A method, system, and terminal for detecting visual field defects based on brain-computer interface

Abstract

This invention belongs to the field of visual field detection technology, and relates to a method for detecting visual field defects based on a brain-computer interface. The method includes: presenting isotopic stimuli to the subject's eyes, collecting EEG signals induced by multiple isotopic stimuli, and constructing EEG signal templates for each type; presenting symmetrical stimuli to the subject's eyes, and collecting EEG signals induced by multiple symmetrical stimuli; identifying two isotopic stimuli corresponding to each symmetrical stimulus, performing correlation analysis between the EEG signals induced by each symmetrical stimulus and the corresponding EEG signal templates induced by the two isotopic stimuli, and determining the presence of visual field defects based on the correlation analysis results; and further identifying the location of the visual field defect. This invention also discloses a visual field defect detection system and a terminal based on a brain-computer interface. This invention has advantages such as strong objectivity, less susceptibility to individual differences, simple operation, high detection efficiency and accuracy, low stimulus intensity, less subject fatigue, high comfort, and high spatial resolution.

Description

Technical Field

[0001] This invention relates to the field of visual field detection technology, and in particular to a method, system and terminal for detecting visual field defects based on a brain-computer interface. Background Technology

[0002] Glaucoma is a chronic degenerative disease of the optic nerve characterized by progressive visual field loss, marked by retinal ganglion cell death and optic nerve axon loss. It ultimately leads to permanent vision loss and even total blindness. Based on the angle of the anterior chamber, glaucoma can be divided into two main categories: open-angle and angle-closure. Open-angle glaucoma progresses slowly and often has no obvious symptoms in its early stages, frequently being discovered only in its later stages, making treatment more difficult and reducing the chance of a cure. Angle-closure glaucoma presents with acute attacks, accompanied by eye pain and rapid vision loss. Globally, open-angle glaucoma accounts for approximately 74% of all glaucoma cases. Many patients miss the optimal intervention window because they did not receive effective screening and treatment in the early stages. Therefore, accurate detection of visual field defects in the early stages of glaucoma is crucial, not only helping patients preserve their vision but also reducing the medical burden of late-stage glaucoma.

[0003] Traditional visual field testing methods include static threshold testing using a standard automated perimeter and visual electrophysiological testing using electroretinography (ERG). The static threshold testing method using a standard automated perimeter is a psychophysiological examination method that is highly dependent on the patient's subjective response and exhibits a significant learning effect. Subjects often need 2-3 tests to obtain consistent results. Therefore, this method is usually unable to detect subtle visual field defects in the early stages of the disease, and it is also demanding on patients and resource-intensive. The visual electrophysiological testing method using ERG is a relatively complex electrophysiological test that requires specialized equipment and highly trained technicians. The equipment is expensive, and maintenance and operation costs are high. Furthermore, this method also places high demands on patients: firstly, they need to sit still and fixate on a specific target for an extended period, which may be unsuitable for young children, those with intellectual disabilities, or other patients with difficulties in cooperation; secondly, it requires pupil dilation and local anesthesia, which may prevent some patients from using this method.

[0004] In recent years, diagnostic techniques combining brain-computer interfaces (BCIs) with visual field defect detection have matured. BCI is a method that uses neuroscience and engineering to directly measure brain activity and interpret its signals. Among these, non-invasive BCIs based on electroencephalography (EEG) offer advantages such as safety, non-invasiveness, and low cost, showing broad application prospects in clinical diagnosis. In EEG-based BCI systems, the paradigm of using visual evoked stimuli is commonly used, with SSVEP-BCI based on steady-state visual evoked potentials (SSVEP) being the most typical. However, the visual stimuli used to evoke SSVEP often flicker intensely, easily causing visual fatigue and limiting its use over extended periods. Furthermore, SSVEP-BCI has low spatial resolution, only detecting visual field defects at missing frequency components but failing to delineate the precise contours of the defective area.

[0005] In view of the above problems, there is an urgent need to propose a visual field detection method that does not require high costs, does not limit the detection population, is not prone to causing visual fatigue, and has high detection sensitivity. Summary of the Invention

[0006] The purpose of this invention is to provide a method, system, and terminal for visual field defect detection based on a brain-computer interface. This method utilizes a non-invasive electrode to collect electroencephalogram (EEG) signals, eliminating the need for additional auxiliary drugs or tools and not limiting the target population. During the detection process, subtle visual stimuli are presented to the subject within their peripheral visual field, providing a comfortable visual experience and minimizing visual fatigue.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a visual field defect detection method based on a brain-computer interface, comprising:

[0009] S1. Present isotopic stimuli to the subject's eyes, collect EEG signals induced by multiple isotopic stimuli, and construct EEG signal templates for each type.

[0010] S2. Present symmetrical stimuli to the subject's eyes and collect the electroencephalogram (EEG) signals induced by multiple symmetrical stimuli;

[0011] S3. Identify the two isotopic stimuli corresponding to each symmetrical stimulus, perform correlation analysis between the EEG signal induced by each symmetrical stimulus and the EEG signal templates induced by the two isotopic stimuli respectively, and determine whether there is visual field defect based on the correlation analysis results.

[0012] S4. Identify the locations where there are visual defects.

[0013] As one possible implementation, both isotopic stimuli and symmetrical stimuli are flashing light spots located in two identical images presented to the left and right eyes respectively. When isotopic stimuli are presented to both eyes of the subject, the flashing light spot presented in the left eye image and the flashing light spot presented in the right eye image are in the same position on both images. When symmetrical stimuli are presented to both eyes of the subject, the flashing light spot presented in the left eye image and the flashing light spot presented in the right eye image are centrally symmetrical about the center of the overlapping images, or axially symmetrical about the horizontal axis of the center, or axially symmetrical about the vertical axis of the center.

[0014] As one possible implementation, each symmetrical stimulus corresponds to two isotopes: an isotope that is at the same position as the blinking point of the symmetrical stimulus presented in the left eye image, and an isotope that is at the same position as the blinking point of the symmetrical stimulus presented in the right eye image.

[0015] As one possible approach, determining the presence of visual field defects based on correlation analysis results includes:

[0016] The correlation between the EEG signal induced by each symmetrical stimulus and the EEG signal template induced by the two corresponding isotopic stimuli was analyzed one by one. If there is no correlation between the EEG signal induced by one or more symmetrical stimuli and the EEG signal template induced by the two corresponding isotopic stimuli, it is determined that there is a defect in both visual fields.

[0017] If the EEG signal induced by one or more symmetrical stimuli is only correlated with the EEG signal template induced by one of the isotopic stimuli, then it is determined that there is a defect in the visual field of one eye.

[0018] Otherwise, determine that there is no visual field defect in both eyes.

[0019] As one possible approach, the following method is used to determine the locations with visual defects:

[0020] When it is determined that there are visual field defects in both eyes, the eccentricity of the location of the visual field defect on the retina is calculated based on the position of the uncorrelated isotopic stimulus in the picture to determine the location of the visual field defect on the retina.

[0021] When determining if there is a visual field defect in one eye, the following method is used to identify the location of the visual field defect:

[0022] If there is only a correlation with the EEG signal template induced by the isotopic stimulus in the left eye, then there is a visual field defect in the right eye. The eccentricity of the location of the visual field defect on the right retina is calculated based on the position of the isotopic stimulus in the right eye image to determine the location of the visual field defect on the right retina.

[0023] If the EEG signal template induced only by the isotopic stimulus in the right eye is correlated, then there is a visual field defect in the left eye. The eccentricity of the location of the visual field defect on the left retina is calculated based on the position of the isotopic stimulus in the left eye image to determine the location of the visual field defect on the left retina.

[0024] As one possible approach, isotopic and symmetrical stimuli are identical in size, color, shape, and flashing frequency.

[0025] As one possible implementation, the stimulus size is a visual angle of less than 0.2°, and / or the flicker frequency is 0.5 to 20 Hz.

[0026] As one possible approach, when presenting isotopic or symmetrical stimuli to the subject's eyes, the subject does not look at the presented isotopic or symmetrical stimuli, but only looks at the center of the image directly in front of their eyes.

[0027] In a second aspect, the present invention provides a visual field defect detection system based on a brain-computer interface, used to execute the visual field defect detection method based on a brain-computer interface provided in the first aspect, comprising:

[0028] Stimulus presentation device, which presents visual stimuli to the user's two eyes through two independent display areas;

[0029] EEG acquisition equipment is used to collect the EEG signals of subjects, amplify and filter the EEG signals to form EEG data, and send it to data processing equipment;

[0030] The data processing equipment is used to construct templates for each type of EEG signal induced by isotopic stimuli, and to determine the two isotopic stimuli corresponding to each symmetrical stimulus. Correlation analysis is performed between the EEG signal induced by each symmetrical stimulus and the EEG signal templates induced by the corresponding two isotopic stimuli.

[0031] The test result output device is used to generate visual field defect detection results based on correlation analysis results.

[0032] Thirdly, the present invention provides a terminal including a processor and a communication interface coupled to the processor, the processor being used to run computer programs or instructions to implement the visual field defect detection method based on brain-computer interface provided in the first aspect.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. The visual field defect detection method based on brain-computer interface proposed in this invention designs a visual stimulation paradigm and reflects the visual field status through electroencephalogram signals. Compared with the detection method based on traditional perimeter, it is more objective and less affected by individual differences.

[0035] 2. The visual field defect detection method based on brain-computer interface proposed in this invention presents stimulation to both eyes of the user and uses an EEG acquisition device to collect EEG signals. Compared with the traditional perimeter-based method that requires detection under the condition of monocular occlusion and the electroretinogram-based method, this method simplifies the operation of the detection process, improves detection efficiency, and reduces subject fatigue, making the subject more comfortable.

[0036] 3. The visual field defect detection method based on brain-computer interface proposed in this invention uses visual stimulation with low stimulation intensity and high spatial resolution. The stimulation is located in the peripheral visual field, and the subject does not need to look directly at the stimulation, which can improve the comfort of visual stimulation. In addition, the stimulation size is small, occupying a visual angle of less than 0.2°, which can achieve high detection spatial resolution.

[0037] 4. The brain-computer interface-based visual field defect detection method proposed in this invention can improve the detection accuracy of different visual field states by constructing a training template and using supervised machine learning algorithms for correlation analysis. Attached Figure Description

[0038] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0039] Figure 1 This is a flowchart of the visual field defect detection method based on brain-computer interface in an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of isotopic stimulation in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of symmetrical stimulation in an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of the distribution of visual stimulus points in an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of two isotopic stimuli corresponding to one symmetrical stimulus in an embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of the square wave scintillation sequence of the stimulus in an embodiment of the present invention;

[0045] Figure 7 This is a temporal diagram of isotopic stimuli in an embodiment of the present invention;

[0046] Figure 8 This is a schematic diagram of the visual field defect detection system based on brain-computer interface in an embodiment of the present invention.

[0047] Figure Labels

[0048] 1-Stimulation presentation device, 2-EEG acquisition device, 3-Data processing device, 4-Detection result output device. Detailed Implementation

[0049] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0050] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0051] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c" can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0052] This invention aims to provide a method, system, and terminal for visual field defect detection based on a brain-computer interface. The method utilizes a non-invasive electrode to acquire electroencephalogram (EEG) signals, eliminating the need for additional auxiliary drugs or tools and not limiting the target population. During the detection process, subtle visual stimuli are presented to the subject within their peripheral visual field, providing a visually friendly experience and minimizing visual fatigue.

[0053] In a first aspect, embodiments of the present invention provide a visual field defect detection method based on a brain-computer interface, see [link to relevant documentation]. Figure 1 It includes the following steps:

[0054] S1. Present isotopic stimuli to the subject's eyes, collect EEG signals induced by multiple isotopic stimuli, and construct EEG signal templates for each type.

[0055] See Figure 2 As one possible implementation, the isotopic stimulus is a blinking light dot located in two identical images presented to the left and right eyes respectively. When the isotopic stimulus is presented to both eyes, the blinking light dot presented to the left eye is in the same position as the blinking light dot presented to the right eye in both images. In practice, the subject wears a VR device, which presents visual stimuli to the user's two eyes through two independent display areas. The isotopic stimulus induces asymmetric visual evoked potential (aVEP) EEG signals in a single spatial pattern. Since the types of EEG signals evoked by stimuli presented at different locations in the eyes are different, it is necessary to collect EEG signals evoked by the isotopic stimulus multiple times in practical applications. Then, the collected EEG signals evoked by the isotopic stimulus are preprocessed and feature extracted to construct a template for each type of EEG signal.

[0056] S2. Present symmetrical stimuli to the subject's eyes and collect the electroencephalogram (EEG) signals induced by multiple symmetrical stimuli;

[0057] See Figure 3One possible implementation involves symmetrical stimuli, which are flashing light points located in two identical images presented to the left and right eyes respectively. When the symmetrical stimulus is presented to both eyes, the flashing light points displayed to the left and right eyes are centrally symmetrical about the center of the overlapping images, or axially symmetrical about the horizontal or vertical axis of the center. In practice, the subject wears a VR device, which presents visual stimuli to each eye through two independent display areas. The symmetrical stimulus induces asymmetric visual evoked potential (aVEP) EEG signals, which fuse the features of two spatial patterns. In practical applications, it is also necessary to collect EEG signals evoked by the symmetrical stimulus multiple times to enhance the signal-to-noise ratio and improve the accuracy of the final detection results.

[0058] The horizontal visual field of a single eye is approximately 150°, with a nasal visual field of 60° and a temporal visual field of 90–100°. The maximum horizontal visual field of both eyes can reach 188°, of which the binocular overlapping visual field is 124°. The visual field of general visual field testing does not exceed 60°, all of which is included within the binocular overlapping visual field. Therefore, traditional testing methods must be performed with one eye occluded, making it impossible to test both eyes simultaneously. This new method provides visual stimulation to both eyes throughout the entire process, simplifying the testing procedure, reducing subject fatigue, and enabling simultaneous binocular testing.

[0059] As one possible implementation, when presenting isotopic or symmetrical stimuli to the subject's eyes, the subject does not gaze at the presented isotopic or symmetrical stimuli, but only at the center of the image directly in front of their eyes. The isotopic and symmetrical stimuli are identical in size, color, shape, and flicker frequency. For example, the stimulus size is less than 0.2° in visual angle, and / or the flicker frequency is 0.5–20 Hz, such as 0.5 Hz, 1 Hz, 4 Hz, 8 Hz, 12 Hz, 16 Hz, or 20 Hz.

[0060] See Figure 4 The visual angle of the stimulus presented in this embodiment is less than 0.2°, so theoretically the spatial resolution can reach a maximum visual angle of 0.2°. Figure 4 The central "+" symbol represents the target displayed at the center of the screen directly in front of the subject's eyes, while the surrounding white dots represent the visual stimuli. In this embodiment, 54 points are set within a 24° field of view at the center. During actual testing, only one white dot appears on a single screen at any given time.

[0061] Existing detection technologies, such as those using electroretinography (ERG), require a high degree of patient cooperation, such as prolonged sitting and fixation on a specific target. In this protocol, the subject only needs to focus on the center of the image, without direct visual stimulation, and the presented stimulation is minimal, which reduces subject fatigue and improves visual stimulation comfort.

[0062] It should be noted that, in addition to presenting two flashing stimuli simultaneously as proposed in this embodiment, any number of flashing stimuli can be presented simultaneously with the midpoint of the line connecting the visual centers of both eyes as the origin, and can be used as visual stimuli in this solution. Furthermore, this solution has no fixed requirements on the color or shape of the flashing stimuli; flashing light spots of any color and shape will not affect the achievement of the effect of this solution.

[0063] S3. Identify the two isotopic stimuli corresponding to each symmetrical stimulus, perform correlation analysis between the EEG signal induced by each symmetrical stimulus and the EEG signal templates induced by the two isotopic stimuli respectively, and determine whether there is visual field defect based on the correlation analysis results.

[0064] See Figure 5 As one possible implementation, each symmetrical stimulus corresponds to two isotopes: an isotope that is at the same position as the blinking point of the symmetrical stimulus in the left eye image, and an isotope that is at the same position as the blinking point of the symmetrical stimulus in the right eye image.

[0065] As one possible approach, determining the presence of visual field defects based on correlation analysis results includes:

[0066] The correlation between the EEG signal induced by each symmetrical stimulus and the EEG signal template induced by the two corresponding isotopic stimuli was analyzed one by one. If there is no correlation between the EEG signal induced by one or more symmetrical stimuli and the EEG signal template induced by the two corresponding isotopic stimuli, it is determined that there is a defect in both visual fields.

[0067] If the EEG signal induced by one or more symmetrical stimuli is only correlated with the EEG signal template induced by one of the isotopic stimuli, then it is determined that there is a defect in the visual field of one eye.

[0068] Otherwise, determine that there is no visual field defect in both eyes.

[0069] S4. Identify the locations where there are visual defects.

[0070] As one possible approach, the following method is used to determine the locations with visual defects:

[0071] When it is determined that there are visual field defects in both eyes, the eccentricity of the location of the visual field defect on the retina is calculated based on the position of the uncorrelated isotopic stimulus in the picture to determine the location of the visual field defect on the retina.

[0072] When determining if there is a visual field defect in one eye, the following method is used to identify the location of the visual field defect:

[0073] If there is only a correlation with the EEG signal template induced by the isotopic stimulus in the left eye, then there is a visual field defect in the right eye. The eccentricity of the location of the visual field defect on the right retina is calculated based on the position of the isotopic stimulus in the right eye image to determine the location of the visual field defect on the right retina.

[0074] If the EEG signal template induced only by the isotopic stimulus in the right eye is correlated, then there is a visual field defect in the left eye. The eccentricity of the location of the visual field defect on the left retina is calculated based on the position of the isotopic stimulus in the left eye image to determine the location of the visual field defect on the left retina.

[0075] The technical solution of the present invention will be further explained below with reference to specific implementation strategies.

[0076] Phase 1: Acquisition of EEG signals induced by isotopic stimulation. Subjects wore EEG acquisition devices, and VR headsets presented subjects with isotopic stimuli at different locations. (See [link to documentation]). Figure 6 The flashing sequence of stimuli on the display is represented by a square wave, with the horizontal axis representing the frame rate and the vertical axis representing the normalized luminous intensity. A brightness of 1 indicates the stimulus is on, and a brightness of 0 indicates the stimulus is off. The refresh rate of the VR headset is set to 60Hz, and the flashing duration of a single visual stimulus is 0.25s, meaning it flashes at a frequency of 4Hz per cycle with a duty cycle of approximately 50%, resulting in 8 frames on and 7 frames off. See the stimulus timing diagram for details. Figure 7 A single visual stimulus constitutes a trial, and eight consecutive trials constitute a segment, lasting 2 seconds. After a segment ends, all stimuli in the center of the screen disappear, and the subject rests briefly for 1 second. Each trial presents one of N random visual stimuli, with the same number of trials for each stimulus. Each visual stimulus is distinguished by a unique label. When a stimulus illuminates, the VR headset sends the label to the EEG amplifier to pinpoint the time. A total of N types of EEG labels are obtained.

[0077] The template construction process includes data preprocessing, feature extraction, and EEG template construction. Data preprocessing includes downsampling filtering and baseline removal. Feature extraction can employ common EEG signal feature extraction algorithms such as Task-Related Component Analysis (TRCA) and Discriminative Spatial Pattern (DSP), and spatial filters are calculated. After multiple trials and averaging, spatial filtering yields the EEG template, resulting in N types of EEG signal templates.

[0078] Phase Two: Acquiring EEG signals induced by symmetrical stimulation. See also... Figure 3 By constructing horizontal and vertical coordinate axes using the center of the overlapping two images, the monocular image plane can be divided into four quadrants. Assuming the number of stimuli located on the coordinate axes is n1, these stimuli are either symmetrical along the horizontal or vertical axis, resulting in n1 types of symmetrical stimuli. Assuming the number of stimuli located in the four quadrants is n2 (n1 + n2 = N), these stimuli are either symmetrical or symmetrical, resulting in 3n2 types of symmetrical stimuli. Therefore, in this embodiment, the visual stimuli from N points can constitute n1 + 3n2 types of symmetrical stimuli. The timing of the stimuli is the same as for the isotopic stimuli, but the number of trials for each type of symmetrical stimulus can be less than the number of trials set for isotopic stimuli. The number of EEG tags obtained in this stage is n1 + 3n2. This embodiment does not use points located on the coordinate axes, therefore only 3N types of tags are needed.

[0079] Phase 3: Visual Field Defect Detection. The EEG signals acquired in Phase 2 are preprocessed and feature extracted using the same methods as in Phase 1. Then, the two isotopic stimuli corresponding to each symmetrical stimulus are identified. The EEG signal templates for these two isotopic stimuli constructed in Phase 1 are retrieved. Correlation analysis is performed between the symmetrical stimulus and these two EEG signal templates. If there is no visual field defect in the visual field area corresponding to the symmetrical stimulus point, the induced EEG exhibits characteristics of two spatial patterns and is correlated with both isotopic stimulus templates. If there is a visual field defect in one of the visual field areas corresponding to the symmetrical stimulus point, the induced EEG exhibits characteristics of a single spatial pattern and is correlated with one isotopic stimulus template but not with the other.

[0080] The visual field defect detection method based on brain-computer interface proposed in this invention designs a visual stimulation paradigm and reflects the visual field status through electroencephalogram signals. Compared with the detection method based on traditional perimeter, it is more objective and less affected by individual differences.

[0081] Secondly, embodiments of the present invention provide a visual field defect detection system based on a brain-computer interface, used to execute the visual field defect detection method based on a brain-computer interface provided in the first aspect, see [link to previous section]. Figure 8 The visual field defect detection system based on brain-computer interface includes a stimulus presentation device 1, an electroencephalogram (EEG) acquisition device 2, a data processing device 3, and a detection result output device 4.

[0082] The stimulus presentation device 1 presents visual stimuli to the user's two eyes through two independent display areas; in this embodiment, the stimulus presentation device 1 can be a virtual reality or augmented reality display device, or any other form of reality device capable of presenting images to the eyes separately.

[0083] EEG acquisition device 2 is used to acquire the subject's EEG signals, amplify and filter the EEG signals to form EEG data, and send it to data processing device 3. This embodiment does not limit the type of acquisition electrodes used in EEG acquisition device 2; wet electrodes, dry electrodes, saline electrodes, etc., can all be used. Electrodes can be integrated into wearable devices, such as deployed on VR display devices, or can be used as an EEG cap worn independently on the user's head or other forms. Stimulation presentation device 1 and EEG acquisition device 2 can communicate via wired / wireless means to transmit tag information and mark the stimulation start time.

[0084] Data processing device 3 is used to construct EEG signal templates for each type induced by isotopic stimuli, and to determine the two isotopic stimuli corresponding to each symmetrical stimulus. Correlation analysis is performed between the EEG signal induced by each symmetrical stimulus and the EEG signal templates induced by the corresponding two isotopic stimuli. Detection result output device 4 outputs visual field defect detection results based on the correlation analysis results. EEG data can be transmitted between EEG acquisition device 2 and data processing device 3 via wired / wireless means.

[0085] Specifically, visual stimuli are presented to the subject through stimulus presentation device 1. Different modalities of EEG encoding are performed using the visual stimulus paradigm of this scheme, stimulating different visual field points to comprehensively examine the entire peripheral visual field. EEG signals are collected by EEG acquisition device 2 and integrated with tags sent by stimulus presentation device 1, then transmitted to data processing device 3 for preprocessing, feature extraction, and pattern recognition. Stimulus-evoked signal templates for multiple visual field points are established, and the presence of visual field defects at each point is determined. Finally, result output device 4, combining patient information and physician diagnosis, provides a complete test result.

[0086] The actual hardware form, communication connection method, data processing flow or software form used do not affect the technical essence of the present invention.

[0087] Thirdly, the present invention provides a terminal including a processor and a communication interface coupled to the processor, the processor being used to run computer programs or instructions to implement the visual field defect detection method based on brain-computer interface provided in the first aspect.

[0088] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, the disclosure, and the description of the drawings, in carrying out the claimed invention. In this specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several of the functions listed in the specification. While certain measures are described in different embodiments, this does not mean that these measures cannot be combined to produce good results.

[0089] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications fall within the scope of the invention and its equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. A method for detecting visual field defects based on a brain-computer interface, characterized in that, include: S1. Present isotropic stimuli to the subject's eyes, collect EEG signals induced by multiple isotropic stimuli, and construct EEG signal templates for each type; S2. Present symmetrical stimuli to the subject's eyes and collect EEG signals induced by multiple symmetrical stimuli. Both isotopic and symmetrical stimuli are flashing dots located in two identical images presented to the left and right eyes respectively. When the isotopic stimulus is presented to the subject's eyes, the flashing dots presented in the left eye image and the flashing dots presented in the right eye image are in the same position on both images. When the symmetrical stimulus is presented to the subject's eyes, the flashing dots presented in the left eye image and the flashing dots presented in the right eye image are centrally symmetrical about the center of the overlapping images, or axially symmetrical about the horizontal axis of the center, or axially symmetrical about the vertical axis of the center. S3. Identify the two isotopic stimuli corresponding to each symmetrical stimulus, perform correlation analysis between the EEG signal induced by each symmetrical stimulus and the EEG signal templates induced by the two isotopic stimuli respectively, and determine whether there is visual field defect based on the correlation analysis results. Determining the presence of visual field defects based on correlation analysis results includes: The correlation between the EEG signal induced by each symmetrical stimulus and the EEG signal template induced by the two corresponding isotopic stimuli was analyzed one by one. If there is no correlation between the EEG signal induced by one or more symmetrical stimuli and the EEG signal template induced by the two corresponding isotopic stimuli, it is determined that there is a defect in both visual fields. If the EEG signal induced by one or more symmetrical stimuli is only correlated with the EEG signal template induced by one of the isotopic stimuli, then it is determined that there is a defect in the visual field of one eye. Otherwise, determine that there is no visual impairment in either eye. S4. Identify the locations where visual defects exist; The following method is used to identify locations with visual defects: When it is determined that there are visual field defects in both eyes, the eccentricity of the location of the visual field defect on the retina is calculated based on the position of the uncorrelated isotopic stimulus in the picture to determine the location of the visual field defect on the retina. When determining if there is a visual field defect in one eye, the following method is used to identify the location of the visual field defect: If there is only a correlation with the EEG signal template induced by the isotopic stimulus in the left eye, then there is a visual field defect in the right eye. The eccentricity of the location of the visual field defect on the right retina is calculated based on the position of the isotopic stimulus in the right eye image to determine the location of the visual field defect on the right retina. If the EEG signal template induced only by the isotopic stimulus in the right eye is correlated, then there is a visual field defect in the left eye. The eccentricity of the location of the visual field defect on the left retina is calculated based on the position of the isotopic stimulus in the left eye image to determine the location of the visual field defect on the left retina.

2. The visual field defect detection method based on brain-computer interface according to claim 1, characterized in that, Each symmetrical stimulus corresponds to two isotopes: one isotope that is at the same position as the blinking point of the symmetrical stimulus in the left eye image, and the other isotope that is at the same position as the blinking point of the symmetrical stimulus in the right eye image.

3. The visual field defect detection method based on brain-computer interface according to claim 1, characterized in that, The isotopic and symmetrical stimuli are identical in size, color, shape, and flashing frequency.

4. The visual field defect detection method based on brain-computer interface according to claim 3, characterized in that, The stimulation size is less than 0.2° in angle of view, and / or the flicker frequency is 0.5 to 20 Hz.

5. The visual field defect detection method based on brain-computer interface according to claim 1, characterized in that, When presented with isotopic or symmetrical stimuli to both eyes, the subjects do not fixate on the presented isotopic or symmetrical stimuli, but only focus on the center of the image directly in front of their eyes.

6. A visual field defect detection system based on a brain-computer interface, used to execute the visual field defect detection method based on a brain-computer interface as described in any one of claims 1 to 5, characterized in that, include: A stimulus presentation device that presents visual stimuli to the user's two eyes through two independent display areas; EEG acquisition equipment is used to collect the EEG signals of subjects, amplify and filter the EEG signals to form EEG data, and send it to data processing equipment; The data processing equipment is used to construct templates for each type of EEG signal induced by isotopic stimuli, and to determine the two isotopic stimuli corresponding to each symmetrical stimulus. Correlation analysis is performed between the EEG signal induced by each symmetrical stimulus and the EEG signal templates induced by the corresponding two isotopic stimuli. The test result output device is used to generate visual field defect detection results based on correlation analysis results.

7. A terminal, comprising a processor and a communication interface coupled to the processor, the processor being configured to run a computer program or instructions to implement the brain-computer interface-based visual field defect detection method according to any one of claims 1 to 5.

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