Example : Quick-sighted as a cat.

Synonyms : hawk-eyed, keen-sighted, lynx-eyed, quick-sighted, sharp-eyed, sharp-sighted

Example : A policy of open-eyed awareness.
The vigilant eye of the town watch.
There was a watchful dignity in the room.
A watchful parent with a toddler in tow.

Synonyms : open-eyed, vigilant, wakeful