Resolved questions
What's the meaning of "bright" here?

Murph and I leaned against each other until the weight of our bodies found their balance. Sterling inched closer to the lieutenant and fixed his eyes in a hard glare that traversed the rest of us on the roof. I looked at the lieutenant as he spoke. His eyes were dim. Before he continued he let out a short, bright sigh and rubbed a rash the color of washed-out raspberries with two fingers.
What's the meaning of "bright" in the last sentence?
Thanks!