Watching very closely, as in The buyers at the fashion show were all eyes. Worded slightly differently (with all one's eyes), this idiom dates from the mid-1500s. Also see its counterpart, all ears.
Words nearby all eyes
How to use all eyes in a sentence
But along with the cartoon funk is an all-too-real story of police brutality embodied by a horde of evil Pigs.‘Black Dynamite’ Presents Police Brutality: The Musical|Stereo Williams|January 9, 2015|DAILY BEAST
In that photo, Merabet has a big smile that spreads across his whole face and lights up his eyes.
She jumps on his back, mock-choking him and covering his eyes.Sia and Shia LaBeouf’s Pedophilia Nontroversy Over ‘Elastic Heart’|Marlow Stern|January 9, 2015|DAILY BEAST
The benefits of incumbency are quite potent, especially in the all-important area of raising campaign funds.
She narrowed her eyes, bit her lip as if to chew over the question, and whisked some stray blond hairs away from her face.Powerful Congressman Writes About ‘Fleshy Breasts’|Asawin Suebsaeng|January 7, 2015|DAILY BEAST
Bernard stood there face to face with Mrs. Vivian, whose eyes seemed to plead with him more than ever.Confidence|Henry James
Joe looked at her with a smile, his face still solemn and serious for all its youth and the fires of new-lit hope behind his eyes.The Bondboy|George W. (George Washington) Ogden
He turned his eyes upon her; but no sympathy was in their beams; no belief in the semblance of her tears.The Pastor's Fire-side Vol. 3 of 4|Jane Porter
The aged woman made no reply; her eyes still studied Ramona's face, and she still held her hand.Ramona|Helen Hunt Jackson
A flash of surprise and pleasure lit the fine eyes of the haughty beauty perched up there on the palace wall.The Red Year|Louis Tracy