I have a UV lamp pointed at the wall and ceiling behind me, mostly for my parrot's sake. kinda blue-white visible light + UV. the light bounced off the wall and ceiling and a couple of reflective objects on my desk. now letters in a specific part of my field of vision become invisible. I can see how debilitating this would be when it's the sun bouncing off snow or sand.it didn't even hurt until I tried to read something.
I switched to a normal lamp. starting to be able to read ok now.