
Glass over
Emotional Indication
This expression suggests a lack of interest or emotion, not just physical tiredness.

During the movie, I saw his expression change and his eyes glass over.
Not Literal
'Glass over' is a metaphor; no actual glass is involved.

As the conversation drifted to economics, her eyes glassed over.
Momentary Change
The phrase often implies a temporary condition.

He quickly snapped back to attention after his eyes glassed over.
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