Assessing visual function
Methods, systems, and devices are provided for assessing visual function, especially in animals. For example, a device can be used for assessing visual functions, such as PLR and OMR, in animals that includes a visual stimulus unit. The device can also include one or more input devices that include at least one camera that is configured to monitor movement of the test subject and a processor that is configured to analyze the movement of the test subject taken by the camera and to assess visual functions of the test subject. The device can be used in a system including a designated general location for the test subject in which the test subject can see the visual stimulus unit and move freely while being monitored by the camera.
1. An assessment device for assessing visual functions of a test subject, comprising:
at least one processor, memory, a visual stimulus unit, a platform, and at least one input device, wherein the assessment device is formed to create an enclosed area defined at least by the platform providing an area for the test subject to i) stand on the platform during a testing procedure and ii) move freely during the testing procedure;
wherein the assessment device is configured to operate the testing procedure comprising:
receiving the test subject in the enclosed area on the platform;
displaying, using the visual stimulus unit, visual stimuli to the test subject on the platform in the enclosed area;
tracking head movement of the test subject, i) using the at least one input device and ii) while the visual stimuli is being displayed to the test subject on the platform in the enclosed area configured to monitor movement of the test subject comprising tracking a plurality of points of a head of the test subject, a first point being associated with a first ear of the test subject, and a second point being associated with a second ear of the subject, and a third point being associated with a snout of the test subject; and
determining a relationship between the head movement of the subject and the visual stimuli;
and wherein the assessment device is configured to determine if a head pausing count reaches one or more times a variable value before a head tracking movements count reaches the variable value,
wherein at which point the assessment device is configured to determine that the test subject cannot see the visual stimuli, and the processor is configured to set the visual stimuli at a higher contrast or at a lower spatial frequency.
2. The device of claim 1 , wherein the visual stimulus unit includes at least one display unit.
3. The device of claim 1 , wherein the input device includes at least one camera.
4. The device of claim 3 , wherein the camera includes an infrared camera.
5. The device of claim 1 , wherein the visual function includes acuity and contrast sensitivity.
6. The device of claim 1 , wherein the visual function includes photoreceptor cone or rod mediated function.
7. The device of claim 1 , wherein the visual stimuli include bars that change colors.
8. The device of claim 1 , wherein the visual stimuli include changing a lumen of the visual stimulus unit.
9. The device of claim 1 , wherein the visual stimuli include moving black and white bars at predefined widths and speeds and moving at a preset direction of either clockwise or counter-clockwise.
10. The device of claim 1 , wherein the visual stimulus unit includes one or more LCD screens configured to display rotating stripes, and the LCD screens all display black and white bars at a same predefined width moving in one simultaneous direction.
11. The device of claim 1 , wherein the processor is configured to assess contrast sensitivity and visual acuity by optomotor reflex protocol based on a head movement count and a staircase reversal count of the test subject.
12. The device of claim 11 , wherein the head movement count includes head tracking movements of the test subject and head pausing of the test subject.
13. The device of claim 12 , wherein head pausing of the test subject is configured to indicate that the test subject cannot see the visual stimuli.
14. The device of claim 11 , wherein the processor is configured to determine if a head tracking movements count reaches a variable value before a head pausing count reaches one or more times the variable value,
wherein at which point the processor is configured to determine that the test subject can see the visual stimuli, and the processor is configured to set the visual stimuli at a lower contrast or at a higher spatial frequency.
15. The device of claim 14 , wherein the processor is configured to determine if the head tracking movements count reaches the variable value before a head pausing count reaches 3 times the variable value.
16. The device of claim 1 , wherein the processor is configured to determine if the head pausing count reaches 3 times a variable value before a head tracking movements count reaches the variable value.
17. The device of claim 1 , wherein the input device includes a camera.
18. The device of claim 17 , wherein the camera includes an infrared camera.
19. The device of claim 1 , wherein the processor is configured to determine an orientation of a head of the test subject based on a contour extraction of the test subject, a point of maximum curvature on the contour of the test subject, and a computation from the point of maximum curvature and two side points that have equal distance from the point of maximum curvature along the contour.
20. The device of claim 1 , wherein the at least one input device is a camera positioned above the platform and oriented vertically such that the camera is capable of capturing images of the test subject in the enclosed area on the platform.