I picked up one of these today. It's an led flashlight that fits in the palm of your hand with a variable control ring that lets you vary the light output from a fraction of a lumen to a blinding 190 lumens.
https://www.ledtorchshop.com.au/prod...190-ansi-lumen
At the minimum setting it emits just enough light to read your watch. I doubt it would affect night vision as long as you didn't stare into the led itself. Very smooth linear light control. Not cheap though.