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FAQ: What are optimal values for the Pupil and Corneal Reflection thresholds?
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  • Pupil Threshold Adjustments
    For a properly thresholded pupil (fully colored blue with no blue appearing in the iris), the threshold value should be at least 75. Our Participant Setup video tutorials for each system and configuration discuss these adjustment details in more detail.

    If the pupil threshold value is below 75, the eye requires more illumination. You can increase the illumination level by adjusting the Illuminator Power setting on the "Camera Setup" screen or by moving the illuminator closer to the participant.

    Adjustments for the Long Range Mount
    If you are using the Long Range mount, you can also increase illumination by pulling the illuminator’s focusing lens outward (toward the participant) or by checking that the illuminator is aimed correctly at the participant's eye.

    For more details, see the guide: "How do I point / focus the illuminator on the Long Range mount?"

  • Corneal Reflection Threshold Adjustments
    After adjusting the illumination and pupil thresholds, check that the Corneal Reflection is properly thresholded (fully colored light-blue with no extra thresholding in the sclera). The exact CR threshold value is not critical, as long as it remains below 255.