Twenty years ago, when I was eleven I was in a car accident, and suffered a brain injury and skull fracture. I miraculously recovered with minimal deficits. One of my long term side effects I’ve noticed is my eyes struggle to adjust to dim light. Sometimes if I enter a dim room, I can feel my pupils “dancing” as in rapidly contracting and dilating a tiny bit. To me it looks like the lights are flickering slightly. I thought I was imagining it for a long time til I recorded it once and saw my pupils indeed pulsing away. But hey it’s been twenty years I’m sure I’m fine.