I was helping a welder fix a texas gate at one of my gas wells once (well, I was close by with a fire extinguisher in case of sparks)- I definitely didn't look at the welding, but I must have got some flash in my peripheral vision- the next day I had the sand im my eyes thing going on, and as I drove to work the sunlight was killing me. I had to park in the shade of my tank farm for a few minutes with my eyes closed before I could see again. Nasty.