CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 63/308,169, filed Feb. 9, 2022, and is related to U.S. patent application Ser. No. 17/345,419, filed Jun. 11, 2021, each of which is incorporated by reference herein in its entirety.

FIELD

The present technology relates to systems and methods for retinal stimulation by light, collecting retinal signal data and/or processing retinal signal data.

BACKGROUND

A signal is a function that conveys information generally about the behavior of a physical or physiological system, or the attributes of some phenomenon. Retinal signal data, such as electroretinograms (ERG) data, may be collected for analysis. The retinal signal data may be collected using sensors such as one or more electrodes attached to an individual. The electrodes may capture electrical signals. The electrical signals originate from specific cells located in the retina. The electrical signals are triggered by light stimulation and are responsive to the light stimulation. A light stimulator may be used to trigger the electrical signals. ERG are commonly recorded in ophthalmology and optometry applications to assess retinal function.

During the retinal stimulation and capture of retinal signal data, various factors may affect the retinal signal data, such as movement of the eye and the eye lids, intensity and wavelength of the light stimulation, intensity and wavelength of the background light, light intensity waveform, duration and sequence of light stimulation, areas of the retina illuminated, time during which the retinal signal data is collected, and/or other characteristics of the circuit collecting the electrical signals or the individual. It is an object of the present technology to ameliorate at least some of the limitations present in the prior art.

SUMMARY

Embodiments of the present technology have been developed based on developers' appreciation of certain shortcomings associated with existing systems for collecting retinal signal data. The characteristics of the retinal signal data elicited by light stimulation is directly dependent upon the characteristics of the light stimulation. The characteristics of the light stimulation triggering the retinal signal data may be collected and used during analysis of the retinal signal data. This collected light stimulation data may be used to extract biomarkers and/or collect relevant descriptors (biosignature) from the retinal signal data. Furthermore, the light stimulation characteristics may be considered when analysing retinal signal data, as co-variables of that retinal signal data.

Existing systems for collecting retinal signal data might not collect data about the individual that may be relevant to the retinal signal data, such as eye position, pupil size, pupil area, light beam illumination axis (optical axis), area of the retina that has been stimulated, and/or other data about the individual. Indeed, the amount of light reaching the retina and the area of the retina that has been illuminated, is not only dependent upon the pupil area, but also upon the beam illumination axis (i.e. optical axis) and the eye movement (rotation) around this axis. Existing systems for collecting retinal signal data might not collect data about the system that may impact the retinal signal data, such as timing information, angle at which the light reaches the retina, light intensity, light spectrum, light intensity waveform, duration and sequence of light stimulation, and/or other data about the system triggering the retinal signal and/or collecting the data. Rather than measuring this data, existing systems may simply record the intended values contained in the settings, but not record and/or control continuously in real time the actual values. For various reasons, such as design and manufacturing issues, component tolerances, components wearing out, changes in calibration, absence of real time measurement and/or control, etc., the set values and actual measured values may differ.

The system described herein may allow for more precise control of various parameters during light stimulation of the retina and subsequent collection of the retinal signal data. It may also allow for continuous adjustment of those values depending upon the measured actual values. This may lead to improvements in the collected retinal signal data, such as a reduction in artifacts, improvement in the relevancy of collected data, more precision in the collected retinal signal data, collection of information directly impacting on the retinal signal data which may be used to analyze the retinal signal data, and/or other improvements.

The retinal signal data may include artifacts. These artifacts may impede further analysis of the retinal signal data. These artifacts might also be transient or occurring within a very short period of time, and therefore difficult or impossible to detect without continuous monitoring. It may be preferable to use retinal signal data that does not contain artifacts and/or that contains less artifacts. A dynamic resistance of a circuit collecting the retinal signal data, such as the impedance of the circuit, may be used to determine whether the retinal signal data contains artifacts. U.S. patent application Ser. No. 17/345,419, incorporated herein by reference in its entirety, describes methods and systems that may be used to remove artifacts from retinal signal data and/or reduce the impact of artifacts on the retinal signal data.

Embodiments of the present technology have been developed based on the developers' observation that data obtained in electroretinograms (ERG) may provide some insight into determining conditions, such as medical conditions. However, existing methods to collect and analyse electroretinograms (ERG) can only collect and analyse a limited volume of information from the captured electrical signals. It was found that expansion of the nature and the volume of information collected regarding retinal response to light stimulation allowed generating retinal signal data with a higher density of information, a higher volume of information, and/or additional types of information. This method to collect retinal signal data with higher density of information enables a multimodal mapping of the electrical signals and/or other data and allows the detection of additional information in the multimodal mapping specific to certain conditions. The multimodal mapping may include multiple parameters of the retinal signal data, such as time, frequency, light stimulation parameters, areas of the retina impacted by the light stimulation, and/or any other parameters.

Several types of information or data which have a direct impact on the retinal signals are not collected during conventional ERG recording. However, as developers have noted that the triggered electrical signals may be directly dependent on those parameters, embodiments of the present technology include real-time measurement of any one or more of: light spectrum, light intensity, form of the light stimulation signal, illuminated area, pupil size, pupil position, and/or impedance of the circuit collecting the electrical signals. The system described herein may be configured to measure some or all of these parameters.

Embodiments of the present technology form the basis for collecting and/or processing of retinal signal data which has more volume of information, more density of information and/or additional types of information detail compared to conventional ERG data. The number and/or range of light intensities of the light stimulation may be increased. This retinal signal data allows, in certain embodiments, the mathematical modeling of datasets containing a multiplicity of information, and the ability to identify biomarkers and/or biosignatures in the retinal signal data using for example a specific pattern of the retinal signal detected in certain pathological conditions. Certain, non-essential, embodiments of the present technology also provide methods for collecting the retinal signal data which has more volume of information, more density of information and/or additional types of information compared to conventional ERG data.

In some instances, the retinal signal data, or any other signal data associated with light stimulation may contain artifacts. The artifacts may include distorted signals, interferences, and/or any other type of artifacts. The artifacts may occur through one or more of: signals not originating from the retina being inadvertently captured, shifts in the electrode positioning, changes in the ground or reference electrode contact, photomyoclonic reflex, eye lid blinks, ocular movements, and/or external electrical interferences. These artifacts may restrain further analysis of the retinal signal data, or skew the further analysis. It would be beneficial if these artifacts could be removed, compensated for, or prevented.

Parameters of the electrical signals emitted by an individual may be measured, such as voltage, current, impedance, conductance, and/or any other parameters, such as other parameters related to the circuit collecting the retinal signal. The parameters may be measured continuously over a period of time. During the period of time, the individual may be exposed to a flash of light. Parameters of the flash of light may be measured, such as the light intensity, spectrum, timing and form of the flash, and/or any other parameters of the flash of light. Attributes of the individual may be measured before, during, and/or after the flash of light, such as pupil size, and/or any other attributes of the individual that may affect the retinal signal data.

The data collected prior to the flash of light may be used as calibration data. The data collected after the flash of light may be retinal signal data. Baseline parameters of the electrical circuit capturing the electrical signals may be determined using the calibration data, such as a baseline voltage, baseline current, baseline impedance, and/or any other parameters. A threshold impedance may be determined based on the baseline impedance. The retinal signal data may be compared to the threshold impedance. If the impedance of the circuit during collection of the retinal signal data surpasses the threshold impedance, the retinal signal data may be determined to have artifacts or other events which may be attended to and/or corrected. An amount of change of the impedance of the circuit and/or a rate of change of the impedance may also be determined to indicate a presence of an artifact.

In conventional ERG, a flash of light having the same parameters may be repeated multiple times, such as ten times. The electrical signals responsive to the flash may be collected each time. Data regarding those electrical signals may be averaged, such as by determining an average voltage of the electrical signals. The same flash of light (i.e. a flash of light having the same flash parameters) may be repeated to reduce the impact of artifacts on the collected data. For example if the flash of light is repeated ten times, and artifacts occur in the electrical signals responsive to one of those flashes, the impact of those artifacts will be reduced by combining the data collected after that flash of light with the data collected after the other nine flashes of light.

Artifacts may be detected through other means, such as by monitoring the dynamic resistance of the collecting circuit, such as the impedance, admittance, and/or susceptance of the circuit collecting the electrical signals. Rather than repeating the same flash of light multiple times, retinal signal data responsive to a single flash of light and/or a reduced number of flashes of light may be collected. The retinal signal data may be analyzed to determine whether the retinal signal data contains artifacts. For example the impedance of the retinal signal data may be compared to a threshold impedance. If the impedance of the retinal signal data does not exceed the threshold impedance, the retinal signal data may be determined not to contain artifacts. The retinal signal data may then be stored. In this manner, retinal signal data may be collected without repeating the flash of light having the same parameters and/or the amount of times that a flash of light having the same parameters is repeated may be reduced. This may reduce the amount of time used for collecting the retinal signal data and/or decrease the impact of artifacts on the retinal signal data.

In certain embodiments, a more efficient processing of retinal signal data is possible compared to ERG data collected using conventional methods. The advantage of retinal signal data as compared to the conventional ERG data, is to benefit from a larger amount of information related to the electrical signals. This additional data may be used to identify artifacts in the retinal signal data, remove the artifacts in the retinal signal data, reduce the artifacts in the retinal signal data, and/or otherwise compensate for the artifacts in the retinal signal data.

In certain embodiments, artifacts are detected and/or removed from the retinal signal data. The artifacts may be detected and/or removed after the collection of retinal signal data is complete and/or in real-time during the collection of the retinal signal data. If the artifacts are detected during collection of the retinal signal data, an indication may be displayed to an operator that artifacts have been detected. The parameters of the flash of light that was triggered prior to the retinal signal data with artifacts may be determined and a flash of light having the same parameters may be triggered. Retinal signal data occurring after that flash of light may be captured and/or stored for further analysis.

As described above, parameters of the light that the individual is exposed to, either directly (light stimulation) or indirectly (background light), may be collected, such as light spectrum, intensity, form and sequence. If the measured light spectrum, intensity, form or sequence does not match the light spectrum, intensity, form or sequence that was specified, the settings may be adjusted and a flash of light with the new settings may be triggered in order to collect retinal signal data that is generated in response to the desired light spectrum, intensity, form and/or sequence.

According to a first broad aspect of the present technology, there is provided an apparatus for retinal stimulation, the apparatus comprising a housing supporting: one or more light sources configured to expose a retina of an eye of an individual to a flash of light; a spectrometer configured to record a light spectrum and an intensity of the flash of light; and a camera configured to capture image data of the eye while exposed to the flash of light.

In some implementations of the apparatus, the apparatus is a head-worn apparatus to be worn on a head of the individual.

In some implementations of the apparatus, the apparatus comprises an eye shade for enclosing the eye of the individual, and the eye shade is configured to block external light from entering the eye of the individual.

In some implementations of the apparatus, the apparatus further comprises a light reflector configured to direct light from the one or more light sources towards the eye of the individual.

In some implementations of the apparatus, the apparatus further comprises a controller communicatively coupled to the one or more light sources, the spectrometer and the camera, and the controller is configured to adjust a parameter of the one or more light sources based on data from the spectrometer.

In some implementations of the apparatus, the controller comprises a control circuit supported by the housing and configured to receive data from the spectrometer.

In some implementations of the apparatus, the camera is in communication with the controller, and the controller executes instructions that determine, based on data received from the camera: a position of the eye of the individual, a pupil size of the eye of the individual, or a shape of the eye of the individual.

In some implementations of the apparatus, the apparatus further comprises one or more electrodes attachable to the individual and configured to collect electrical signals from the individual.

In some implementations of the apparatus, the apparatus further comprises one or more electrodes attachable to the individual and configured to collect electrical signals from the individual, the one or more electrodes communicatively connectable to the controller, the controller being configured to receive electrical signal data from the electrodes.

In some implementations of the apparatus, the apparatus further comprises a battery for providing power to one or more of: the one or more light sources, the spectrometer, and the camera.

In some implementations of the apparatus, the apparatus further comprises a networking device.

In some implementations of the apparatus, the apparatus further comprises a safety module configured to monitor a temperature of the apparatus.

In some implementations of the apparatus, the apparatus further comprises one or more amplifiers and one or more filters.

In some implementations of the apparatus, the one or more light sources comprise a light emitting diode (LED).

In some implementations of the apparatus, the one or more light sources, the spectrometer and the camera define a first sub-system configured for retinal stimulation of a first eye of the individual, the apparatus further comprising a second sub-system configured for retinal stimulation for a second eye of the individual, the second sub-system comprising another set of light sources, spectrometer and camera.

According to another broad aspect of the present technology, there is provided a system for collecting retinal signal data, the system comprising: one or more light sources configured to expose a retina of an eye of an individual to a flash of light; a spectrometer configured to record a light spectrum and an intensity of the flash of light; and a controller communicatively coupled to one or more of: the one or more light sources, and the spectrometer, wherein the controller is configured to: adjust a parameter of the one or more light sources based on data from the spectrometer, expose the retina to an adjusted flash of light, and receive electrical signals produced by the retina of the individual in response to the adjusted flash of light.

In some implementations of the system, the controller comprises a processor of a computer system communicatively couplable with the one or more light sources and the spectrometer.

In some implementations of the system, the controller comprises a control circuit, the control circuit is communicatively coupled to the one or more light sources, and the control circuit is communicatively coupled to the spectrometer and configured to receive data from the spectrometer.

In some implementations of the system, the system further comprises a light reflector configured to direct light from the one or more light sources towards the eye of the individual, where the light reflector is spheroidal and includes an eye shade portion around a light outlet of the light reflector, the eye shade portion is configured to enclose the eye of the individual, and the eye shade portion is configured to minimize or block external light from entering a housing of the system.

In some implementations of the system, the system further comprises one or more electrodes attachable to the individual and which are communicatively couplable with the controller, and the electrodes are configured to collect the electrical signals produced by the retina of the individual.

In some implementations of the system, the system further comprises a battery for providing power to one or more of: the one or more light sources, and the spectrometer.

In some implementations of the system, the system further comprises a camera, the camera is in communication with the controller, and the controller is configured to execute instructions that determine, based on data received from the camera: a position of the eye of the individual, a pupil size of the eye of the individual, or a shape of the eye of the individual.

In some implementations of the system, the system further comprises a networking device, a safety module configured to monitor a temperature of the system, or one or more amplifiers and one or more filters.

In some implementations of the system, the system further comprises a housing, the housing is configured to support the one or more light sources and the spectrometer, the housing has a portion for enclosing the eye of the individual, and the housing has a wearable configuration.

In some implementations of the system, the housing comprises a helmet to be worn on a head of the individual, or eye wear configured to be worn over eyes.

In some implementations of the system, the helmet or the eye wear comprises one or more straps to secure the helmet or the eye wear to the individual.

In some implementations of the system, the one or more light sources comprise a light emitting diode (LED).

In some implementations of the system, the one or more light sources and the spectrometer define a first sub-system configured for retinal stimulation of a first eye of the individual, and the system further comprises a second sub-system configured for retinal stimulation of a second eye of the individual, the second sub-system comprising another set of light sources, and another spectrometer.

In some implementations of the system, the parameter comprises a wavelength of the one or more light sources or an intensity of the one or more light sources.

According to another broad aspect of the present technology, there is provided a method for collecting retinal signal data, the method configured to be executed by a processor of a system for collecting retinal signal data, the method comprising: causing one or more light sources to output a first flash of light at a selected wavelength and a selected intensity to an individual; receiving, from a spectrometer, a measured wavelength and a measured intensity of the first flash of light; determining that the measured wavelength and the measured intensity is not within a pre-determined tolerance of the selected wavelength and the selected intensity; determining, based on a difference between the selected wavelength and the measured wavelength, and based on a difference between the selected intensity and the measured intensity, parameters for a second flash of light; causing the one or more light sources to output the second flash of light based on the parameters; and receiving, from a sensor associated with the individual, retinal signal data of the individual responsive to the second flash of light.

In some implementations of the method, the method further comprises receiving, from the sensor, retinal signal data of the individual responsive to the first flash of light.

In some implementations of the method, the one or more light sources and the spectrometer are integrated in a housing of an apparatus, and the apparatus further comprises a camera.

In some implementations of the method, the method further comprises receiving, from the camera, data regarding a pupil of the individual; and determining, based on the data from the camera, a pupil size or shape when viewed from a fixed point of the individual that was exposed to the second flash of light.

In some implementations of the method, the method further comprises determining, based on the data from the camera, an area of the retina of the individual that was exposed to the second flash of light.

In some implementations of the method, the method further comprises adjusting, based on the pupil size and shape, the retinal signal data, or determining, based on the pupil size and shape, to re-record the retinal signal data.

In some implementations of the method, the method further comprises receiving calibration data corresponding to the individual; determining, based on the calibration data, a threshold impedance of a circuit that collected the retinal signal data; determining that an impedance of the circuit has surpassed the threshold impedance; and after determining that the impedance of the circuit has surpassed the threshold impedance, re-recording the retinal signal data.

According to another broad aspect of the present technology, there is provided a system for collecting retinal signal data, the system comprising: one or more light sources configured to expose a retina of an eye of an individual to flashes of light; and a spectrometer configured to record a light spectrum and an intensity of the flashes of light, wherein the system is configured to collect electrical signals produced by the retina of the individual in response to the flash of light; and at least one processor and memory storing executable instructions which, when executed by the at least one processor, cause the system to: output, by the one or more light sources, a first flash of light at a selected wavelength and a selected intensity to the individual; receive, from the spectrometer, a measured wavelength and a measured intensity of the first flash of light; determine that the measured wavelength and the measured intensity is not within a pre-determined tolerance of the selected wavelength and the selected intensity; determine, based on a difference between the selected wavelength and the measured wavelength, and based on a difference between the selected intensity and the measured intensity, parameters for a second flash of light; cause the one or more light sources to output the second flash of light based on the parameters; and receive, from an electrode associated with the individual, retinal signal data of the individual responsive to the second flash of light.

In some implementations of the system, the retinal signal data comprises data from the spectrometer.

In some implementations of the system, the instructions further cause the system to: receive calibration data corresponding to the individual; determine, based on the calibration data, a threshold impedance of a circuit that collected the retinal signal data; determine that an impedance of the circuit has surpassed the threshold impedance; and after determining that the impedance of the circuit has surpassed the threshold impedance, re-record the retinal signal data.

In some implementations of the system, the system further comprises a camera, and the instructions further cause the system to determine, based on the data from the camera, a pupil size and shape of the individual that was exposed to the second flash of light.

In some implementations of the system, the instructions further cause the system to receive, from the electrode, retinal signal data of the individual responsive to the first flash of light.

According to another broad aspect of the present technology, there is provided an apparatus for retinal stimulation, the apparatus comprising a housing supporting: a first light source configured to expose a retina of a left eye of an individual to a first flash of light; a second light source configured to expose a retina of a right eye of the individual to a second flash of light; a first spectrometer configured to record a light spectrum and an intensity of the first flash of light from the first light source; a second spectrometer configured to record a light spectrum and an intensity of the second flash of light from the second light source; a first camera configured to capture image data of the left eye while exposed to the first flash of light; and a second camera configured to capture image data of the right eye while exposed to the second flash of light.

In some implementations of the apparatus, the first light source and the second light source are configured to output the first flash of light and the second flash of light simultaneously.

In some implementations of the apparatus, the apparatus further comprises a controller communicatively coupled to the first light source and the first spectrometer, wherein the controller is configured to adjust a wavelength or an intensity of the first light source based on data from the first spectrometer.

In some implementations of the apparatus, the controller is configured to adjust a wavelength or intensity of the second light source based on data from the second spectrometer.

In some implementations of the apparatus, the apparatus further comprises a controller communicatively coupled to the first light source and the first camera, and the controller is configured to determine: a distance between the first camera and an iris of the left eye, a distance between the first light source and the iris of the left eye, a pupil size of the left eye, a pupil shape of the left eye, or an eye position of the left eye.

In some implementations of the apparatus, the apparatus further comprises a controller communicatively coupled to the second light source and the second camera, and the controller is configured to determine: a distance between the second camera and an iris of the right eye, a distance between the second light source and the iris of the right eye, a pupil size of the right eye, a pupil shape of the right eye, or an eye position of the right eye.

According to another broad aspect of the present technology, there is provided a method for collecting retinal signal data, the method configured to be executed by a processor of a system for collecting retinal signal data, the method comprising: causing one or more light sources to output a flash of light at a selected wavelength and a selected intensity to an individual; receiving, from a camera, an image of an eye of the individual; and determining, based on the image, an area of a retina of the eye that was exposed to the flash of light.

In some implementations of the method, the method further comprises determining, based on the image, a distance between the camera and an iris of the eye, and wherein determining the area of the retina comprises determining, based on the distance between the camera and the iris, the area of the retina that was exposed to the flash of light.

In some implementations of the method, the method further comprises determining, based on the image, a distance between the one or more light sources and an iris of the eye, and determining the area of the retina by determining, based on the distance between the one or more light sources and the iris, the area of the retina that was exposed to the flash of light.

In some implementations of the method, the method further comprises determining, based on the image, a pupil size, or shape, or area of the eye, and determining the area of the retina by determining, based on the pupil size, or shape, or area, the area of the retina that was exposed to the flash of light.

In some implementations of the method, the method further comprises determining, based on the image, a position of the eye, and determining the area of the retina by determining, based on the position of the eye, the area of the retina that was exposed to the flash of light.

According to another broad aspect of the present technology, there is provided an apparatus for retinal stimulation, the apparatus comprising a housing supporting: one or more light sources configured to expose a retina of an eye of an individual to a flash of light; a spectrometer configured to record a light spectrum and an intensity of the flash of light; and a camera configured to capture image data of the eye while exposed to the flash of light.

In some implementations of the apparatus, the apparatus is a head-worn apparatus to be worn on a head of the individual.

In some implementations of the apparatus, the apparatus comprises an eye shade for enclosing the eye of the individual.

In some implementations of the apparatus, the eye shade is configured to block external light from entering the eye of the individual.

In some implementations of the apparatus, the apparatus further comprises a light reflector configured to direct light from the one or more light sources towards the eye of the individual.

In some implementations of the apparatus, the apparatus further comprises a light at the bottom of the light reflector for the subject to fix the gaze and ensure the vision axis is centered onto the aperture of the light reflector.

In some implementations of the apparatus, the apparatus further comprises a photometer coupled to the one or more light sources, the spectrometer and the camera, wherein the photometer is configured to adjust a parameter of the one or more light sources based on data from the photometer.

In some implementations of the apparatus, the apparatus further comprises a controller communicatively coupled to the one or more light sources, the spectrometer and the camera, wherein the controller is configured to adjust a parameter of the one or more light sources based on data from the spectrometer or the photometer.

In some implementations of the apparatus, the controller comprises a control circuit supported by the housing and configured to receive data from the spectrometer.

In some implementations of the apparatus, the camera is in communication with the controller, and wherein the controller executes instructions that determine, based on data received from the camera, a position of the eye of the individual or a pupil size of the eye of the individual.