WO2025109221A1

WO2025109221A1 - Method, computer program and system for adaptive sampling of a visual field of a person

Info

Publication number: WO2025109221A1
Application number: PCT/EP2024/083484
Authority: WO
Inventors: Dominik BRÜGGER; Mathias ABEGG
Original assignee: Machinemd Ag
Current assignee: Machinemd Ag
Priority date: 2023-11-24
Filing date: 2024-11-25
Publication date: 2025-05-30
Anticipated expiration: 2026-05-24

Abstract

The invention relates to a method, particularly a computer-implemented method, for adaptive sampling of a visual field (1) of a person, wherein the method comprises the following steps: in a first measurement trial, exposing at least one eye of the person to a first optical stimulus (11) in the visual field (1) of the person, wherein the first optical stimulus (11) is displayed subsequently at a plurality of positions of a first plurality of positions in the visual field (1), and detecting for at least some positions of the first plurality of positions, particularly for all positions of the first plurality of positions, an eye reaction of the person in response to a positional change of the first optical stimulus (11) between two subsequently displayed positions of the first plurality of positions, wherein the eye reaction is selected from one or more of a group consisting of: a change in size of a pupil and/or a saccade (30), in a second measurement trial, exposing the at least one eye of the person to a second optical stimulus (12) in the visual field (1) of the person, wherein the second optical stimulus (12) is displayed subsequently at a second plurality of positions in the visual field (1), wherein the positions of the second plurality are located closer to positions of the first measurement trial that are associated with a smaller change in size of the pupil and/or lower saccadic efficiency, particularly wherein a lower saccadic efficiency is associated to longer saccadic latencies and/or lower gaze position accuracies of the person in response to positional changes of the first optical stimulus (11) than positions of the first measurement trial that are associated with a larger change in size of the pupil and/or larger saccadic efficiency, particularly wherein a larger saccadic efficiency is associated to shorter saccadic latencies and/or higher gaze position accuracies of the person in response to positional changes of the first optical stimulus (11), and detecting the eye reaction of the person in response to a positional change of the second optical stimulus (12) between positions of the second plurality of positions, and thereby adaptively sampling the visual field (1) of the person based on the detected eye reactions. The invention further relates to a computer program for adaptive sampling of a visual field (1) of a person as well as a system (100) for adaptive sampling of a visual field (1) of a person.

Description

Method, computer program and system for adaptive sampling of a visual field of a person

Description:

The present invention relates to a method, particularly a computer-implemented method, for adaptive sampling of a visual field of a person, a computer program for adaptive sampling of a visual field of a person as well as a system for adaptive sampling of a visual field of a person.

Visual field sampling plays a crucial role in diagnosing and monitoring various ocular and neurological disorders. Conventional visual field sampling is typically based on predefined measurement protocols, wherein optical stimuli are subsequently displayed in a predefined grid of positions in the visual field of the person. On the one hand, these conventional techniques suffer from redundant data collection from unaffected areas. On the other hand, predefined grids of positions restrict the resolution of the visual field sampling to the positions defined by the grid, such that potentially critical areas in the visual field that are not or only partially covered by the grid may be overlooked. This inefficiency prolongs testing durations, increases patient discomfort, and may lead to incomplete assessments. At the same time, such predefined measurement protocols are, as such, not tailored to the individual's visual capabilities, which neglects the circumstance that visual field defects are highly variable and can manifest differently from person to person. Consequently, these conventional visual field sampling approaches fail to provide a comprehensive and accurate understanding of the person's visual function.

Based on this, it is subject of the present invention to provide a method for adaptive sampling of a visual field of a person, a computer program for adaptive sampling of a visual field of a person and a system for adaptive sampling of a visual field of a person, which are improved with respect to the problems stated above.

This task is solved by a method for adaptive sampling of a visual field of a person with the features of claim 1 , a computer program for adaptive sampling of a visual field of a person according to claim 28 as well as a system for adaptive sampling of a visual field of a person according to claim 29.

Advantageous embodiments of the invention are given in the corresponding dependent claims and described in the following.

A first aspect of the invention relates to a method, particularly a computer-implemented method, for adaptive sampling of a visual field of a person. The method comprises the following steps: i) in a first measurement trial, exposing at least one eye of the person to a first optical stimulus in the visual field of the person, wherein the first optical stimulus is displayed subsequently at a plurality of positions of a first plurality of positions in the visual field, and detecting for at least some positions of the first plurality of positions, particularly for all positions of the first plurality of positions, an eye reaction of the person in response to a positional change of the first optical stimulus between two subsequently displayed positions of the first plurality of positions, wherein the eye reaction is selected from one or more of a group consisting of: a change in size of a pupil and/or a saccade, ii) in a second measurement trial, exposing the at least one eye of the person to a second optical stimulus in the visual field of the person, wherein the second optical stimulus is displayed subsequently at a second plurality of positions in the visual field, wherein positions of the second plurality are located closer to positions of the first measurement trial that are associated with a smaller change in size of the pupil and/or lower saccadic efficiency, particularly wherein a lower saccadic efficiency is associated to longer saccadic latencies and/or lower gaze position accuracies of the person in response to positional changes of the first optical stimulus than to positions of the first measurement trial that are associated with a larger change in size of the pupil and/or larger saccadic efficiency, particularly wherein a larger saccadic efficiency is associated to shorter saccadic latencies and/or higher gaze position accuracies of the person in response to positional changes of the first optical stimulus , and detecting the eye reaction of the person in response to a positional change of the second optical stimulus between positions of the second plurality of positions, and thereby adaptively sampling the visual field of the person based on the detected eye reactions.

The second measurement trial thus takes the detected eye reactions of the first measurement trial into account to adaptively adjust the spatial sampling of the visual field. This measure contributes to a substantial reduction of time needed to sample the visual field. In particular, in this way, the sampling is not performed repeatedly in regions that are known to be associated with eye reactions that point to a sufficient functionality of the eye, but adaptively adjusts to areas in the visual field that are associated with impairments.

The second measurement trial can be carried out immediately after the first measurement trial, particularly such that positional changes of the first optical stimulus between the first plurality of positions and a positional change of a position of the first optical stimulus to a position of the second optical stimulus associated with a transition from the first measurement trial to the second measurement trial occur according to the same criteria, particularly on the same or similar timescales. As such, the person may not perceive the first measurement trial and the second measurement trial to be distinct but to form a single, contiguous measurement protocol. Criteria for positional changes of the optical stimuli are disclosed herein.

In particular, at least some positions of the first plurality of positions are different from each other and at least some positions of the second plurality of positions are different from each other such that the eye reaction in response to positional changes between different positions can be detected.

In an embodiment of the invention, at most 40%, particularly at most 30%, more particularly at most 20% of the positions of the first plurality of positions are identical.

In another embodiment of the invention, the first plurality of positions is devoid of a reset position for resetting the gaze position upon saccades triggered by positional changes of the first optical stimulus.

According to another embodiment of the invention, the first plurality of positions is devoid of a reset position for resetting the gaze position upon saccades triggered by positional changes of the first optical stimulus.

In another embodiment of the invention, all positions of the first plurality of positions in the first measurement trial are different from each other.

The measures above regarding the first plurality of positions substantially speed up the sampling of large areas of the visual field compared to conventional methods that require a reset of the gaze position to a reset position upon individual saccades. This allows to scan large areas of the visual field in a short time during the first measurement trial, whereafter the second measurement trial may be initiated for adaptively sampling areas of the visual field that are associated with low eye reactions.

According to an embodiment of the invention, some of the positions of the second plurality of positions are reset positions for the resetting the gaze position upon saccades triggered by positional changes of the second optical stimulus. This measure allows for repeated saccades into areas of the visual field that are associated with low eye reactions. For example, every second position of the second plurality of positions is a reset position. The reset position can particularly be the origin of the visual field, i.e. the intersection between a horizontal and a vertical axis of the visual field in case of relaxed, forward-facing eyes. Particularly, some of the positions of the second plurality of positions are reset positions and: at most 40%, particularly at most 30%, more particularly at most 20% of the positions of the first plurality of positions are identical, the first plurality of positions is devoid of a reset position for resetting the gaze position upon saccades triggered by positional changes of the first optical stimulus, a majority of the positions, particularly 60%, more particularly 70% of the first plurality of positions are different from each other, or all positions of the first plurality of positions in the first measurement trial are different from each other.

This allows for a time-efficient sampling of large areas of the visual field in the first measurement trial, followed by a time-efficient sampling of specific areas in the visual field associated with low eye reactions in the second measurement trial.

Particularly, the first optical stimulus may correspond to the second optical stimulus in terms of its shape, size, color, and/or contrast in the visual field. In particular, the first optical stimulus and the second optical stimulus may be identical with regard to these terms.

Particularly, at least some positions of the first plurality of positions are identical or at least some positions of the second plurality of positions are identical. That is, during the first measurement trial, the first optical stimulus can be displayed at the same position multiple times. Similarly, during the second measurement trial, the second optical stimulus can be displayed at the same position multiple times. Moreover, at least some positions of the first plurality of positions are identical to at least some positions of the second plurality of positions. In other words, the second optical stimulus in the second measurement trial may be displayed at the same position as the first optical stimulus in the first measurement trial. By this measure, a degree of perception of the person may be assessed. If the detected changes in size of the pupil and/or the saccadic activity are inconsistent for positional changes to identical positions, i.e. the detected changes in size of the pupil and/or the saccadic activity show strong variations for positional changes to identical positions, the detected changes may point to a smaller degree of perception of the person than consistent detected changes in size of the pupil and/or saccadic activity, with smaller variations. Preferably, between display of the first or the second optical stimulus at identical positions, the first or the second optical stimulus is displayed at at least one different position, such that the person focuses in a different area of the visual field in between two positional changes to the same position, which allows to detect the eye reaction of the person in response to positional changes to the same position.

Alternatively, the second measurement trial is not carried out immediately after the first measurement trial. For example, the second measurement trial can be performed based on the eye reactions of the first measurement trials for example minutes, hours, days, months or years after the first measurement trial. As such, the first measurement trial may for example be associated with a first examination of the eye, wherein the first optical stimulus is applied with a flashlight. The eye reactions in response to positional changes of the first optical stimulus can be used for a later, second examination by means of the second measurement trial, wherein the second optical stimulus can be different from the first stimulus, for example wherein the second stimulus is applied via a head-mounted display to be worn by the person. In other words, the second measurement can generically use eye reactions determined in an earlier examination to adaptively sample areas in the visual field of the person which are associated with impairments discovered during the first measurement trial.

The first optical stimulus and the second optical stimulus can differ in their size, color and/or contrast in the visual field.

For example, the first optical stimulus and/or the second optical stimulus comprise or are symbol characters, letters, numbers, geometrical shapes. The first optical stimulus and/or the second optical stimulus can also be contrasty sections of an image, for example a bird in a panoramic view of a landscape.

Particularly, some of the positions of the first plurality of positions and/or the second plurality of positions are reset positions for the resetting the gaze position upon saccades triggered by positional changes of the first optical stimulus and/or the second optical stimulus. This measure allows to repeatedly arrange particularly the second optical stimulus at positions in areas of the visual field that are associated with smaller detected changes in size of the pupil and/or lower saccadic efficiency than positions of the first measurement trial that are associated with a larger change in size of the pupil and/or larger saccadic efficiency.

In another embodiment of the invention, during the first measurement trial and/or the second measurement trial, the first optical stimulus and/or the second optical stimulus are displayed in at least a portion of the visual field that comprises a luminance between 10 nit and 10.000 nit, particularly between 10 nit and 2.000 nit. 1 nit corresponds to a luminance of 1 cd/m². Corresponding luminance conditions in the visual field can be realized for example by means of a display, such as a head-mounted display. In the same fashion, a corresponding luminance of the respective optical stimulus can be realized within the visual field by means of said display. The luminance represents a parameter to vary a contrast of the optical stimulus in the portion of, particularly in the entire visual field, which allows to investigate the eye reactions not just in response to positional changes of the optical stimulus, but also for different luminances and hence contrasts of the optical stimulus in the visual field. Particularly, the luminance of the respective optical stimulus is more than 10 times, particularly more than 100 times lower than the luminance of the visual field, or the luminance of the respective optical stimulus is zero.

In particular, the luminance within the portion of the visual field, particularly within the entire visual field is constant during the first measurement trial and/or the second measurement trial. Particularly, the luminance within the portion of the visual field is additionally constant during at least one succeeding measurement trial as disclosed herein. This measure allows to investigate the eye reactions for consistent contrast conditions during the first measurement trial and/or the second measurement trial and particularly at least one succeeding measurement trial.

According to an embodiment of the invention, a plurality of sequences of measurement trials are performed, each sequence comprising at least the first and the second measurement trials, wherein in a second sequence of measurement trials, a contrast between at least a portion of the visual field, particularly the entire visual field, and the respective optical stimulus is adjusted based on detected eye reactions of the person during a first sequence comprised by the plurality sequences preceding the second sequence of measurement trials.

Particularly, a first sequence of measurement trials comprising the first measurement trial and the second measurement trial is performed, wherein the luminance of the portion of the visual field, particularly the entire visual field is constant at a first luminance during the first sequence of measurement trials. Upon the first sequence, a second sequence of measurement trials comprising the first measurement trial and the second measurement trial is performed, wherein the luminance of the portion of the visual field, particularly the entire visual field is constant at a second luminance, wherein the second luminance is different from the first luminance. In the same fashion, at least one further sequence with at least one further luminance can be performed.

In particular, for the first sequence, the luminance of the visual field can be set to a predefined threshold value at which the person is likely to correctly identify the optical stimulus. For example, for a 20 year old person, the threshold value can correspond to a sensitivity of around 32.8 dB on a decibel scale which is commonly used as a measure of sensitivity to light in clinical purposes, wherein 0 dB corresponds to a maximum luminance and increasing values on the scale correspond to decreasing luminances [Racette L, Fischer M, Bebie H, Hollo G, Johnson CA, Matsumoto C. VISUAL FIELD DIGEST. 8th ed. (Haag-Streit AG, Kdniz, Switzerland, ed.)]. Depending on whether the person correctly identifies a predefined number of optical stimuli positions during the first sequence, for example at least 90%, the luminance of the visual field can be adaptively adjusted. For instance, if the person correctly identifies the predefined number of optical stimuli positions during the first sequence, the luminance of the visual field may be decreased in the following second sequence, corresponding to a sensitivity above the threshold value, for example at 35 dB. If the person fails to correctly identify the predefined number of optical stimuli positions during the first sequence, the luminance in the following second sequence may be increased, corresponding to a sensitivity below the threshold value, for example at 30 dB. In this manner, the luminance can be adaptively adjusted in steps between particularly more than two succeeding sequences, which allows to identify a personalized threshold value for the luminance and associated sensitivity of the person, at which the person just barely correctly identifies the predefined number of optical stimuli positions. Particularly, a step width corresponding to a change of the sensitivity associated to the luminance can be decreased between succeeding sequences, for instance by a factor of two on the decibel scale. For example, the step width of the change of the sensitivity between the first and the second sequence is 8 dB, the step width between the second and the third sequence is 4 dB, the step width between the third and the fourth sequence is 2 dB and so forth. This measure allows to iteratively approximate to the personalized threshold value of the person, which decreases the amount of time necessary for the examination.

As such, by varying the luminance of the visual field with respect to the luminance of the optical stimulus, in other words by varying the contrast between the visual field and the optical stimulus, it may be investigated how the eye reactions associated with positional changes differ for different luminance or contrast conditions. To vary the luminance or contrast conditions, a luminance of the respective optical stimulus can be kept constant, for example at zero, while the luminance of the visual field is varied from sequence to sequence.

At least some sequences of measurement trials can comprise at least one succeeding measurement trial disclosed herein.

In particular, after each sequence, the contrast is iteratively adjusted by: decreasing the contrast, if the person has correctly identified a predetermined number of positions of the first and/or the second optical stimulus of the sequence, such that the detected eye reactions associated with the predetermined number of positions are according to criterion i) of claim 7 and increasing the contrast, if the person has not correctly identified a predetermined number of positions of the first and/or the second optical stimulus of the sequence, such that the detected eye reactions associated with the predetermined number of positions are according to criterion ii) of claim 7. Particularly, a personalized contrast threshold value of the person is determined from a contrast value against which the iterative adjustment of the contrast converges.

In an embodiment of the invention, the probability heatmap indicative of a defect in the visual field is determined based on the adjustment of the contrast. At positions in the visual field that are associated to scotoma, the optical stimuli are typically only correctly identified at higher contrasts compared to optical stimuli that are displayed at positions in the visual field that are devoid from scotoma. This information can be used to quantify the probability for a defect in terms of said probability value, based on the contrast value.

For example, the first plurality of positions and the second plurality of positions together comprise a total number of positions between 50 and 1000 positions of the second optical stimulus.

In an example, four sequences of measurement trials are subsequently executed, wherein for each sequence, the first plurality of positions of the first measurement trial and the second plurality of positions of the second measurement trial together comprise a total of 50 to 1000 positions and wherein the luminance of the portion of the visual field, particularly the entire visual field is adaptively adjusted starting from a first luminance corresponding to said predefined threshold value at which the person is likely to correctly identify the optical stimulus in the first sequence of measurement trials to a second, third and fourth luminance in the second, third and fourth sequence of measurement trials. Particularly, the four sequences are first applied to only one eye of the person and then only to the other eye of the person.

In an embodiment of the invention, a spatial separation in the visual field between positions of the first plurality of positions, particularly all positions of the first plurality of positions, is larger than a spatial separation in the visual field between positions of the second plurality of positions. As such, the visual field of the person may be sampled with a larger spatial step size between positions of the first plurality of positions than positions of the second plurality of positions, which improves the temporal efficiency of the adaptive sampling and iteratively adapts the sampling toward sections of the visual field with impairments.

In another embodiment of the invention, positions of the first plurality of positions are located in different quadrants of the visual field of the person.

In particular, the visual field of the person can be divided into a plurality of sections, for example sections with essentially the same size, wherein the positions of the first plurality of positions are located in different sections. As such, the first plurality of position can be distributed all over the visual field of the person, which allows to localize areas that are associated with impairments of the visual field, which may be further investigated within the second measurement trial.

According to another embodiment of the invention, a spatial density of the positions of the second plurality of positions in the visual field is larger than a spatial density of positions of the first plurality of positions in the visual field.

According to an embodiment of the invention, upon the second measurement trial, at least one succeeding measurement trial is performed, wherein for at least some, particularly for all of the succeeding measurement trials: i) the person is exposed to a subsequent optical stimulus in the visual field of the person, ii) wherein the subsequent optical stimulus is displayed subsequently to a precedent measurement trial such as the second measurement trial at a plurality of positions of a respective plurality of positions in the visual field of the person, iii) wherein the positions of the respective plurality of positions are located closer to positions of a plurality of positions of a preceding measurement trial that are associated with a smaller change in size of the pupil and/or lower saccadic efficiency than positions of the preceding plurality of positions that are associated with a larger change in size of the pupil and/or larger saccadic efficiency, wherein the preceding measurement trial precedes the succeeding measurement trial, iv) detecting the pupillary reaction of the person in response to a positional change of the subsequent optical stimulus between positions of the respective plurality of positions and thereby adaptively determining the visual field of the person based on the detected eye reactions. As such, the visual field can be iteratively sampled with increasing sampling rate by a plurality of measurement trials, wherein the plurality of positions of each succeeding measurement trial is based on the eye reactions of the preceding measurement trial. “Preceding” and “succeeding” measurement trials are preferably understood such that a succeeding measurement trial is the immediate next measurement trial of a preceding measurement trial, such that no other measurement trial is performed between the preceding and the succeeding measurement trial.

In particular, the positions of the respective plurality of positions are located closer to positions of a plurality of positions of at least one preceding measurement trial that are associated with a smaller change in size of the pupil and/or lower saccadic efficiency than positions of the at least one preceding plurality of positions that are associated with a larger change in size of the pupil and/or larger saccadic efficiency. For example, if a third measurement trial is performed, the corresponding third plurality of positions can be based on the changes in size of the pupil and/or the saccadic activity detected not only in the second measurement trial that immediately precedes the third measurement trial, but also on the changes in size of the pupil and/or the saccadic activity detected in the first measurement trial. As such, the detected changes in size of the pupil and/or the saccadic activity of multiple, particularly all preceding measurement trials may be used to determine the respective plurality of positions.

The subsequent, for example the third optical stimulus may correspond to the first optical stimulus and/or the second optical stimulus in terms of its shape, size, color, and/or contrast in the visual field. In particular, the subsequent optical stimulus and the first optical stimulus and/or the second optical stimulus are identical.

Alternatively, the subsequent optical stimulus and the first optical stimulus and/or the second optical stimulus differ in their size, color and/or contrast in the visual field.

In yet another embodiment of the invention, the eye reactions associated with the positional changes of the first optical stimulus, the second optical stimulus and/or the subsequent optical stimulus are mapped to a map representing the visual field of the person. The map can be a three-dimensional map with the x- and the y-axis of the visual field each corresponding to a spatial cartesian or angular coordinate, wherein the z-axis of the map perpendicular to the x- and the y-axis scales the eye reaction, particularly the change in diameter of the pupil and/or the saccadic efficiency. As such, impairments in the field of view of the person can be advantageously imaged or mapped in the visual field itself.

Alternatively or additionally, the map may be a heatmap with the coordinates representing the visual field coordinates and a color being indicative of the eye reaction.

In yet another embodiment, upon displaying of the first, the second and/or the subsequent optical stimulus at one position, a positional change of the first, the second and/or the subsequent optical stimulus from the one position to a subsequent position is made if one of the following criteria is met: i) a gaze position of the person in the visual field is located for a predefined dwell-time in a predefined area extending around the one position of the first, the second and/or the subsequent optical stimulus, or ii) the gaze position of the person in the visual field is not located in the predefined area extending around the one position of the first, the second and/or the subsequent optical stimulus within a predefined time limit upon displaying the first, the second and/or the subsequent optical stimulus at the one position. The above criteria i) and ii) can be used to classify when an optical stimulus is seen (i) or not seen (ii) by the person.

For example, for a visual field parametrized by angular coordinates, the predefined area extending around the one position of the first, second and/or the subsequent optical stimulus can be defined by means of a circle extending around the one position with a radius of 5°, 10° particularly 1°. Corresponding conditions can be defined for a visual field parametrized by cartesian coordinates.

The predefined dwell-time can be for example between 10ms and 2s, particularly between 50ms and 200ms.

The predefined time limit can be for example equal to or larger than the dwell-time, particularly between 500ms and 3s.

In case of criterium i), the stimulus may be referred to or classified as “seen”, wherein if criterium ii) is met, the stimulus may be is referred to or classified as “not seen”.

Particularly, the criteria i) and/or ii) for when an optical stimulus is classified as seen (i) or not seen (ii) additionally comprise a landing point accuracy. The landing point accuracy corresponds to the spatial separation between a stabilized gaze position of the person upon the positional change to the one position. For example, the landing point accuracy is within 5° in the visual field such that the optical stimulus counts as “seen”. In turn, if the landing point accuracy is beyond 5°, the optical stimulus may be counted as “not seen”.

In another embodiment of the invention, if the eye reaction determined for a positional change to a position is below a predefined threshold, the first, the second and/or the subsequent optical stimulus is arranged at an adjacent position of said position in a pre-defined distance to said position, and wherein an eye reaction is determined in response to a positional change to the adjacent position. For example, if one of the eye reactions detected for a positional change to a position of the first plurality of positions in the first measurement trial is below said predefined threshold, the first optical stimulus is first displayed at at least some the remaining positions of the first plurality of positions, and displayed at the adjacent position adjacent to said position later in or at the end of the first measurement trial. Particularly, the first, the second and/or the subsequent optical stimulus is arranged at an adjacent position of said position in a predefined distance to said position, if at the position the respective optical stimulus was classified to fall into criterion ii). These measures serve as a confirmation for possible impairments in the visual field. The adjacent position may be for example located within a distance of 5° with respect to said position. For example, the predefined threshold can be determined from an average change in size of the pupil and/or an average saccadic efficiency determined from all positional changes during the first measurement trial and/or the second measurement trial. For instance, 7 the predefined threshold may be defined by a factor multiplied with the respective average value, such as a threshold change in pupil size of 0.5 times the average change in pupil size.

According to another embodiment, if at least some of the eye reactions determined for positional changes of a preceding measurement trial are below said pre-defined threshold, a spatial density of positions of the succeeding measurement trial is decreased, i.e. the spatial sampling rate is reduced, compared to a spatial density of positions of the preceding measurement trial. In particular, the spatial density of positions of the succeeding measurement trial is decreased compared to the spatial density of the preceding measurement trial if all eye reactions determined for positional changes of the preceding measurement trial are below said predetermined threshold. This measure avoids that the adaptive sampling causes areas in the visual field that are associated with low eye reactions, and thus probably with an impairment of the visual field, to be repeatedly sampled. In turn, this embodiment allows for decreasing the spatial density of the sampling repeatedly if needed, such that other areas of the visual field can be sampled. A decrease of the spatial density in the succeeding measurement trial compared to the preceding measurement trial corresponds to increased distances between individual positions of the plurality of positions of the succeeding measurement trial, compared to the plurality of positions of the preceding measurement trial.

In yet another embodiment, if at least one of the eye reactions determined for positional changes of the first measurement trial is below said predefined threshold or classified to fall into criterion ii), at least some positions of the second measurement trial are comprised by a grid of positions with respect to the positions associated with eye reactions below said predefined threshold or classified to fall into criterion ii). The grid of positions can comprise positions that are located in different areas of the visual field with respect to the positions associated with eye reactions below said predefined threshold or classified to fall into criterion ii). The grid of positions can be a predefined grid, for example a grid forming and filling a geometrical shape at a predefined spatial sampling rate, extending around the positions that are associated to eye reactions below said predefined threshold or classified to fall into criterion ii). For example, the geometrical shape can be a rectangle, a square, a circle, and the like, particularly wherein the individual positions of/in the grid are arranged essentially equidistantly to each other. Alternatively, the grid of positions can be generated based on the detected eye reactions, for example wherein a neuronal network fed with the detected eye reactions, so as to generate the grid based on the detected eye reactions. Particularly, the neuronal network may additionally access other inputs such as a database comprising data indicative of known impairments of the visual field, such as scotomas, in order to generate the grid based on the detected eye reactions and other inputs. In particular, the grid of positions is generated by a machine learning algorithm, particularly a neural network, that uses the detected eye reactions as an input for the generation of the grid of positions. The input can further comprise data from a database encoding a plurality of visual field defects. The database may comprise data encoding spatial information of previously determined visual field defects, for example including positions and spatial extent of previously determined scotoma. This information can be used as a further input for the machine learning algorithm to render the generation of the grid more efficient.

Particularly, at least a section of a boundary of a defect in the visual field is determined based on the detected eye reactions associated with the positions of the grid of positions, wherein the grid of positions is generated by the machine learning algorithm, particularly the neural network, that uses the detected eye reactions and particularly said data from said database as an input for the generation of the grid of positions. As such, the section of the boundary or the total boundary of the defect in the visual field can be determined based on the machine learning algorithm, which substantially speeds up the determination of the position and spatial extent of visual field impairments.

In another embodiment of the invention, a probability heatmap indicative of a defect is determined based on the detected eye reactions. In particular, the probability heatmap assigns a probability value to each position of the first plurality of positions and/or to each position of the second plurality of positions, wherein the probability value is indicative of a probability for a defect at the respective position. Preferably, the probability value assumes at least three different values, such that it comprises more information than a binary classification for the presence or absence of a defect in the visual field. For example, the probability value can be a value between 0 and 100, wherein a higher probability value indicates a higher probability for a defect. The probability value can be determined based on the detected eye reaction associated with the respective position. For example, the probability value can be determined quantitatively by the strength of the detected eye reaction, for instance based on the detected change of the pupil size. The probability value can additionally or alternatively be determined by or assisted by the machine learning algorithm. The probability heatmap is a more realistic representation of a defect in the visual field, which typically represents only a partial loss of sensitivity (blindness) in areas of the visual field, compared to a defect defined by a hard boundary between a fully functional and completely dysfunctional area in the visual field.

For example, the positions of the second measurement trial can comprise positions that are located in regular angular intervals around the positions associated with eye reactions below said predefined threshold or classified to fall into criterion ii), particularly in angular intervals of 30°, 60° or 90°. As such, the vicinity of positions that are associated with impairments of the visual field can be sampled along predefined directions, which allows to localize edges of the impairment of the visual field, i.e. transition areas in the visual field where the eye reactions change substantially. This embodiment allows to obtain information about the spatial extent and the spatial limitations of impairments of the visual field.

According to an embodiment of the invention, only one eye of the person at a time is exposed to the first, the second and/or the subsequent optical stimulus, such that only the eye reaction of the one eye is determined. For example, only one eye of the person is exposed to the optical stimuli, while the other eye is closed by means of a shutter, such that the other eye is not exposed to the optical stimuli. The first measurement trial and/or the second measurement trial may subsequently be performed for the respective other eye, so as to adaptively sample the visual field of both eyes separately.

In yet another embodiment, the first, the second and/or the subsequent optical stimulus is applied by means of a display, particularly a display integrated in goggles to be worn by the person, particularly a display of a head-mounted display.

A second aspect of the invention relates to a computer program for adaptive sampling of a visual field of a person. The computer program comprises instructions which, when the program is executed by a computer, cause the computer to:

- cause an optical device to:

• generate an optical stimulus at a plurality of positions in the visual field of the person and

• detect for at least some of the positions an eye reaction of the person in response to a positional change of the optical stimulus between two subsequently displayed positions, wherein the eye reaction is selected from one or more of a group consisting of: a change in size of a pupil and/or a saccade,

• in a first measurement trial, expose at least one eye of the person to a first optical stimulus in the visual field of the person, wherein the first optical stimulus is displayed subsequently at a plurality of positions of a first plurality of positions and for at least some positions of the first plurality of positions, particularly for all positions of the first plurality of positions, detect the eye reaction of the person in response to a positional change of the first optical stimulus between two subsequently displayed positions of the first plurality of positions, and

• in a second measurement trial, expose the at least one eye of the person to a second optical stimulus in the visual field of the person, wherein the second optical stimulus is displayed subsequently at a plurality of positions of a second plurality of positions, wherein the positions of the second plurality are located closer to positions of the first measurement trial that are associated with a smaller change in size of the pupil and/or lower saccadic efficiency, particularly wherein a lower saccadic efficiency is associated to longer saccadic latencies and/or lower gaze position accuracies of the person in response to positional changes of the first optical stimulus than positions of the first measurement trial that are associated with a larger change in size of the pupil and/or larger saccadic efficiency, particularly wherein a larger saccadic efficiency is associated to shorter saccadic latencies and/or higher gaze position accuracies of the person in response to positional changes of the first optical stimulus and to detect the eye reaction of the person in response to a positional change of the second optical stimulus between positions of the second plurality of positions,

- thereby adaptively sample the visual field of the person based on the detected eye reactions.

In other words, the computer is configured to execute the computer-implemented steps of the method according to the first aspect of the invention. The embodiments of the first aspect of the invention can therefore also be applied to the second aspect of the invention.

For this purpose, the computer may be connected to or comprised by an optical system for adaptive sampling of a visual field of a person, said system being configured to display the stimuli to the person, wherein the system is configured to by controlled by the computer.

A third aspect of the invention relates to a system for adaptive sampling of a visual field of a person. The system comprises: an optical device configured to:

• generate an optical stimulus at a plurality of positions in the visual field of the person,

• detect an eye reaction of the person in response to a positional change of the optical stimulus between positions, wherein the eye reaction is selected from one or more of a group consisting of: a change in size of a pupil and/or a saccade and

- the computer according to the second aspect of the invention.

Since the system according to the third aspect of the invention comprises the computer according to the second aspect of the invention, which is configured to execute the computer- implemented steps of the method according to the first aspect of the invention, the embodiments of the first aspect of the invention can also be applied to the third aspect of the invention.

In particular, features, definitions and/or embodiments disclosed in the context of the first or second aspect may be used to limit or define the invention according to the third aspect in the same or accordingly analogue fashion. Particularly, the optical device of the system according to the third aspect of the invention is integrated in goggles, particularly in a head-mounted display to be worn by the person. The computer may or may not be integrated in the goggles.

The optical device can receive data indicative of commands of the computer that cause the optical device to generate the stimuli at positions and send data indicative of the detected eye reaction of the person in response to positional changes of the optical stimulus between positions to the computer, such that the computer can adaptively sample the visual field of the person.

To this end, if the computer is integrated in the goggles, the optical device and the computer can communicate for example via cable-based communication means. If the computer is not integrated in the goggles, the optical device and the computer can communicate particularly via wireless communication means.

The system according to third aspect of the invention particularly allows to determine the pupillary light reflex independently of educated medical personnel and independent of medical infrastructure. For example, the computer program can be executed on conventional goggles, particularly conventional augmented and/or virtual reality goggles such as head-mounted displays, which are becoming increasingly popular for home use.

Exemplary embodiments are described below in conjunction with the Figures. The Figures are appended to the claims and are accompanied by text explaining individual features of the shown embodiments and aspects of the present invention. Each individual feature shown in the Figures and/or mentioned in the text of the Figures may be incorporated (also in an isolated fashion) into a claim relating to the first aspect, the second aspect and/or the third aspect according to the present invention.

Fig. 1 shows a first measurement trial according to an embodiment of the invention;

Fig. 2 shows a second measurement trial according to an embodiment of the invention;

Fig. 3 shows a map of a visual field of the person, indicating areas that are associated with lower saccadic efficiency and/or lower gaze position accuracies; and

Fig. 4 shows an embodiment of a system for adaptive sampling of a visual field of a person. Fig. 1 shows a first measurement trial according to an embodiment of the invention. According to the present embodiment, to adaptively sample a visual field 1 of a person, at least one eye of the person is in the first measurement trial exposed to a first optical stimulus 11. For example, only one eye of the person is exposed to the first optical stimulus 11 , while the other eye is closed by means of a shutter, such that the other eye is not exposed to the first optical stimulus 11. The first measurement trial and/or the second measurement trial (cf. Fig. 2) may subsequently be performed for the respective other eye, in order to adaptively sample the visual field 1 of both eyes separately.

For the exposure of the eye to the first optical stimulus 11 , the first optical stimulus 11 is displayed on a display 4. By means of an example, the display 4 shown in Fig. 1 has a rectangular shape, such as a monitor. However, the display 4 can for example also be part of a head-mounted display, particularly wherein, other than shown in Fig. 1 , a corresponding virtual display field of the display 4 can be substantially larger than the visual field 1. Fig. 1 shows a scotoma 3 in the visual field 1 of the person, which shall be detected by adaptive sampling of the visual field 1 according to the present embodiment of the invention.

In the first measurement trial, the optical stimulus 11 is displayed subsequently at a first plurality of positions of a first plurality of positions in the visual field 1. To this end, the first optical stimulus 11 is displayed at different positions on the display 4, wherein the person is looking at the display 4 such that the first stimulus 11 is located in the visual field 1 of the person. The gaze position 20 forms the origin of the visual field 1 . As the gaze position 20 of the person changes in a saccade 30 in response to a positional change of the first optical stimulus 11 on the display 4 and thus in the visual field 1 , the visual field 1 shifts with respect to the display 4, as can also be understood from the four positional changes indicated in Fig. 1.

Fig. 1 shows from top to bottom four saccades 30,31 a, 32a, 33a, 34a determined in response to positional changes of the first optical stimulus 11 between four display positions 41 a, 42a, 43a, 44a on the display 4 during the first measurement trial. Besides said saccades, a change in size of the pupil can additionally be detected in response to each positional change of the first optical stimulus 11 between two subsequently displayed positions of the first plurality of positions, which can deliver additional information on impairments in the visual field 1.

A first saccade 31a is triggered by the display of the first optical stimulus 11 at a first display position 41a on the display 4, wherein the first display position 41a corresponds to a position in a second quadrant Q2 of the visual field 1. In response to the display of the first optical stimulus 11 at the first display position 41a, the gaze position 20 of the person moves in the first saccade 31a from a first gaze position 21a to a second gaze position 22a in the second quadrant Q2 of the visual field 1 . Subsequently, a second saccade 32a is triggered by a positional change of the first optical stimulus 11 in the visual field 1 from the first display position 41a to a second display position 42a on the display 4. The second saccade 32a corresponds to a movement of the gaze position 20 from the second gaze position 22a to a third gaze position 23a in a first quadrant Q1 of the visual field 1. A third saccade 33a is triggered by a positional change of the first optical stimulus 11 from the second display position 42a to a third display position 43a on the display 4. The third saccade 33a corresponds to a movement of the gaze position 20 from the third gaze position 23a to a fourth gaze position 24a in a fourth quadrant Q4 of the visual field 1 . A fourth saccade 34a is triggered by a positional change of the first optical stimulus 11 from the third display position 43a to a fourth display position 44a. The fourth saccade 34a corresponds to a movement of the gaze position 20 from the fourth gaze position 24a to a fifth gaze position 25a in a third quadrant Q3 of the visual field 1 . As such, the positions of the first plurality of positions according to the present embodiment are located in different quadrants Q1 ,Q2,Q3,Q4 of the visual field 1 of the person, wherein the quadrants Q1 ,Q2,Q3,Q4 divide the visual field 1 in four portions with respect to the current gaze position 20.

The positions of the first plurality of positions thus correspond to relative positions in the visual field 1 of the person with respect to the origin of the visual field 1 , which is defined by the gaze position 20. These relative positions in the visual field 1 are related to absolute display positions, such as the first, second third and fourth display position 41 a, 42a, 43a, 44a, through the spatial arrangement of the display 4 with respect to the eye of the person. As such, the positions of the first optical stimulus 11 can likewise be parametrized in a coordinate system of the display 4, on which the first optical stimulus 11 is displayed. The same applies for the second optical stimulus 12 and the subsequent, for example the third optical stimulus disclosed herein.

Preferably, the area of the display 4 is large enough and/or the distance between the eye of the person and the display 4 is short enough, such that a majority of the visual field 1 is in overlap with the display 4, as is the case in Fig. 1 , which allows for sampling of large areas of the visual field 1. Particularly, to this end, a head-mounted display can be used, wherein the display 4 covers the majority or the entire visual field 1 , particularly wherein a virtual display field of the display 4 is larger than the entire visual field 1. Displaying the first optical stimulus 11 in different quadrants Q1 ,Q2,Q3,Q4 of the visual field 1 realizes a coarse sampling of areas with relatively large separations in the visual field 1 , which allows to localize impairments such as scotoma 3 in distant portions of the visual field 1 .

Fig. 2 shows a second measurement trial according to an embodiment of the invention. In particular, the second measurement trial according to the present embodiment may be executed after executing the first measurement trial according to the embodiment of Fig. 1. In other words, Fig. 1 and Fig. 2 can be understood as one embodiment.

To adaptively sample the visual field 1 of the person, preferably the same eye that has been exposed to the first optical stimulus 11 in the first measurement trial is in the second measurement trial exposed to a second optical stimulus 12 in the visual field 1 of the person. The shape, size and contrast can be identical for the first optical stimulus 11 and the second optical stimulus 12.

In the present embodiment, it is assumed that in the first measurement trial preceding the second measurement trial, the positional change of the first optical stimulus 11 from the first display position 41a to the second display position 42a associated with the first saccade 31a from the first gaze position 21a to the second gaze position 22a into the second quadrant Q2 of the visual field 1 is associated with a smaller detected change in size of the pupil of the person and/or lower detected saccadic efficiencies, than the positional changes associated to the second, third and fourth saccade 32a, 33a, 34a of the first measurement trial shown in Fig. 1. This is due to the fact that as the first optical stimulus 11 was displayed at the first display position 41a, the first optical stimulus 11 was located in the area of a scotoma 3 located in the second quadrant Q2 of the visual field 1 , while the other stimulus positions were located in areas of the visual field 1 without a scotoma 3, cf. Fig. 1. Lower saccadic efficiency is in particular associated to longer saccadic latencies and/or lower gaze position 20 accuracies of the person in response to positional changes of the first optical stimulus 11 than positional changes of the first measurement trial that are associated with a larger change in size of the pupil and/or larger saccadic efficiency, particularly wherein a larger saccadic efficiency is associated to shorter saccadic latencies and/or higher gaze position 20 accuracies of the person in response to positional changes of the first optical stimulus 11.

A smaller detected change in size of the pupil of the person and/or lower detected saccadic efficiency in response to the positional change of the first optical stimulus 11 associated with the first saccade 31a from the first gaze position 21a to the second gaze position 22a in the second quadrant Q2 than the positional changes related to the second, third and fourth saccade 32a, 33a, 34a into the other quadrants Q1 ,Q3,Q4 of the visual field 1 points to impairments in the visual field 1 of the person in the second quadrant Q2, but not in the other quadrants Q1 ,Q3,Q4. In the second measurement trial, this information is used in the sense that in the second measurement trial, the second optical stimulus 12 is subsequently displayed at a second plurality of positions in the visual field 1 , wherein positions of the second plurality of positions are located closer to positions in the visual field 1 of the first measurement trial that are associated with a smaller detected change in size of the pupil and/or lower detected saccadic efficiency. This measure allows for an adaptive sampling of the visual field 1. Fig. 2 shows from top to bottom five saccades 30,31 b, 32b, 33b, 34b, 35b determined in response to positional changes of the second optical stimulus 12 between six display positions 41 b, 42b, 43b, 44b, 45b, 46b on the display 4 during the second measurement trial. As in the first measurement trial, the eye reaction of the person is detected in response to each positional change of the second optical stimulus 12 in the second measurement trial.

Upon display of a first display position 41 b, the gaze position 20 of the person moves to a first gaze position 21 b that serves as a reference starting point, such that the display of a subsequent second display position 42b can cause a saccade 30 toward the scotoma 3 detected for the first display position 41a of the first measurement trial. The display of the second optical stimulus 12 at the second display position 41b may or may not trigger a saccade 31 b from the first gaze position 21 b to a second gaze position 22b into the second quadrant Q2 of the visual field 1 , depending on whether the person sees the second optical stimulus 12 in the vicinity of the scotoma 3 or not. If the person sees the second optical stimulus 12 at the second display position 42b, the gaze position 20 moves in the first saccade 31b from the first gaze position 21 b to the second gaze position 22b. The second optical stimulus 12 is subsequently shown at a third display position 43b, which is located close to the original, first display position 41b. As such, a thereby triggered second saccade 32b corresponds to a movement of the gaze position 20 from the second gaze position 22b to a third gaze position 23b diagonally into the fourth quadrant Q4 of the visual field 1. This is to reset the gaze position 20 such that a following third saccade 33b can again be directed in the area close to the scotoma 3 detected in the second quadrant Q2 of the visual field 1. To this end, the second optical stimulus 12 is subsequently displayed at a fourth display position 44b that corresponds to a position in the area of the scotoma 3 in the coordinate system of the visual field 1. If the person sees the second optical stimulus 12 at the fourth display position 44b, this triggers a third saccade 33b from the third gaze position 23b to a fourth gaze position 24b. Subsequently, the gaze position 20 is again reset by displaying the second optical stimulus 12 at a fifth display position 45b, which triggers a fourth saccade 34b from the fourth gaze position 24b to a fifth gaze position 25b into the fourth quadrant Q4. Displaying the second optical stimulus 12 at a sixth display position 46b as indicated in Fig. 2 then again allows to sample a position in the visual field 1 in the vicinity of the scotoma 3. As such, the display positions 42b, 44b, 46b and the associated saccades 31b, 33b, 35b represent a fine sampling of the visual field 1 in the area of the scotoma 3 detected during the coarse sampling of the visual field 1 in the first measurement trial. The display positions 41 b, 43b, 45b serve as reset positions for resetting the gaze position 20 such that positions in the visual field 1 near the scotoma 3 can be repeatedly sampled. This process of sampling positions in the visual field 1 near the scotoma 3 detected in the first measurement trial, as for the display positions 42b, 44b, 46b, alternated with a reset *? of the gaze position 20, as for the display positions 41 b, 43b, 45b, may be repeated multiple times to obtain spatial information about the scotoma 3 in the visual field 1.

As such, the second measurement trial accounts for the detected eye reactions of the first measurement trial to adaptively adjust the spatial sampling of the visual field 1. This measure contributes to a substantial reduction of time needed to sample the visual field 1. In particular, in this way, the sampling is not performed repeatedly in regions that are known to be associated with eye reactions that point to a sufficient functionality of the eye, but adaptively adjusts to areas in the visual field 1 that are associated with impairments such as a scotoma 3.

As can be understood from comparing Fig. 1 and Fig. 2, a spatial separation between positions of the first plurality of positions in the visual field 1 is larger than a spatial separation between positions of the second plurality of positions in the visual field 1 , which reflects the adaptive character of the sampling of the visual field 1 in the second measurement trial than the first measurement trial. In other words, a spatial density of the positions of the second plurality of positions in the visual field 1 is larger than a spatial density of positions of the first plurality of positions in the visual field 1 . In this example embodiment, this holds particularly for the display positions 42b, 44b, 46b that are used for the fine sampling of the visual field 1.

Positional changes of the first optical stimulus 11 and/or the second optical stimulus 12 from one position to a subsequent position can be made if upon displaying the first and/or the second optical stimulus at the one position, the gaze position 20 of the person in the visual field 1 is located for a pre-defined dwell-time in a pre-defined area extending around the one position. If this is the case, the person has correctly identified the position of the optical stimulus, such that the optical stimulus can be classified as to fall in a criterion i), which may be equivalently referred to as “seen” in the context of the current specification, and the optical stimulus is displayed at the subsequent position. Alternatively, positional changes of the first optical stimulus 11 and/or the second optical stimulus 12 from one position to a subsequent position can be made if upon displaying the first optical stimulus 11 and/or the second optical stimulus 12 at the one position, the gaze position 20 of the person in the visual field 1 is not located in a predefined area extending around the one position of the first optical stimulus 11 and/or the second optical stimulus 12 within a predefined time limit upon displaying the first optical stimulus 11 and/or the second optical stimulus 12 at the one position. If this is the case, the person has not correctly identified the position of the optical stimulus, such that the optical stimulus may be classified to fall into a criterion ii) which may be referred to as “not seen” equivalently in the context of the current specification. If the optical stimulus is classified as “not seen”, i.e. to fall into criterion ii), the associated positional change is assigned a smaller change in size of the pupil and/or lower saccadic efficiency, than positions that are classified as “seen”, i.e. to fall into criterion i). Consequently, for example, if one position of the first plurality of positions in the first measurement trial is classified as “not seen”, while the other positions of the first plurality of positions are classified as “seen”, the positions of the second plurality of positions in the following second measurement trial can be closer to the position of the first measurement trial which was classified as “not seen”.

Optionally, upon the second measurement trial, a subsequent measurement trial can be performed. For the subsequent measurement trial, the person is exposed to a subsequent optical stimulus in the visual field 1 of the person. The subsequent optical stimulus may correspond to the size, shape and/or contrast of the first optical stimulus 11 and the second optical stimulus 12. The subsequent optical stimulus is displayed subsequently at a subsequent plurality of positions in the visual field 1 of the person. The positions of the subsequent plurality of positions are located closer to positions of the second plurality of positions that are associated with a smaller change in size of the pupil and/or a lower saccadic efficiency, than positional changes of the second measurement trial that are associated with a larger change in size of the pupil and/or larger saccadic efficiency. The pupillary reaction of the person is detected for positional changes of the subsequent optical stimulus between positions of the subsequent plurality of positions. As such, the subsequent measurement trial represents a further adaption of the spatial sampling of the visual field 1 , based on the eye reactions detected in the second measurement trial. In the same fashion, succeeding measurement trials can be performed whose respective plurality of positions are based on the eye reactions detected in preceding measurement trials.

Particularly, if the eye reaction determined for a positional change to a position is below a predefined threshold, the respective optical stimulus is displayed at an adjacent position of said position in a predefined distance to said position and an eye reaction is determined in response to a positional change to the adjacent position. This measure serves as a confirmation for possible impairments in the visual field 1. For example, if one of the eye reactions detected for a positional change to a position of the first plurality of positions in the first measurement trial is below said predefined threshold, the first optical stimulus 11 is first displayed at at least some the remaining positions of the first plurality of positions, and displayed at the adjacent position adjacent to said position later or at the end of the first measurement trial.

Moreover, optionally, if at least some of the eye reactions determined for positional changes of a preceding measurement trial are below said predefined threshold, a spatial density of positions of the succeeding measurement trial is decreased compared to a spatial density of positions of the preceding measurement trial. In particular, the spatial density of positions of the succeeding measurement trial is decreased compared to the spatial density of the preceding measurement trial if all eye reactions determined for positional changes of the preceding measurement trial are below said predetermined threshold. This measure avoids that the adaptive sampling causes areas in the visual field 1 that are associated with low eye reactions, and thus probably with an impairment of the visual field 1 , are repeatedly sampled and that in turn, the spatial density of the sampling is decreased, such that other areas of the visual field 1 can be sampled.

In Fig. 3, the eye reactions associated with the positional changes of the first optical stimulus 11 within the first measurement trial and the second optical stimulus 12 within the second measurement trial based on the embodiment of Fig. 1 and Fig. 2 are schematically mapped in the visual field 1. The black areas indicate areas of the visual field 1 of the person that are associated with smaller detected changes in size of the pupil of the person and/or lower detected saccadic efficiencies compared to the white areas. Since in the embodiment of Fig.

I and Fig. 2 the eye reactions in a specific area of the second quadrant Q2 corresponding to said scotoma 3 are less pronounced than the eye reactions in the other quadrants Q1 ,Q3,Q4, the map indicates a black spot in the second quadrant Q2 that indicates the positional changes of the first optical stimulus 11 and/or the second optical stimulus 12 associated with less pronounced eye reactions. The map shown in Fig. 3 therefore provides an advantageous spatial representation of the visual field 1 of the person that highlights its impairments, here by means of a scotoma 3. The spatial resolution of the black spot corresponds to the spatial sampling of the plurality of positions of the first and/or the second measurement trial.

Fig. 4 shows a system 100 for adaptive sampling of a visual field 1 of a person, according to an embodiment of the third aspect of the invention. The system 100 comprises a computer 50 as well as an optical device 60 that are, according to the present embodiment, integrated in or on the goggles 70, particularly a head-mounted display, to be worn by the person.

Based on instructions of a computer program according to the second aspect of the invention, which is executed by the computer 50, the optical device 60 is configured to generate an optical stimulus at a plurality of positions in the visual field 1 of the person. The optical stimulus is displayed such to the person that it is arranged in the visual field 1 of the person defined by the eyes 2a, 2b of the person. By means of an example, Fig. 4 depicts the first optical stimulus

I I displayed to the person in the visual field 1 of the left eye 2a of the person. The right eye 2b of the person may or may not be exposed to the first optical stimulus 11. In particular, first one of the eyes 2a, 2b of the person may be exposed to the optical stimulus, whereafter the other of the two eyes 2b, 2a of the person is exposed to the optical stimulus, so as to adaptively sample the visual field 1 for both eyes 2a, 2b of the person separately. The optical device 60 is further configured to detect, particularly to track eye reactions of the person in response to positional changes of the optical stimulus between positions, wherein the eye reaction is selected from one or more of a group consisting of: a change in size of a pupil and/or a saccade 30.

The eye reactions detected by the optical device 60, particularly the detected changes in size of the pupil and/or the saccades 30, are processed by the computer 50 for the adaptive sampling of the visual field 1 , for example according to the embodiment of Fig. 1 and Fig. 2.

The computer program executed by the computer 50 may further be configured to generate data indicative of a map of the visual field 1 mapping the eye reactions, for example according to the embodiment of Fig. 3.

The system 100 according to the present embodiment particularly allows adaptively sample the visual field 1 of a person independently of educated medical personnel and independent of medical infrastructure. For example, the computer program can be executed on conventional goggles, particularly conventional augmented and/or virtual reality goggles, more particularly a head-mounted display, which are becoming increasingly popular for home use.

List of reference signs

Visual field

Left eye of the person 2a

Right eye of the person 2b

Scotoma 3

Display 4

First optical stimulus 11

Second optical stimulus 12

Gaze position 20

First gaze position of first measurement trial 21a

First gaze position of second measurement trial 21b

Second gaze position of first measurement trial 22a

Second gaze position of second measurement trial 22b

Third gaze position of first measurement trial 23a

Third gaze position of second measurement trial 23b

Fourth gaze position of first measurement trial 24a

Fourth gaze position of second measurement trial 24b

Fifth gaze position 25

Saccade 30

First saccade of first measurement trial 31a

First saccade of second measurement trial 31b

Second saccade of first measurement trial 32a

Second saccade of second measurement trial 32b

Third saccade of first measurement trial 33a

Third saccade of second measurement trial 33b

Fourth saccade of first measurement trial 34a

Fourth saccade of second measurement trial 34b

Fifth saccade of second measurement trial 35b First display position of first measurement trial 41a

First display position of second measurement trial 41 b

Second display position of first measurement trial 42a

Second display position of second measurement trial 42b Third display position of first measurement trial 43a

Third display position of second measurement trial 43b

Fourth display position of first measurement trial 44a

Fourth display position of second measurement trial 44b

Fifth display position of second measurement trial 45b Sixth display position of second measurement trial 46b

Computer 50

Optical device 60

Goggles 70

System 100 First quadrant of the visual field Q1

Second quadrant of the visual field Q2

Third quadrant of the visual field Q3

Fourth quadrant of the visual field Q4

Claims

Patent claims:

1. A method, particularly a computer-implemented method, for adaptive sampling of a visual field (1) of a person, wherein the method comprises the following steps:

- in a first measurement trial, exposing at least one eye of the person to a first optical stimulus (11) in the visual field (1) of the person, wherein the first optical stimulus (11) is displayed subsequently at a plurality of positions of a first plurality of positions in the visual field (1), and detecting for at least some positions of the first plurality of positions, an eye reaction of the person in response to a positional change of the first optical stimulus (11) between two subsequently displayed positions of the first plurality of positions, wherein the eye reaction is selected from one or more of a group consisting of: a change in size of a pupil and/or a saccade (30),

- in a second measurement trial, exposing the at least one eye of the person to a second optical stimulus (12) in the visual field (1) of the person, wherein the second optical stimulus (12) is displayed subsequently at a second plurality of positions in the visual field (1), wherein positions of the second plurality are located closer to positions of the first measurement trial that are associated with a smaller change in size of the pupil and/or a lower saccadic efficiency than positions of the first measurement trial that are associated with a larger change in size of the pupil and/or a larger saccadic efficiency, and detecting the eye reaction of the person in response to a positional change of the second optical stimulus (12) between positions of the second plurality of positions, and thereby adaptively sampling the visual field (1) of the person based on the detected eye reactions.

2. The method according to claim 1 , wherein a spatial separation in the visual field (1) between positions of the first plurality of positions is larger than a spatial separation in the visual field (1) between positions of the second plurality of positions.

3. The method according to claim 1 or 2, wherein positions of the first plurality of positions are located in different quadrants (Q1 ,Q2,Q3,Q4) of the visual field (1) of the person.

4. The method according to one of the preceding claims, wherein a spatial density of the positions of the second plurality of positions in the visual field (1) is larger than a spatial density of positions of the first plurality of positions in the visual field (1).

5. The method according to one of the preceding claims, wherein upon the second measurement trial, at least one succeeding measurement trial is performed, wherein for at least some, particularly for all of the succeeding measurement trials: i) the person is exposed to a subsequent optical stimulus in the visual field (1) of the person, ii) wherein the subsequent optical stimulus is displayed subsequently at a plurality of positions of a respective plurality of positions in the visual field (1) of the person, iii) wherein the positions of the respective plurality of positions are located closer to positions of a plurality of positions of a preceding measurement trial that are associated with a smaller change in size of the pupil and/or lower saccadic efficiency than positions of the preceding plurality of positions that are associated with a larger change in size of the pupil and/or larger saccadic efficiency, wherein the preceding measurement trial precedes the succeeding measurement trial, iv) detecting the pupillary reaction of the person in response to a positional change of the subsequent optical stimulus between positions of the respective plurality of positions and thereby adaptively determining the visual field (1) of the person based on the detected eye reactions.

6. The method according to one of the preceding claims when referring to the first optical stimulus (11) and the second optical stimulus (12) and according to claim 5 when referring to the subsequent optical stimulus, wherein the eye reactions associated with the positional changes of the first optical stimulus (11), the second optical stimulus (12) and/or the subsequent optical stimulus are mapped on a map depicting the visual field (1) of the person.

7. The method according to one of the preceding claims when referring to the first optical stimulus (11) and the second optical stimulus (12) and according to claim 5 or claim 6 when referring to the subsequent optical stimulus, wherein upon displaying of the first, the second and/or the subsequent optical stimulus (11 ,12) at one position, a positional change of the first, the second and/or the subsequent optical stimulus (11,12) from the one position to a subsequent position is made if one of the following criteria is met: i) a gaze position (20) of the person in the visual field (1) is located for a predefined dwell-time in a pre-defined area extending around the one position of the first, the second and/or the subsequent optical stimulus (11 ,12), or ii) the gaze position (20) of the person in the visual field (1) is not located in a pre-defined area extending around the one position of the first, the second and/or the subsequent optical stimulus (11 ,12) within a predefined time limit upon displaying the first, the second and/or the subsequent optical stimulus (11 ,12) at the one position.

8. The method according to one of the preceding claims, wherein, if the eye reaction determined for a positional change to a position is below a predefined threshold, particularly if the eye reaction is according to criterion ii) of claim 7, the first, the second and/or the subsequent optical stimulus (11 ,12) is displayed at an adjacent position of said position in a predefined distance to said position, and wherein an eye reaction is determined in response to a positional change to the adjacent position.

9. The method according to claim 8, wherein, if at least some of the eye reactions determined for positional changes of a preceding measurement trial are below said predefined threshold, a spatial density of positions of the succeeding measurement trial is decreased compared to a spatial density of positions of the preceding measurement trial.

10. The method according to claim 9, wherein the spatial density of positions of the succeeding measurement trial is decreased compared to the spatial density of the preceding measurement trial if all eye reactions determined for positional changes of the preceding measurement trial are below said predetermined threshold.

11. The method according to claim 7, 8 and any one of the preceding claims, wherein if at least one of the eye reactions determined for positional changes of the first measurement trial is below said predefined threshold or classified to fall into criterion ii), at least some positions of the second measurement trial are comprised by a grid of positions with respect to the positions associated with eye reactions below said predefined threshold or classified to fall into criterion ii).

12. The method according to claim 11 , wherein the grid of positions is generated by a machine learning algorithm, particularly a neural network, that uses the detected eye reactions as an input for the generation of the grid of positions.

13. The method according to claim 12, wherein the input further comprises data from a database encoding a plurality of visual field defects.

14. The method according to claim 12 or 13, wherein at least a section of a boundary of a defect in the visual field (1) is determined based on the detected eye reactions associated with the positions of the grid of positions.

15. The method according to one of the preceding claims, wherein a probability heatmap indicative of a defect in the visual field is determined based on the detected eye reactions.

16. The method according to claim 15, wherein the probability heatmap assigns a probability value to each position of the first plurality of positions and/or to each position of the second plurality of positions, wherein the probability value is indicative of a probability for a defect at the respective position.

17. The method according to claim 16, wherein the probability value can assume at least three different values.

18. The method according to one of the preceding claims, wherein a plurality of sequences of measurement trials are performed, each sequence comprising at least the first and the second measurement trial, wherein in a second sequence comprised by the plurality of sequences, a contrast between at least a portion of the visual field, particularly the entire visual field, and the respective optical stimulus is adjusted based on detected eye reactions of the person during a first sequence comprised by the plurality of sequences preceding the second sequence.

19. The method according to claim 18 when referring to claim 7, wherein after each sequence, the contrast is iteratively adjusted by: decreasing the contrast, if the person has correctly identified a predetermined number of positions of the first and/or the second optical stimulus (11 ,12) of the sequence, such that the detected eye reactions associated with the predetermined number of positions are according to criterion i) of claim 7 and increasing the contrast, if the person has not correctly identified a predetermined number of positions of the first and/or the second optical stimulus (11 ,12) of the sequence, such that the detected eye reactions associated with the predetermined number of positions are according to criterion ii) of claim 7.

20. The method according to claim 19, wherein a personalized contrast threshold value of the person is determined from a contrast value against which the iterative adjustment of the contrast converges.

21. The method according to one of the claims 18 to 20 and one of the claims 15 to 17, wherein the probability heatmap is determined based on the adjustment of the contrast.

22. The method according to one of the preceding claims, wherein the first, the second and/or the subsequent optical stimulus is applied by means of a display, particularly a display integrated in goggles to be worn by the person.

23. The method according to one of the preceding claims, wherein at most 40%, particularly at most 30%, more particularly at most 20% of the positions of the first plurality of positions are identical.

24. The method according to one of the preceding claims, wherein the first plurality of positions is devoid of a reset position for resetting the gaze position upon saccades triggered by positional changes of the first optical stimulus (11).

25. The method according to one of the preceding claims, wherein a majority of the positions, particularly 60%, more particularly 70% of the first plurality of positions are different from each other.

26. The method according to claim 25, wherein all positions of the first plurality of positions in the first measurement trial are different from each other.

27. The method according to one of the claims 23 to 26, wherein some of the positions of the second plurality of positions are reset positions for the resetting the gaze position upon saccades triggered by positional changes of the second optical stimulus (12).

28. A computer program for adaptive sampling of a visual field (1) of a person, wherein the computer program comprises instructions which, when the program is executed by a computer (50), cause the computer (50) to:

- cause an optical device (60) to:

• generate an optical stimulus at a plurality of positions in the visual field (1) of the person and

• detect for at least some of the positions an eye reaction of the person in response to a positional change of the optical stimulus between two subsequently displayed positions, wherein the eye reaction is selected from one or more of a group consisting of: a change in size of a pupil and/or a saccade (30),

• in a first measurement trial, expose at least one eye of the person to a first optical stimulus (11) in the visual field (1) of the person, wherein the first optical stimulus (11) is displayed subsequently at a plurality of positions of a first plurality of positions in the visual field (1) and for at least some positions of the first plurality of positions detect the eye reaction of the person in response to a positional change of the first optical stimulus (11) between two subsequently displayed positions of the first plurality of positions, and

• in a second measurement trial, expose the at least one eye of the person to a second optical stimulus (12) in the visual field (1) of the person, wherein the second optical stimulus (12) is displayed subsequently at a plurality of positions of a second plurality of positions in the visual field (1), wherein the positions of the second plurality are located closer to positions of the first measurement trial that are associated with a smaller change in size of the pupil and/or lower saccadic efficiency than positions of the first measurement trial that are associated with a larger change in size of the pupil and/or larger saccadic efficiency, and to detect the eye reaction of the person in response to a positional change of the second optical stimulus (12) between positions of the second plurality of positions,

- thereby adaptively sample the visual field (1) of the person based on the detected eye reactions.

29. A system (100) for adaptive sampling of a visual field (1) of a person, wherein the system (100) comprises: an optical device (60) configured to:

• generate an optical stimulus at a plurality of positions in the visual field (1) of the person,

• detect an eye reaction of the person in response to a positional change of the optical stimulus between positions, wherein the eye reaction is selected from one or more of a group consisting of: a change in size of a pupil and/or a saccade (30) and the computer (50) according to claim 28.