An EyeLink 1000 Plus Tutorial: Running an Experiment
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2013-2017 SR Research Ltd.
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participant is looking at the screen and not blinking, there is a problem with
the setup that must be addressed to prevent data loss.
Indicates Status of Pupil
OK = Pupil is visible
SIZE = Pupil is too large or too small
MISSING = Pupil is missing
BOUND = Pupil is missing or the gaze
data is not valid
The pupil status error message “SIZE”, highlighted in yellow, indicates that the
size of the pupil is too large or too small. For the Remote Mode, the pupil “SIZE”
warning typically suggests that the pupil size is too small because of the
ambient lighting or the eye tracker is placed too far away from the participant.
The pupil status error message “MISSING” highlighted in red, indicates that the
pupil is missing from the camera view. This could be that the participant is
blinking. It could also be that there is a problem with camera setup. Please
adjust as needed.
Indicates Status of Corneal
OK = Corneal is visible
MISSING = Corneal is missing
BOUND = Corneal is missing or the
gaze data is not valid
The corneal status error message “MISSING”, highlighted in red, indicates that
the corneal reflection is not visible to the camera. See section 3.4 for details on
how to set up corneal reflection properly.
All status flags remain on for a minimum of 200 milliseconds, even if the
condition that caused the warning or error to be raised lasts for less than 200
milliseconds.
3.8 Validation
It is important that any problems with the calibration be identified and
corrected before eye-movement recordings containing inaccurate and poor
quality data are collected. By running a validation immediately after each
calibration, the accuracy of the system in predicting gaze position from pupil
position can be established. If performance is poor, the calibration/validation
cycle should be repeated before data collection begins.
During validation, targets are again presented to the participant in a random
order, similar to the calibration procedure. When the participant fixates these,
