Canon EOS R3 Advanced User's Manual page 82

7.
Exit calibration.
Select [Exit]. Calibration results (calibration data) are saved to the
calibration number shown in step 2.
After calibration, look through the viewfinder and make sure the pointer
moves in response. If the pointer does not seem to follow your gaze
closely, perform calibration again.
Note
Also read General eye control precautions and Enhancing eye control accuracy.
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