florescent lights flicker. As a person with autism they can set me off in a heart beat if I am not ready. They can trigger anxiety, migraines and many other things. Some times different colors of sun glasses can help. When I worked in an office with those lights I had to bring in my own lamps to keep working. Oh, and old computer screens can do it too. I have a photograph somewhere that demonstrates the flicker with lights. If I can find it I will post it.