Hi Val, We have a constant problem in the bright middle east sun. Some customers have given sun glasses to users. It helps. There used to be a Israeli company that made glasses specifically for this purpose, I dont recall the name though. Such glasses are also used in outdoor sports. I see cricket players using them particularly during the night games where they need to look up to catch the ball which could be directly in line with the flood lights of the stadium. I think a google search might help you find them. 

Good idea, thanks, Tariq!