under the (watchful) eye of
Under the careful protection, care, or surveillance of (someone). They were supposed to be under the watchful eye of the teachers during the field trip, but two of the students managed to slip away undetected and went missing in the nearby woods. One had to be extremely careful what one said publicly back in those days, as we were all under the eye of the Soviet Union.
under the (watchful) eye of somebody
being watched carefully by somebody: The children played under the watchful eye of their father.