FAQ: Can I disable auto-selection of a single eye after a binocular calibration?

[Sam]

For the head mounted EyeLink II, by default, after a binocular calibration, the Host software will automatically select the eye that had the better validation score and switch to monocular tracking for that eye. Please note, this behavior does not apply to more recent tracker models.

You can modify this behavior with one of the following methods:

• Manually re-select "Both" after calibration
  This is the simplest method to use on a trial-by-trial basis.
  • Perform your binocular calibration and validation as usual.
    
  • After the validation results are displayed, but before you click "Accept," look at the bottom of the Host PC screen.
    
  • Click the "Both" button (or press the 'B' key) to ensure both eyes remain selected for tracking.
    
  • Click "Accept" to begin recording.
    
• Permanently disable auto-selection
  If you always want to track both eyes and wish to disable the automatic selection feature entirely, you can do so by adding a command to the FINAL.INI file on the Host PC.
  • Access the FINAL.INI file*: This file is located in the /ELCL/EXE/ folder within the EyeLink partition.
    
  • Add the following line to the FINAL.INI file:
    
    Code:

    select_eye_after_validation = NO
  • Save the file.
    
  • Restart the Host software.
    
  Once this command is added, the system will no longer automatically select an eye, and whichever option was chosen before calibration (e.g., "Both") will remain active after validation is complete.
  
• Send the command in your experiment
  You can also send the select_eye_after_validation command temporarily from your experimental script. The syntax for this will vary based on your programming platform (Python, matlab, etc...).
  

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*The FINAL.INI file is in the /ELCL/EXE/ folder in the EyeLink partition on the Host PC. The FINAL.INI file can be edited via the file manager software (EyeLink 1000 Plus and EyeLink Portable Duo) or boot the Host PC to Windows (EyeLink II and EyeLink 1000) and edit the file there (the EyeLink partition shows up as another drive when booted to Windows).