Can you read the labels on the knobs and switches? Neither can I. Point being that you can never count on a particular light condition at a show.
Memorize the function and workflow of you instruments in near dark conditions where you can't read labels. This will prepare you for anything.
It's also a good idea to test you rig in bright sunlight. Better to find out you can't see anything at rehearsal than at a gig. Then come up with work arounds to remedy the situation.
Back in the day I gigged with an Ensoniq ESQ-1. I remember I was going to perform at an outdoor show. I couldn't see anything when I tested in bright sunlight. I built a little sun shield out of cardboard and black electrical tape.
Composer, Synthesist, Electronic Musician & Multimedia Artist | Sr. Systems Analyst | Founder of the Rocky Mountain Synthesizer Meetup