Specifically, in the illustrated embodiment, the two screw portions 24A, 24B have opposite ‘handed’ threads: the screw portion 24A corresponding to the fluid delivery mechanism 6 utilises a left-hand threaded model; whilst the screw portion 24B corresponding to the lateral support 20 utilises a right-hand threaded model. As a result, when the shaft 24 is rotated, this causes simultaneous relative lateral translation of the device internal components 6, 20 in opposite directions depending on the overall direction of rotation of the shaft 24. Hence, rotation of the shaft 24 in one direction reduces the lateral separation between the fluid delivery mechanism 6 and support 20 (thereby reducing the amount of space available to receive the fluid reservoir 4); rotation of the shaft 24 in the opposite direction increases the relative separation between the fluid delivery mechanism 6 and support 20 (thereby increasing the amount of space available to receive the fluid reservoir 4). The above- described adjustment mechanism 22 therefore provides a high degree of flexibility for the device 1 to accommodate a variety of different eye drop container shapes, whilst also minimising the number of moving parts required.

To provide additional support for retaining the reservoir 4 securely within the housing 2, the housing 2 comprises a removable top retaining plate 28 that can be inserted across an upper surface of the portion of the housing 2 which houses the fluid reservoir 4 (as shown in the illustrated embodiment of Figures 4A and 4B, this is the lower housing portion 2A). The retaining plate 28 is configured to interface with a portion of the fluid reservoir 4 (for example, in the illustrated embodiment, this interface occurs at or near the neck of an eye drop bottle) to retain the reservoir 4 more securely within the housing 2, and thereby minimise vertical movement of the reservoir 4 (especially during compression and fluid dispensing). More specifically, the retaining plate 28 comprises a notch, slot or cut-out 28A which is configured to interface with the reservoir 4 via a ‘snap-fit’ mechanism: at least a portion of an outline of the cut-out 28A is shaped and sized to match an external circumference and profile of the portion of the reservoir 4 with which the retaining plate 28 interfaces. The reservoir 4 can therefore be inserted into the cut-out 28A and securely held therein. The use of the retaining plate 28 and its integral notch 28A provide increased stability and support for the fluid reservoir 4 when the adjustment mechanism 22 and/or the fluid delivery mechanism 6 are activated. In the illustrated case, the internal outline of the cut-out 28A is configured to match the external profile of the neck of the eye drop bottle; however, it will be appreciated that other configurations may be used provided a corresponding retention and support functionality is achieved - for example, as will be shown and described subsequently with reference to Figures 10A to 10D.

To enable low resistance rotation and one-to-one mapping of motor axle 18 and cam 14 motion, a (cylindrical) extrusion or extension 30 is provided on a face of the cam 14, facing an inner wall of the housing 2 which is proximate to the adjustment mechanism 22. This extrusion 30 is configured to be received within a circular metal bearing 31 (for example, a 6mm / 4mm [Outer Diameter / Inner Diameter] bearing), as shown more clearly in Figures 4C and 4D. This configuration provides axial rigidity across the length of the cam 14 and motor 16 unit, thereby facilitating translation of the cam 14 and motor 16 unit by the adjustment mechanism 22. Furthermore, during the fluid dispensing process when the reservoir 4 is undergoing compression by the cam 14, this additional axial rigidity provided by the extrusion 30 mitigates undesirable flex along the axis of rotation of the cam 14 for consistent compression.

Further details regarding the fluid outflow detector 12 will now be provided with reference to Figures 5 and 6A, 6B and 6C. In the illustrated embodiment, the fluid outflow detector 12 is provided within the upper housing portion 2B. More particularly, this upper housing portion 2B is positioned in a location above, and corresponding generally to the footprint of, the reservoir 4, and comprises side walls 2C that extend upwards from an upper surface of the lower housing portion 2A (for example, from the retaining plate 28). These side walls 2C are configured to surround the exit port 4A of the reservoir 4 (in the illustrated example, this exit port 4A corresponds to the tip of the eye drop container). Furthermore, the inner surfaces of these side walls 2C are made of or coated with a material having a low-reflectance property.

The fluid outflow detector 12 comprises a light emitter-detector pair 12A, 12B mounted on opposing side walls 2C of the upper housing portion 2B. In the illustrated embodiment, the light emitter 12A takes the form of a light source (preferably an LED, emitting light at visible or infrared wavelengths), whilst the light detector 12B takes the form of, for example, a photodiode sensor array specific to the wavelength of the LED light source. The light emitter 12A is configured to project light towards the light detector 12B, along an illumination axis T that intersects with a flow path ‘F’ along which the dispensed fluid will flow outwards from the reservoir 4 and towards the subject’s eye. In the illustrated embodiment, the light emitter 12A and light detector 12B are arranged on an outer side of their respective side walls 2C, and apertures 32A, 32B are provided in respective side walls 2C to allow light to reach the light detector 12B. In the illustrated embodiment, a relatively narrow aperture 32A is provided (around a mm or so) in the side wall corresponding to the light emitter 12A (this is illustrated in Figures 5 and 6B). This is used to collimate the light from the light emitter 12A and thereby minimise disturbance of the user’s gaze (when viewed obliquely) due to stray light emittance. By contrast, the aperture 32B provided in the side wall corresponding to the light detector 12B is wider (around several mm, for example 8 to 10 mm); this is illustrated in Figures 5 and 6C. This provides a larger receptive field to detect fluid outflow beyond the midline of light projection, and this enables fluid to be dispensed when vertical or tilted to up to 70 degrees in this device 1.

In use, when discrete drops of fluid are dispensed from the reservoir 4, the passage of a drop of fluid intersecting / crossing the illumination axis T refracts and reflects the collimated light projected along that axis, thus attenuating the total amount of light detected by the light receiver 12B. As a result, a momentary decrease in the signal intensity recorded by the light receiver 12B (as compared with average values over a previous period of time) can be inferred as a successful dispensing of a drop of fluid. Alternatively, for continuous fluid dispensing, the sustained interruption of this optical path results in a consistently decreased signal intensity registered by the light receiver 12B during the fluid dispensing process.

The ability to detect the outflow / dispensing of a drop of fluid from the reservoir 4 further enables the implementation of a drop counter functionality within the device 1 - a processing unit (not shown) within the device 1 can utilise information obtained from the fluid outflow detector 12 to monitor the number of drops dispensed from the device over time (for example, by associating a timestamp with each detection of a successful dispensing event). Where the device 1 is configured to be in communication with a remote device (e.g., a mobile device or server used by the subject and/or a healthcare practitioner), the information obtained from the fluid outflow detector 12 (and/or the information regarding the number of drops dispensed) can be transmitted to this remote device. This recording of medication usage data (i.e., the fluid drop dispensing detections) over time (e.g. with associated timestamps) enables the ascertainment of treatment characteristics, including compliance, duration of therapy, total medication dosing etc to be more readily obtained. For the younger user population, this data can also be harnessed in a secondary usage for gamification and goal-based therapy.

Furthermore, the fluid outflow detector 12 can be used to automatically ascertain a particular ‘dispensing endpoint’ - namely, when the maximal amount of fluid / maximal number of fluid drops from the reservoir 4 has been dispensed. For example, the fluid outflow detector 12 (or another processing unit within the device 1) may be configured to calculate this endpoint based on knowledge of (i) the initial ‘full’ volume of the reservoir 4, and (ii) the volume of fluid that is known to be contained within a dispensed drop or amount. The subsequent deduction of the known initial ‘full’ fluid reservoir volume with each drop / dispensed amount detected by the fluid outflow detector 12 enables the depletion over time of the fluid within the reservoir 4 to be monitored. As a result, the device 1 can avoid unnecessary fluid reservoir compression in the absence of available fluid for dispensing. In alternative embodiments, a weight sensor (not shown) could be provided in the housing 2 (for example, at or near the base of the fluid reservoir 4) to monitor the total mass of the fluid reservoir, and thereby ascertain when the reservoir 4 has reached an ‘empty’ state. For example, the known weight of the empty fluid reservoir may be input to the weight sensor, and subsequent detection that this known weight has been reached following progressive drop dispensing events, will indicate that the reservoir 4 has reached its dispensing limit. Further drop dispensing attempts by the fluid dispensing mechanism 6 can thereafter be prevented.

Further details regarding the sensor unit 8 and its role in the detection of the subject’s ‘eye state’ will now be provided with reference to Figure 7, along with a more detailed description of a method of operation of the device 1.

As noted earlier in relation to Figure 1A, the sensor unit 8 is mounted to the upper housing portion 2B of the device 1. More specifically, in the illustrated embodiment, the sensor unit 8 is mounted on and attached to one of the support extensions 10 that extends from (and can be considered to form part of, or otherwise constitute an extension of) the upper housing portion 2B. The location of the sensor unit 8 at this uppermost portion of the device 1 optimises the location of the sensor unit 8 relative to the subject’s eye, and facilities the ability of the sensor unit 8 to obtain a clear, unobstructed line-of-sight view of the subject’s eye before, during and after drop dispensing. More particularly, the sensor unit 8 comprises an image capture device 8A (for example, a colour camera unit) which, by virtue of its position and arrangement on the device 1 , is configured to capture images of the subject’s eye. In the illustrated embodiment, the captured image frames would include at least portions of the eye from the medial to lateral canthus, and margins of the upper and lower eyelid. Additionally, the sensor unit 8 comprises a processing unit or processor 8B (which may take the form of, for example, a programmable circuit board or PCB) operatively coupled to the image capture device 8A. The processing unit 8B is programmed with software to enable the determination, based upon the captured images, of the state of the subject’s eye substantially in real-time.

In more detail, the programmed software in the processing unit 8B may include some form of computer vision software or algorithms, for example utilising machine (deep) learning models, which have been trained to detect ‘open’ and ‘closed’ eye states of a subject using a training data set of images comprising subject eyes in a variety of states ranging from fully ‘open’ to fully ‘closed’. Such image data may include images of one eye on its own, images of the pair of eyes of a subject, as well as images of some or all of a subject’s face (including the eyes). The machine learning model may use this training dataset of images to learn various important features associated with the subject’s eye, and identify key indicators / characteristics that would enable the model to subsequently classify an image showing an eye as ‘open’ or ‘closed’. Various existing techniques can be used during the training process. For example, using ‘hough circular transforms’ to identify the eye and the pupil in each image of the training data, and then applying the results of this training to the captured images. A further approach can be used to identify the eye aspect ratio and define / threshold the eye as being ‘closed’ below a specified aspect ratio level. This latter approach requires images to be labelled with very specific points over the borders of the eye. Alternatively, a modified eye aspect ratio approach can be taken with multiple further points including discounting of certain features to increase the accuracy of detection. In greater detail, an initial image database was created and populated with a variety of images of different sizes of eyes, each image being labelled with regard to an ‘eye open’ or an ‘eye closed’ state. This image database was then augmented using multiple methods of augmentation such as image cropping, brightness and contrast adjustment, image rotation etc; thereby increasing the total number of images stored in the database upon which the machine learning model could be trained. The machine learning model was initially trained using a deep learning methodology based on a convolutional neural network (U-Net) architecture, using a pre-trained model as a base, and then fine-tuned using the labelled image data in the image database. A state-of-the-art loss and optimiser were used to ensure high accuracy and AUC score (Area Under the Curve score - an evaluation metric for binary classification of eye state). The machine learning model was thereby optimised and was subsequently adjusted to perform on mobile microprocessors (for example, utilising machine learning architecture that is particularly suitable for use on microprocessors and/or processors with lower processing capacity).

Once trained, the model / algorithm can then be used by the processing unit 8B to analyse the images in real-time as they are obtained by the image capture device 8A, to recognise the subject’s eye state at any given time; the sensor unit 8 can thereafter output results of the subject’s eye state determination in real-time to the fluid delivery mechanism 6. In other words, the sensor unit 8, and the results of the ‘eye state’ determination carried out by the sensor unit 8, can be programmatically linked to the actions undertaken by the fluid delivery mechanism 6. This will now be described with reference to the method 100 of automated drop delivery illustrated in Figure 7.

The method 100 begins with the correct positioning 105 of the device 1 in relation to the subject’s eye (for example as shown in Figure 8), such that a line-of-sight of the sensor unit 8 (and its image capture device 8A) to the subject’s eye can be achieved. The correct positioning of the device 1 (and especially of the exit port 4A of the reservoir 4) relative to the subject’s eye can be controlled and assisted utilising a predefined fixation point. To this end, the device 1 further comprises a fixation source 34, for example a low intensity light source such as a microLED, which is mounted on the upper portion 2B of the housing 2. In the illustrated embodiment shown in Figure 1A, the fixation source 34 is positioned on one of the support extensions 10. In this case, the same support extension 10 to which the sensor unit 8 is mounted, thereby providing a corresponding line-of-sight view from the fixation source 34 to the subject’s eye. In the illustrated embodiment, it is envisaged that the fixation source 34 may provide some or all of the following functionality.

Where the fixation source 34 is operated in a substantially constant, low-intensity illumination mode, it can provide a visual cue for ensuring a stable gaze of the subject during the automated drop instillation process; and additionally can also ensure optimal positioning of the subject’s eye after drop instillation to enable maximal medication drainage into the conjunctival sac or for uniform fluid coverage over the surface of the eye. Additionally, in this mode of operation, the fixation source 34 can provide additional illumination of the subject’s eye to improve the sensitivity of the image capture and eye state detection that is carried out by the sensor unit 8. This can be particularly useful if the camera or other sensor used in the image capture device 8A has a poor low light video exposure compensation.

Furthermore, the fixation source 34 may have the ability to provide a high intensity light output. In this instance, the fixation source 34 may act as a ‘flash’ (when being momentarily activated to its highest brightness setting) in tandem with still image capture by the image capture device 8A, to enable high contrast imaging of the subject’s eye.

Alternatively, and particularly when the device 1 is used for eye drop dispensing to children (who may be more restless during drop delivery), this fixation source 34 may include or be replaced by an image / video display (which may instead be offset from the device 1 itself) to distract the child’s attention during drop dispensing.

In some embodiments, it is also noted that the fixation source 34 may provide further functionality in relation to ‘eye state’ detection. In such embodiments, the fixation source 34 may be used to illuminate the subject’s eye, and reflected light from certain portions of the subject’s eye may be captured (for example, by the image capture device 8A and/or by another component of a light sensing arrangement, such as a light dependent resistor or LDR); the properties and the amount / intensity of reflected light captured may be used to ascertain the eye state of the subject’s eye. In more detail, increased (corneal) reflectance, from the tear film, of the illuminating light emitted by the fixation source 34 can be captured / detected (e.g., by an LDR); this increased reflectance can be used to determine that the subject’s eye is in an open state (since if the eye was in a closed state, such increased reflectance would not occur). The response of the LDR to the increased reflectance may be used to provide feedback regarding the ‘eye state determination’ in a corresponding manner to the ‘eye state’ determination feedback described above in relation to the use of image processing.

Thereafter, once correct positioning of the device 1 relative to the subject’s eye has been achieved, the process of eye state detection can be activated at Step 110 by, for example, a manual push of a button (not shown) located on the device 1 and connected to the sensor unit 8. Alternatively, it would be possible for this process to be remotely activated via the communication of a ‘start’ signal from a remote device to the sensor unit 8. Following activation of the eye state detection process, the image capture device 8A is configured at Step 115 to capture one or more (e.g., a series of) image frames of the eye (this may alternatively take the form of a video capture, with an additional intermediate step whereby individual ‘still’ image frames are extracted at intervals from the captured video). The processing unit 8B is configured to analyse the captured images using the vision software programmed therein and to determine at Step 120 the subject’s eye state at a particular point in time.

If it is determined at Step 120 that the subject’s eye is in an ‘open’ state, the processing unit 8B can be configured to provide an activation signal of some form to the fluid delivery mechanism 6, thereby activating the fluid delivery mechanism 6 to carry out its pre programmed series of actions in Step 125 in order to exert compressive force to the fluid within the reservoir 4. Prior to receiving this activation signal, the fluid delivery mechanism 6 and its constituent component(s) may be in an initial ‘neutral’ starting state. This activation of the fluid delivery mechanism 6 is maintained until at least one drop of fluid is determined in Step 130 by the fluid outflow detector 12 to have been successfully dispensed - i.e., a successful drop dispensing event.

Once a successful drop dispensing event has been detected, it is ascertained in Step 135 whether further drops are required to be dispensed. If so, the fluid delivery mechanism 6 is configured to continue the required actions necessary for applying the compressive forces to the fluid in the reservoir 4 until it is determined (e.g., by the fluid outflow detector 12) that the appropriate amount of fluid has been dispensed to the subject’s eye. Thereafter, the fluid delivery mechanism 6 is configured in Step 140 to stop applying the compressive pressure, and instead to reverse the actions that were taken during the drop dispensing process, to relieve the compressive forces applied to the fluid in the reservoir. This results in the components of the fluid delivery mechanism 6 returning to their initial starting (‘neutral’) positions / states.

As part of the eye drop fluid dispensing process 100, the device may be further configured to provide an alignment-adjustment functionality as a secondary feedback mechanism, after it has been determined at Step 120 that the subject’s eye is in an ‘open’ state. This thereby optimises the fluid dispensing process. In more detail, the device may be configured to determine, from the captured image(s), one or more additional characteristics or features of the subject’s eye. This process is carried out or facilitated by the sensor unit 8. For example, the processing unit 8a may be configured to analyse the captured images and to determine characteristics of a portion of the subject’s eye that is visible in the captured image(s); such characteristics may include the size and/or position of the subject’s pupil. This may be carried out using the computer vision software mentioned above. Based on these determined characteristics, the device may then provide feedback (e.g., to the subject) to take various actions to alter one or more of the determined characteristics. For example, if it is detected (using computer vision software analysis of the captured one or more images) that the subject’s pupil is not appropriately aligned for (optimal) fluid dispensing - for example via a determination that the pupil may not be located centrally within the captured image(s) - feedback may be provided to cause the subject to alter the location of their pupil relative to the fluid dispensing path.

The feedback itself may be provided in a variety of forms, including but not limited to the provision of one or more light sources on the device that are illuminated to inform and direct the subject regarding how the alteration is to be carried out. For example, if an adjustment to the device needs to be made to move the device in a certain direction for better alignment, a light source corresponding to or associated with that direction may be illuminated. Specifically, feedback to move the device to the right can be provided by illuminating a light source on the right-hand side of a portion of the device; feedback to move the device up, down or to the left may be provided in a corresponding manner by a correspondingly located light source. Such light sources may take the form of individual / discrete light sources (such as LEDs) positioned at particular locations on the device which are visible to the subject; and/or may take the form of a ring-shaped light source (e.g., a ring-shaped LED) having individually-illuminable portions / sections. If, however, it is determined at Step 120 that the subject’s eye is in a ‘closed’ state, or indeed if this is determined to be the case at any point during the subsequent steps whilst the fluid delivery mechanism 6 is operational during active drop dispensing, the fluid delivery mechanism 6 is configured in Step 145 not to take any action, or to temporarily ‘pause’ any actions that are being taken, to apply the compressive forces (for example, operation of the motor 16 is paused) until it is determined that the subject’s eye has returned to an ‘open’ state. The method step flow therefore returns to Step 115 and the determination of eye state in Step 120 is carried out.

The eye drop dispensing process 100 is considered to be completed once the desired amount of fluid has been dispensed to and instilled into the subject’s eye, and the various components of the fluid delivery mechanism 6 have returned to their original ‘neutral’ states.

Additional processing and analysis can be carried out during the eye drop dispensing process of Steps 130 to 140, or even after the entire process is completed. For example, in some embodiments, it is envisaged that the image capture device 8A is arranged and oriented to maintain a line-of-sight view of the portion of the subject’s eye where the drop of fluid is to be delivered / instilled. This enables ascertainment of successful drop delivery as well as confirmation of the location of the drop delivery within the eye. For example, one or more drops of fluid could be positively (and directly) detected to be present in one or more of the images captures of the subject’s eye by the image capture device 8A, using the computer vision software or algorithms implemented in the processing unit 8B. In such example, the computer vision software or algorithms may be programmed and trained to identify the presence of fluid drops within the captured images, using corresponding methods to those described above in relation to the methods used for the identification of eye state. As a proxy or indicator of successful drop instillation, the corneal reflex of the eye to foreign bodies (e.g. the fluid drop) can also be visually detected by the increased number of blinks in a given time period: such reflexes will manifest in the images captured by the image capture device 8A and can be determined using the associated processing unit 8B. Additionally or alternatively, it is noted that it would be possible to implement drop detection using the image capture device 8A and processing unit 8B in an analogous manner to the way in which the subject’s eye state is determined, if the drops are delivered into the eye along the line of sight of the image capture device 8A. For example, the programmed software in the processing unit 8B may include some form of computer vision software or algorithms, for example utilising machine (deep) learning models, which have been trained to detect ‘drop present / delivered’ and ‘drop not present / not delivered’ eye states of a subject using a training data set of images comprising subject eyes in a variety of states where drops of fluid are present in the vicinity of the subject’s eye.

Furthermore, it is envisaged that the eye image data captured and processed by the sensor unit 8 can be used for longitudinal monitoring of eye disease state. In particular, some embodiments are envisaged in which an illumination source can be provided in the device 1 , which is arranged for (direct) illumination of the anterior aspect of the eye and corneal surface; variation of this lighting morphology and focal length of the camera which forms the image capture device 8A can thereby enable ‘slit lamp’ equivalent photography. This can reveal various properties or characteristics of parts of the subject’s eye. For example, in instances of corneal injury in the subject’s eye, it is envisaged that the time-series eye image data captured in this manner (as a function of time) could be transmitted to a remote / peripheral device. This remote device may be programmed with computer image analysis software for analysis and determination of disease amelioration, stability or deterioration; additionally or alternatively, such image data could be provided (via the remote device) to a healthcare professional for human interpretation. In this latter implementation, the eye image data could be transferred over a wired / wireless connection (e.g., via Bluetooth) to a mobile application for secure storage of images in a cloud-based HIPAA compliant server (in a remote device of the healthcare professional). It is envisaged that a secure connection to the server for review of the image would be implemented in such instances to maintain confidentiality and security of the patient data, for example through use of a web portal where healthcare professionals can monitor patient disease trajectory based on changes of the eye image data over time.

Additional detail regarding the support extensions / arms 10 of the device 1, and how these components can contribute to stable positioning of the device 1 in relation to the subject’s face, will now be provided with reference to Figures 1A and 8. In the illustrated embodiment, a pair of support extensions 10 is provided. As may be seen, these support extensions 10 take the form of a pair of blades or plates which each extend from an uppermost portion of the upper housing portion 2B in a diverging manner (thereby having a generally ‘V’-shaped morphology). Each blade terminates in curved topmost edges 10A which are arranged to contact / interface with the subject’s face.

As will be appreciated from the illustration of Figure 7, one of the blades (hereafter referred to as the ‘upper blade’) is arranged to contact an upper portion of the subject’s face (in this example, the supraorbital ridge); whilst the other blade (hereafter referred to as the ‘lower blade’) is arranged to contact a lower portion of the subject’s face (in this example, the subject’s lower eyelid). This configuration enables the device 1 to be positioned appropriately above the subject’s eye. As is also shown in Figure 7, the upper blade is shorter than the lower blade (e.g., by a few tens of millimetres, such as 15 millimetres); this difference in length between the pair of blades causes the device 1 to assume a naturally tilted orientation relative to the subject’s face when the device 1 is positioned for the two blades to contact the respective portions of the subject’s face. The exact degree of angular tilt for the device (i.e., the angle between the central axis Έ’ of the subject’s eye and a central axis Ό’ running through the fluid reservoir 4 of the device 1) may vary depending on the exact dimensions of the device 1 , the reservoir 4, the support extensions 10 and the subject’s face. However, this angular tilt will be between around 45 to 55 degrees (for example, 50 degrees or so). This angular tilt is useful for the dispensing of fluid from the reservoir 4 as the exit port4A (e.g., the eye drop bottle tip) will be angled relative to the subject’s eye; it also ensures that the sensor unit 8 and any other eye-monitoring components of the device 1 can be appropriately oriented to maintain a good line-of-sight view of the subject’s eye during the drop dispensing process.

Furthermore, the configuration of the support extensions 10 (and more particularly their diverging arrangement along with the curved edges), when first applied to the lower eyelid and then supported onto the supra-orbital ridge, can be used to increase the exposed eye and surface area for successful drop instillation by distracting the lower eyelid.

Alternative arrangements are also envisaged in which the lower blade / support extension 10 could instead be designed to rotate and sit upon the nasal bridge to avoid contact with the soft tissue of the subject’s eyelid. This alternative arrangement is illustrated in Figure 9, which shows a device T that contains corresponding components to the device 1 illustrated in Figures 1A and 1 B, and which functions in substantially the same manner as that described above in relation to the device 1. As shown in Figure 9, the pair of support extensions 10 have been rotated by 90 degrees (relative to the device 1 shown in Figure 8 for example), such that the support extensions 10 interface with portions of the subject’s face (horizontally / laterally) on either side of the subject’s eye, rather than vertically above and below the subject’s eye. In this alternative arrangement, the sensor unit 8 and its associated support extension 10 (which, in the device 1 of Figure 8 would have rested below the subject’s eye) now rest against the subject’s nasal bridge when in use. This enables the sensor unit 8 to still be appropriately positioned and oriented relative to the subject’s eye to maintain a good line-of-sight view of the subject’s eye during the drop dispensing process. Alternative support extension arrangements are also envisaged and will be discussed in more detail subsequently with reference to Figures 11A to 11C. Additional or alternative modifications may be made to the device 1 and method embodiments described herein which would be encompassed by the scope of this disclosure.

For example, it is envisaged that in some embodiments, the fixation source 34 may also provide additional functionality as a visual cue for user control of guiding parameters and device functionalities. In such embodiments, the fixation source 34 may be implemented in combination with a push button (not shown) capable of custom gesture detection, and causing the fixation source 34 and device 1 to operate in a customised user-specific manner. In this manner, the fixation source could provide varying illumination characteristics as feedback to the user following their customisation / set-up of the device 1 functionality. For example, a long press of this button could result in the device 1 accepting user input of a desired number of drops when activating the drop dispensing mechanism of the device. To imply the device 1 has entered this state, the fixation source 34 could then begin flashing and upon discrete button presses, the fixation source 34 could flash / blink to register the number of requested drops. In a similar vein, other device functionalities could also be modified via the button press and fixation source 34 illumination feedback / output, in the absence of a conventional screen display.

Additionally or alternatively, it is envisaged that in some embodiments, the fluid delivery mechanism could be configured to apply the compressive forces to a compliant base wall 4D of the reservoir 4, in addition, or as an alternative, to a lateral side wall 4B, 4C. Utilising this mechanism, the fluid can be dispensed from the reservoir 4 without the need for any specific lateral supports (such as support 20) provided proximal to the opposing side wall of the reservoir to the mechanism. Rather, only a restriction to vertical translation of the reservoir would be required, which could be provided at least partially by the retaining plate 28. This mechanism for applying pressure to the fluid in the reservoir 4 is particularly suitable where the reservoir 4 corresponds to a conventional eye dropper bottle, due to their narrower necks against which rigid constriction can be applied.

Figures 10A to 10D show different aspects of a device T where some compressive forces are applied to the base wall 4D of the reservoir 4. The device T shown in these figures also comprises a housing 2’ configured to retain a fluid reservoir 4, and a fluid delivery mechanism 6’ that can apply controllable pressure to the reservoir 4 to dispense the fluid into the subject’s eye. The device T also comprises a sensor unit 8 and support extensions 10 which provide functionality corresponding to that described earlier in relation to the device 1 of Figure 1A. The main principles by which the two devices 1, T operate are similar (and where appropriate like reference numerals have been used in both embodiments to refer to corresponding components and their functionalities); the main differences between these two devices 1, T are set out below.

To begin with, the fluid delivery mechanism 6’ comprises a laterally-extending compression element 14’ positioned in proximity to one of the side walls 4B of the reservoir 4 (where previously the fluid delivery mechanism 6 in the device 1 of Figure 1A comprised a rotatable cam 14). As shown in Figure 10C, the compression element 14’ is connected to a motor 16’ which drives lateral translational movement of the compression element 14’ relative to the reservoir side wall 4B. Similarly to the device 1 of Figure 1A, an axial force is hence applied to the side wall 4B of the reservoir by the compression element 14’, compressing the side wall 4B and reducing the internal space within the reservoir 4, thereby causing fluid to be dispensed. The compression element 14’ may take various forms - e.g., a motor-driven linear actuator, or a motor-driven lead screw mechanism, where rotational motion of the motor 16’ is converted into (lateral) translation of the compression element 14’. As shown in Figures 10A and 10C, the compression element 14’ is contained within a protrusion 2D’ which is formed integrally with, or connected to, the main body 2A’ of the device housing 2’ and extends outwards from the housing 2’. This configuration optimises the size and shape of the housing 2’ - minimising the amount of housing that is required to contain the reservoir 4 and the fluid delivery mechanism 6’, whilst also providing a handle for the subject to hold the device T.

Additionally, an alternative adjustment mechanism 22’ is provided which is configured to adjust a substantially vertical dimension of the housing 2’ (i.e., adjustment of dimensions along the axis from which fluid is dispensed), rather than the lateral dimension of the housing (as was the case for the adjustment mechanism 22 in the device 1 of Figure 1A). Specifically, the adjustment mechanism 22’ comprises an adjustable lead screw 22A’ and a base platform 22B’ that are connected to (a base wall of) the device housing 2’. The base wall 4D of the reservoir is arranged to rest upon the base platform 22B’, and adjustment (rotation) of the lead screw 22A’ translates the base platform 22B’ in a vertical direction (thereby also translating the reservoir 4 upwards within the housing 2’). This adjustment is shown as being able to be effected manually, but a motorised adjustment mechanism could alternatively be provided. The adjustment mechanism 22’ can securely accommodate differently sized reservoirs within the same housing 2’, and also minimise the amount of movement of the reservoir 4 within the housing 2’ when the fluid delivery mechanism 6’ is activated. The flexibility of the device T for use with off-the-shelf or with bespoke bottles of fluid is hence increased. It will be appreciated that the adjustment mechanism 22’ may provide at least some fluid delivery functionality, either in combination with lateral forces applied by the fluid delivery mechanism 6’ or by functioning as the primary fluid delivery mechanism.

The device housing 2’ also comprises an internal retainer 28’ that is configured to retain and support the reservoir 4. This retainer 28’ is provided in an upper portion 2B’ of the housing 2’ and is shaped to narrow / taper in an axially-upwards direction; as shown in Figure 10D, the retainer 28’ may take the form of a curved tapering element (e.g., a part conical, or frusto- conical, shape). This configuration is particularly useful where the reservoir 4 used is a typical (multi-use) eye drop bottle (which tapers towards the exit port 4A), as the retainer 28’ thereby provides a complementary ‘female’ portion of the housing 2’ that is configured to receive the upper ‘male’ end of the reservoir bottle. The adjustment mechanism 22’ may move the reservoir 4 within the housing such that the tapered end of the reservoir rests against and interfaces in a complementary manner with the inner surface of the retainer 28’. Axial (vertical) movement of the reservoir 4 within the housing 2’ is hence minimised, and differently shaped reservoirs 4 can be easily accommodated.

An alternative method for eye state detection is also envisaged for implementation in certain instances. In this alternative method, instead of carrying out processing and analysis of the information contained within images obtained by an image capture device 8A such as a camera, reflectance-based detection can be implemented. More particularly, this would be carried out utilising a light emitter (not shown, but envisaged to be located in a corresponding position to the sensor unit 8 on one of the support extensions 10), and a light detector (also not shown, but envisaged to be located on an opposite one of the support extensions 10 from the location of the light emitter). The light emitter is configured to project incident light (e.g., visible or infrared wavelengths) onto the subject’s eye; this light will then be reflected from the subject’s eye onto the light detector (e.g., a wavelength-specific sensor). The tear-film of the subject’s cornea will have higher reflective surface properties than the soft-tissue of the subject’s eyelid, and hence a higher intensity of light detected by the light detector can be used as an indication of the subject’s eye being in an ‘open’ state; whilst a decreased light intensity would correspond to the subject’s eye being in a ‘closed’ state.

Another alternative implementation example is envisaged, the details of which are illustrated in Figures 11A to 11C. The device 1” shown therein also shares various features in common with the previous described devices 1, T - for example, the housing 2” (similar to housing 2’), reservoir 4, fluid delivery mechanism 6” and sensor unit 8. It will be appreciated that different combinations of the aspects of the previously described devices 1, 1’ can be incorporated into the device 1” of Figures 11 A to 11C - for example, the fluid delivery mechanism 6” could take the form of a compression element 14’ or of a rotatable cam 14 (or any other alternative); and the adjustment mechanism 22’ may be additionally incorporated into the device 1”.

The main features of the Figures 11A to 11C device 1” that will be highlighted here relate to the manner in which the housing 2” and the reservoir 4 interface with one another, as well as the way in which the device 1” may interface with the subject’s face. To begin with, as shown in Figures 11A and 11 B, the device 1” comprises a removable reservoir retainer 50 that interfaces with the reservoir 4 and also with the device housing 2”, allowing the reservoir 4 to be easily removed from (and reinserted into) the housing 2”. As will be appreciated from the illustrations, the specific form of the retainer 50 shown here is particularly appropriate where the reservoir is a (multi-use) fluid bottle (e.g., an off-the-shelf eye drop bottle), and allows the reservoir to be easily changed and/or refilled as the fluid runs out over long term use of the device 1”.

The illustrated retainer 50 takes the form of a clip that is configured to attach to, and interface fit with, the reservoir bottle, and comprises a (part) circular ring element 52 that is configured to attach to (e.g., snap-fit) and at least partially encircle the neck of the reservoir bottle. The retainer 50 may be inserted into an opening 2C” in a side of the housing 2” (thereby substantially completing the outer wall of the housing 2”); in order to do so, the retainer 50 further comprises a housing interface element 54 configured for insertion into the housing opening 2C”, so as to reliably locate the attached reservoir 4 in the appropriate location (relative to the sensor unit 8 and fluid delivery mechanism 6”) for fluid dispensing to occur.

The retainer 50 comprises a locking mechanism 56 configured to securely maintain the retainer 50 in its desired position. In the illustrated embodiment of Figures 11A and 11 B, the locking mechanism 56 comprises a pair of laterally translatable tabs 56A, 56B that can be extended / translated laterally to interface with complementary slots / openings (not shown) provided on corresponding, adjacent portions of the housing 2”; the locking mechanism 56 also comprises an axially (vertically) translatable tab 56C that can be extended / translated axially to interface with a complementary slot on an adjacent portion of the housing 2”. This configuration increases the flexibility and reusability of the device 1” with multiple reservoirs 4, whilst nevertheless ensuring secure and accurate retention of the reservoir 4. The tabs 56A, 56B, 56C may take the form of spring-loaded reverse action clip mechanisms. The retainer also comprises a protruding handle 58 that can be used to manipulate the retainer 50 and its attached reservoir 4. Alternative configurations are also contemplated, for example, where single-use eye drop containers are utilised, the retainer 50 may comprise a slot (as such containers do not have a well-defined neck portion for attachment of the clip element 52).

The supports 10” that allow the device 1” of Figures 11A and 11C to interface with the subject’s face during use also differ from those of the device 1 shown in Figures 1A and 8. The device 1” comprises a first support extension arm 101 extending upwardly from the device housing 2”, and which terminates in a curved topmost edge 10A” arranged to contact the subject’s face during use, specifically an upper portion thereof (e.g., the supra-orbital ridge). However, instead of having a second (lower) support extension arm, the device 1” comprises a ring-shaped extension 102 provided upon and substantially encircling the rim 2E” of the housing 2”. When in use and placed against the subject’s face, the ring extension 102 is configured to rest against the portion of the subject’s face below their eye (e.g., the infra-orbital ridge), thereby providing support functionality as well as aiding in retraction of the subject’s lower eyelid. T ogether these support extensions 101 , 102 improve the device stability during fluid dispensing and also increase the eye surface for instillation; as a result, increased likelihood of successful dispensing is achieved. Additionally, as may be seen from the figures, the interior cavity (not shown) of the device 2” accommodating the reservoir bottle, having an internal boundary at an uppermost portion of the device 2” defined by the support extensions 101 , 102, has dimensions large enough to enable re-capping of the reservoir bottle to maintain sterility of its contents, and to also enable a reservoir bottle to be (semi-)permanently stored within the device housing 2” (as secured by the retainer 50).

As was the case with the device 1 of Figure 8, the sensor unit in Figures 11A and 11 C is positioned on the ‘upper’ support extension arm 101”. However, in this case, the support extension 101 also extends axially (downwards) within and below the rim 2E” at the uppermost portion of the device housing 2”. The sensor unit 8 is provided on a lower portion of the support extension 101, such that the sensor unit 8 is at least partially located below the rim 2E” of, and hence within the internal space of, the housing 2”. The sensor unit 8 is therefore accommodated largely within the housing body of the device 1”, thereby protecting the sensor unit 8 and increasing the robustness of the device 1”, whilst also improving the compactness of the design and reducing the size of the device 1”.