spark in (one's) eye(s)
A sign of one's vitality, enthusiasm, determination, etc., as might be present or discernible in one's eyes. I could tell by the spark in his eye that he had another wild scheme in mind. Don't just settle for some humdrum job that will bore the life out of you. You need to find something that puts a spark in your eyes.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.