To shine with intermittent gleams
To emit light suddenly in rays or sparks
To open and close the eyes rapidly
A sudden quick light
A very brief time
Comprehension put a twinkle in his eyes.
The smile started as a twinkle in his eyes and spread to his lips.
His eyes began to twinkle again.
His brows shot up and a twinkle came into his eyes.
He smiled, a twinkle coming into his eyes.