Apparatus and method for an eye movement test

Abstract

A small tool (10) for evaluating visual target tracking measures that can be used for an individual's eye movement test under various circumstances with neurological impairments. This tool comprises an elongated shaft (12) and a slide member (26) adapted to slide along the shaft. This tool can be used to perform one or more eye movement evaluations including smooth pursuit evaluation, convergence evaluation, saccade evaluation, and vestibulo-ocular reflex evaluation.

Description

Related Applications

[0001] Cross - References to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 353,122, filed on June 17, 2022, which is hereby incorporated by reference in its entirety.

Technical Field

[0002] Embodiments of the present invention relate to a small tool for evaluating visual target - tracking metrics that can be used for the eye movement testing of an individual under various circumstances involving neurological disorders. Examples of these disorders include concussion suspicion, acute neurological disorders, poisoning, etc., which may impair post - injury visual tracking.

Background Art

[0003] There is currently no standardized evaluation method for the eye evaluation of patients suspected of and / or confirmed to have neurological disorders. Although many new products using artificial intelligence (AI) and other electronic measurement means have been manufactured, an evaluation tool for assessing four major vestibulo - oculomotor skills that can be easily portable and does not require electronic means or an Internet connection has not yet been established. These evaluations are required for various neurological conditions, especially concussions.

[0004] There is an increasing awareness of the long - term health effects of repeated head trauma, such as those that can occur in sports activities. Therefore, healthcare providers highly value identifying concussion suspicion and keeping patients away from further activities until concussion can be confirmed by healthcare providers. The diagnosis of concussion can be a subjective exercise that often depends on the skills and expertise of medical professionals observing eye movements. Medical professionals often use various cognitive and motor function tests to evaluate brain function before and after head injury and make a diagnosis based on the results of those tests.

[0005] Eye movement examinations are not standardized in the medical community with a specific tool and can be performed using various evaluation tools. The lack of a standardized test can lead to inaccurate diagnoses of concussion and other neurological conditions, which increases the possibility that a patient with a neurological disorder may be permitted to resume activities or that a patient with an uninjured nerve may be unnecessarily kept away from activities for a certain period of time.

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, there is a need in the art for a standardized eye movement evaluation tool that can be used to perform various evaluations to more accurately screen for neurological deficits in patients suspected of having a disorder.

[0007] As described above, eye movement tests can be used in other applications beyond the evaluation of traumatic injuries. For example, eye movement tests can be used to screen for other vestibular disorders that can be the result of congenital defects or poisoning. Specifically, alcohol intoxication can result in vestibular disorders that can be detected by eye movement evaluations. A standardized tool that can be used by law enforcement agencies or other first responders can help, for example, to evaluate the impairment of an individual suspected of driving a motor vehicle in a poisoned state.

Means for Solving the Problems

[0008] According to one embodiment of the present invention, an eye movement evaluation tool is provided that includes an elongated shaft with graduations. The elongated shaft includes a proximal end adapted to be positioned in contact with the patient's nose during use. The tool further includes a slide member adapted to slide along at least a portion of the length of the elongated shaft. The position of the slide member on the shaft is recorded by its location relative to the shaft graduations. A tab is connected to the slide member and is slidable therewith. The tab is configured to extend upwardly from the slide member. When the proximal end is positioned in contact with the patient's nose and the shaft is extended horizontally away from the patient's head, the tab has a surface observable by the patient. The tab surface includes a first fixation character positioned substantially horizontally relative to the patient's eye.

[0009] According to another embodiment of the present invention, a method for screening a patient's eye movements, particularly when screening for possible concussion, is provided. The method includes first providing an eye movement evaluation tool according to any of the embodiments described herein. Preferably, the evaluation tool is then extended from a folded configuration to an extended configuration. One or more eye movement evaluations are then performed using the evaluation tool selected from the group consisting of a smooth pursuit evaluation, a convergence evaluation, a saccade evaluation, and a vestibulo-ocular reflex evaluation.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0016] The drawings do not necessarily provide exact dimensions or tolerances for the illustrated components or structures, but the drawings are to scale with respect to the relationships between the components of the structures shown in the drawings.

[0017] Referring to FIGS. 1-6, an eye movement evaluation tool 10 is shown. The tool 10 includes an elongated shaft 12. In one or more preferred embodiments, the elongated shaft includes at least two foldable segments 14, 16. However, it is within the scope of the present invention for the shaft to be a one-piece integral structure. In a preferred embodiment, the tool also includes a nose piece 18 that includes at least one outer surface 20 configured to conform to the patient's nose, as particularly seen in FIGS. 5 and 6. However, the elongated shaft 12 may simply be provided with a blunt end configured to be positioned to engage the patient's nose. The segments 14, 16 may be connected to each other by a tether 22 that can be an elastic cord (or other material) such that the two segments are always fixed together. Alternatively, the segments 14, 16 may be removable from each other for storage when the tool 10 is not in use. The segments 14, 16 may each include mating ends 15, 17 to assist in fixing the segments together. For example, as shown, the mating ends 15, 17 may include male and female connection structures configured to be fixed together by friction. Alternatively, the ends 15, 17 may include, for example, a screw connection or a spring-loaded pin and hole connection. The elongated shaft 12 may be graduated to indicate the distance from the patient's nose when the tool is in use. The graduations 24 may be in the form of graduation marks that preferably include numerical values assigned to some or all of the graduation marks in centimeters.

[0018] Tool 10 further includes a slide member 26 adapted to slide along at least a portion of the length of the elongated shaft 12. The position of the slide member 26 on the shaft 12 is indicated by its location relative to the shaft scale 24. The tool 10 further includes a tab 28 connected to the slide member 26 and slidable therewith. The tab 28 is configured to extend upwardly from the slide member 28 as shown in FIGS. 3 and 4. The tab 28 has a tab surface 30 with a first focal character 32 located thereon. The focal characters described herein can include any distinguishable visual indicator that can be observed by a patient during use of the tool 10. In certain embodiments, the focal characters can include letters, numbers, symbols, shapes, objects, images, colors, patterns, or any combination thereof. The focal characters should be selected to be readily identifiable in relation to the other structures of the tool 10 and, in certain embodiments, readily distinguishable from one another. In one or more embodiments, the focal characters described herein have a font size of 12 to 16 points, preferably 14 points (1 point is equal to 1 / 72 of an inch).

[0019] In certain embodiments, the slide member 26 includes a window 42 through which the shaft scale 24 can be viewed.

[0020] The nose piece 18 includes a side wall surface 34 that is disposed laterally from the outer surface 20 and has a second focus character 36 located thereon. As shown in FIGS. 1-6, the second focus character 36 includes a circle, although this character can be any type of character as described above. In a particular embodiment, as seen in FIG. 5, a third focus character 44 can be provided at the opposite end of the second focus character 36, i.e., at the distal end of the device 10. The third focus character 44 is shown as including a square, although it can be any type of focus character as described above. Preferably, the second focus character 36 and the third focus character 40 are located on the same general side of the tool 10 such that the focus characters can be seen simultaneously without the need to reorient the tool within the user's field of view. Also, the second focus character 36 and the third focus character 44 are preferably complementary to each other, i.e., both are shapes, both are letters, both are numbers, etc., although this is not always necessary. Also, the two focus characters are preferably different from each other (i.e., a square and a circle, the numbers 3 and 5 (non-repeating characters)) to help explain the test to be performed on the patient.

[0021] Further, the slide member 26 includes a side wall surface 38 having yet another focus character 40 located thereon. As shown, the focus character 40 includes an arrow and the word "slide". In addition to providing a simple indication regarding device operation, the focus character 40 can be used in the same manner as the third focus character 44 since the focus character 40 can potentially obscure the third focus character 44 when the slide member 26 is disposed in its most distal position. Thus, the focus character 40 can be any type of focus character as described above.

[0022] The tool is shiftable between a folded configuration as shown in FIG. 1 and an extended configuration as shown in FIG. 3. When in the folded configuration, the slide member 26 is disposed adjacent to the nose piece 18. In certain embodiments, the slide member 26 may be adapted to engage and / or couple with the nose piece 18 to inhibit relative movement between the two segments 14, 16 when in the folded configuration. The two segments 14, 16 may also be configured such that one segment is received nested within the other of the segments when in the folded configuration.

[0023] In certain embodiments, as shown in FIGS. 5 and 6, when the outer surface 20 is disposed in contact with the patient's nose and the shaft 12 is horizontally extended away from the patient's head, the tab surface 30 and the first focal character 32 are in a face-to-face relationship with the patient's face, and the first focal character 32 is positioned generally horizontally relative to the patient's eyes or slightly below the patient's eyes. In the extended position, the tab 28 extends upwardly from the slide member 26. In the folded configuration, the tab 28 is shifted to a storage configuration in which the tab 28 extends toward the nose piece 18.

[0024] As described in more detail below, the tool is configured to be used when performing one or more eye movement evaluations, including smooth pursuit evaluation, convergence evaluation, saccade evaluation, and vestibulo-ocular reflex (VOR) evaluation. It is understood that both saccade evaluation and VOR evaluation include a horizontal evaluation component and a vertical evaluation component. These tests can be performed in the order described or in any other order recommended by a medical professional. In addition to the generalized use of the tool for these evaluations, when used in cases where there is suspicion of concussion, these measurements can be used to assist in screening for concussion and evaluating recovery. This tool can also be used to perform a baseline evaluation on a patient prior to experiencing a head injury, and thus, for example, when there is suspicion of concussion in a patient, those baseline evaluations can be referenced to more accurately screen for concussion. Further, the tool can be used to screen for eye movement disorders that may result from any neurological disorder.

[0025] Embodiments of the eye movement evaluation tool can be used to perform one or more eye movement evaluations to assist in screening for vestibular disorders, such as concussion, although not limited thereto. These tests include convergence evaluation, smooth pursuit evaluation, saccade evaluation, and vestibulo-ocular reflex evaluation.

[0026] Evaluation of Convergence Convergence is the visual response induced by interest in nearby objects, i.e., the simultaneous inward movement of both eyes relative to each other, which normally maintains single binocular vision when looking at an object. In a convergence assessment, an appropriate distance from the patient's eyes for performing additional assessments is determined. For a convergence test, the slider is set to the marked scale that is farthest from the patient's face. In the figure, this is the 20 cm mark. The nose piece of the tool is then placed on the patient's nose, as shown, for example, in FIGS. 5 and 6. The patient may assist in placing and holding the tool throughout the examination. The slider, which has an upwardly extending tab with a fixation character thereon, is moved slowly towards the patient's face until the patient reports double vision, a blurred field of view while looking at the fixation character, or the healthcare provider notices that the eyes move asymmetrically inward. The location of the slider is then preferably recorded in centimeters using the scale. In certain embodiments, an abnormal result may be reported if the slider is located at a scale greater than 6 cm at the end of the examination. As shown, the fixation character can be a letter such as a capital "E", similar to what is displayed on a standard visual acuity chart. However, any fixation character (e.g., letter, number, shape, object, etc.) can be used.

[0027] Evaluation of Smooth Pursuit Smooth pursuit movement is a slower tracking movement of the eyes in which the eyes remain fixed on a moving object. The evaluation is designed to maintain a moving stimulus to the fovea, an area of the retina specialized for high acuity that is at the center of the macula and contains a high density of cones and a small number of rods. It is one of two ways in which a visual animal can voluntarily shift its line of sight. In smooth pursuit evaluation, any of the focus characters located on the device can be used as a moving object on which the patient's eyes should be fixed while the patient's head remains stationary. The evaluation tool is then held at the midline and eye height, further away from the patient's face than the convergence distance determined in the convergence evaluation. The evaluation tool is then moved horizontally (left and right) in front of the patient, and the full range of eye movements indicated by the eyes is evaluated. At the left and right end ranges, the tool is moved up and down (laterally, then up and down, then up and down on the opposite side) in an "H" movement. Optionally, the tool can be moved up and down at the midline to fully evaluate the eye movement range. Note whether there are small jumps in nystagmus at the ends of each range of eye movements (1 - 2 vibrations at the end or range are allowed). Note whether the eyes are moving symmetrically and whether the eyes can hold the edges or the eye range. Persistent nystagmus or more than 3 nystagmus will result in a failed evaluation. Note whether the patient has completed the symmetric movement range by turning the head. Generally, the evaluation is assessed by noting whether the patient's performance was "within normal range" or "outside normal range". The evaluation can be repeated until the examiner is confident in the accuracy of the evaluation findings.

[0028] Saccade evaluation Saccades are rapid ballistic movements of the eyes that change the fixation point abruptly. Their amplitudes range from small movements made, for example, during reading to much larger movements made while looking around a room. Saccades are spontaneously induced but can occur reflexively at any time when the eyes are open, even when fixed on a target. Saccadic eye movements are said to be ballistic because the saccade generation system cannot respond to subsequent changes in the position of the target during the course of the eye movement. If the target moves again during this time (which is on the order of 15 - 100 ms), the saccade misses the target and a second saccade has to be made to correct the error. Saccade evaluation can be performed in both the horizontal and vertical directions. The second and third fixation characters (e.g., a circle and a square) are facing the patient. In horizontal measurement, the elongated evaluation tool is oriented with its longitudinal axis substantially horizontal, far enough beyond the convergence distance determined in the convergence evaluation, preferably 2 - 3 feet away from the patient, and held in front of the patient's face. The patient is then asked to shift from looking at one fixation character to looking at the other while keeping the head stationary. The process can be repeated 2 - 4 cycles as needed to allow the examiner to be confident in the findings. The healthcare provider evaluates for hypo or hypermetric saccadic movements and records these findings. Vertical saccade evaluation is performed similarly, except that the evaluation tool is placed in front of the patient's face with its longitudinal axis substantially vertically oriented. The patient is then asked to shift from looking at one fixation character to looking at the other. The healthcare provider evaluates the patient for hypo or hypermetric saccadic movements and records these findings. The evaluation score is reported as "within normal range" or "outside normal range".

[0029] Evaluation of the vestibulo - ocular reflex The vestibulo-ocular reflex (VOR) is a reflex that acts to stabilize the line of sight during head movement. The eye movements during this reflex are caused by the activation of the vestibular system. The reflex acts to stabilize the image on the retina of the eye during head movement. The line of sight is stably maintained at a certain location by generating eye movements in the direction opposite to the head movement. For example, when the head moves to the right, the eyes move to the left, which means that the image a person sees remains the same even when the head rotates. Since there are always slight movements of the head, the VOR is necessary to stabilize vision. In VOR evaluation, any focal character located on the device can be used for this evaluation. The device is placed at a distance greater than the convergence distance determined during the convergence evaluation, preferably at a distance of about 2 - 3 feet in front of the patient, at eye level and at the center of the patient's visual field. The device is statically held in front of the patient.

[0030] The evaluation has two stages: the yaw movement stage and the pitch movement stage. In the yaw movement stage, the patient is asked to move the head from left to right as if providing a non-verbal "no" movement (i.e., shaking the head from side to side) while focusing on the focal character. The frequency of this movement should be about 120 times per minute while the patient is in a standing position and focusing on the focal character. The patient continues this yawing movement until the patient reports experiencing dizziness or loss of balance, or other adverse effects. The healthcare provider records the number of seconds the patient was able to endure the yawing movement before experiencing adverse effects. In the pitch movement stage, the patient is asked to move the head up and down as if providing a non-verbal "yes" movement (i.e., shaking the head up and down). The frequency of this movement should be about 120 times per minute while the patient is in a standing position and focusing on the focal character. The patient continues this pitching movement until the patient reports experiencing dizziness or loss of balance, or other adverse effects. The healthcare provider records the number of seconds the patient was able to endure the pitching movement before experiencing adverse effects. If each movement stage can be endured for 120 seconds without losing balance, the patient is considered to have passed the evaluation.

Claims

**Claim 1** An eye movement evaluation tool, comprising a graduated elongated shaft including a proximal end configured to be disposed in contact with the patient's nose, a slide member adapted to slide along at least a portion of the length of the elongated shaft, wherein the position of the slide member on the shaft is recorded by the location of the slide member relative to the shaft graduations, a tab connected to the slide member and slidable therewith, the tab being configured to extend upwardly from the slide member, having an outer surface configured to be disposed in contact with the patient's nose, and having a surface observable by the patient when the shaft extends horizontally away from the patient's head, and the eye movement evaluation tool, wherein the tab surface comprises a first focus character positioned substantially horizontally relative to the patient's eye. **Claim 2** The eye movement evaluation tool according to claim 1, wherein the proximal end comprises a nose piece having an outer surface configured to conform to the patient's nose. **Claim 3** The eye movement evaluation tool according to claim 2, wherein the nose piece includes a side wall surface disposed laterally from the at least one outer surface, the side wall surface comprising a second focus character positioned thereon. **Claim 4** The eye movement evaluation tool according to claim 3, wherein the slide member comprises a side wall surface having a third focus character positioned thereon, the second focus character and the third focus character being positioned on the same side of the tool and spaced apart from each other. **Claim 5** The eye movement evaluation tool according to claim 1, wherein the slide member comprises a window through which the shaft graduations can be viewed. **Claim 6** The eye movement evaluation tool according to claim 1, wherein the tool is foldable into at least two segments. **Claim 7** The eye movement evaluation tool according to claim 6, wherein the at least two segments are connected by a tether. **Claim 8** The eye movement evaluation tool according to claim 6, wherein the tool is shiftable between a folded configuration and an extended configuration. **Claim 9** The eye movement evaluation tool according to claim 8, wherein in the folded configuration, the slide member is disposed adjacent to the proximal end. **Claim 10** The eye movement evaluation tool according to claim 9, wherein the slide member is configured to engage and connect with the proximal end to prevent relative movement between the at least two segments.

11. The tab is configured to extend upward from the slide member when the tool is in the extended configuration, and the tab is in a storage configuration that extends downward toward the proximal end when the tool is in the folded configuration. The eye movement evaluation tool according to claim 8.

12. The eye movement evaluation tool according to claim 6, wherein the at least two segments are configured such that one of the segments can be received in a nested manner within the other of the segments.

13. The eye movement evaluation tool according to claim 1, wherein the tool is configured to be used when performing one or more eye movement evaluations selected from the group consisting of smooth pursuit evaluation, convergence evaluation, saccade evaluation, and vestibulo-ocular reflex evaluation.

14. A method for screening a patient's eye movement, comprising: providing an eye movement evaluation tool according to any one of claims 1 to 13; performing one or more eye movement evaluations selected from the group consisting of smooth pursuit evaluation, convergence evaluation, saccade evaluation, and vestibulo-ocular reflex evaluation using the eye movement evaluation tool; and a method comprising.

15. The method according to claim 1, wherein the eye movement evaluation tool is foldable, and the method further comprises extending the eye movement evaluation tool from a folded configuration to an extended configuration before performing the one or more eye movement evaluations.

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