on noticing someone looking at you

consider the “observer effect” with the double slit experiment.
observation requires visual focus of attent(ion) / intent(ion).
the eyes collect energy from what is observed.
perhaps, this energy can also be reflected out of the eyes.

laser
if eyes are focused,
the reflected energy exits the eyes in a narrow beam.
effects the double slit experiment.
causes someone to notice they are being looked at.

house light
if the eyes are not focused,
the reflected energy exits the eyes in a broad beam.

michael jackson:
“…always feel like somebody’s watching me”