Eye Gaze Troubleshooting

Eye gaze cameras require specific positioning, and consistent access to the user's pupils. Glasses and dry eyes also have the potential to interfere with eye gaze.  It may be necessary to recalibrate the WinSlate from time to time, especially with significant positioning or ambient lighting changes.  

This article will provide some recommendations to ensure the best chances of eye gaze success.

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Positioning 

User Positioning

• Positioning is key for all AAC users who utilize eye gaze as their access method. To set up for eye gaze, allow the user to sit comfortably and in a relaxed position before positioning the device. Sometimes, people sit up straight to calibrate the device and then return to a different position after calibration is complete; this degrades performance because the person has moved significantly since the time of calibration. Again, please keep in mind: before positioning the device, make sure the user is in a relaxed and comfortable position

Device Positioning

• Angle:  The screen of the device needs to be parallel to the plane of the user’s face. If the user is sitting vertically, the device should be vertical. If the user is leaning back, the device should tilt forward to maintain a parallel orientation to the user’s face. A good point of reference, the user’s eyes should be parallel to the top of the device!

  

• Distance:  The WinSlate™ should be approximately 19.5-23.5 inches from the user.

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Troubleshooting Poor Eye Tracking

Poor Camera Focus

• The eyegaze camera will not be able to focus optimally on the user’s eyes if the WinSlate™ is not positioned correctly in front of the user (see above) or if the face plate of the tracker is dirty. 
• After making sure that faceplate is clean, reposition the device (move it closer or further from the end user) until consistent tracking regains. 
• To verify appropriate distance, use the distance indicator.  Instructions on this can be found in this article:  How do I calibrate eye gaze?

Common Challenges with Eye Glasses

If a user wears glasses and you are experiencing challenges with calibration, it is recommended that you use "Standard Camera Mode" or Zoomed Camera Mode" when calibrating.  This will allow you to more easily visualize what the camera is seeing.  More about that can be found in this article:  How do I calibrate eye gaze?

• Glare Reflections on Glasses:  Some users who wear glasses will have glare spots (bright reflection spots) on the lenses of their glasses.  To the eye gaze camera, these may look like pupils, which can ultimately confuse the camera. To correct this, either move the device to a different position/angle, or use "Sunlight Mode" and/or "Glasses Mode."  You can also tilt the eyeglasses by raising the earpiece off the ears slightly.  A slight repositioning of the tilt of the glasses often moves the reflective spots away from the pupil and alleviate the problem.
• Highly Reflective Glasses Frames:  Sometimes metal-framed or rhinestone/gem glasses that are highly reflective can cause calibration challenges. To the eye gaze camera, rhinestones or reflections may look like pupils, which can ultimately confuse the camera.  Solutions include using "Sunlight Mode" and/or "Glasses Mode," or opting for a simpler set of frames.
• Scratched or Smudged Lenses:  Scratches and smudges on the lenses of the glasses can distort the eye gaze camera's view of the pupils.  Ensure that you are using glasses with clean, clear lenses.

Occluded Pupils

• Eye tracking software relies on seeing the entire roundness of the pupil. If the user’s eyelids are drooping downward and covering the top part of the pupil, tracking quality will degrade. Users who demonstrate eyelid drooping benefit from mounting the device in a slightly higher position.

Medication

• The eye tracker looks for a pupil size within a certain range. If the user’s pupils are under- or oversized due to medication, you could experience intermittent tracking behaviors. 
• Those with dry eyes may have difficulty with eye tracking.

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False Clicking

• Sometimes you may notice the device selecting even if the user is not in front of it. The eye gaze camera is constantly searching for something that looks like a pupil, and sometimes, reflections from lights in the room, reflections off of the wheelchair, etc. can result in the eye gaze camera seeing a "false pupil."  This is the cause of the "false clicking" you may be experiencing.
• When eye gaze interaction is not in use, it is recommended that you do one of the following:
  • Select the "pause dwell" button.
  • Change the access method to "Mouse/touch."
  • Turn off the device completely (recommended to preserve battery).
  • Turn on "Glasses Mode" and/or "Sunlight Mode."  

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If you continue to run into challenges, you are more than welcome to reach out to our Forbes AAC Tech Support Team for additional assistance.  Options for contacting them can be found here:  Contact | Forbes AAC | Augmentative Communication