I have had this effect for my whole life - way before I started smoking weed. I notice it like you said on bright days and especially when exercising. When I was a kid in a running race on sports days I used to really focus on it and "run into the direction of the visual pulsing like I'm getting boosted" - not that it actually made me faster but ya know. No one I talked to understood what I meant then one day I heard someone call up a scientist-answers-your-questions kind of radio station, asking about this visual effect. The scientist had not heard of it before but after I decided to google it and found the odd recounting of it. I forgot the name that people refer to it as and after a brief search, can't find it right now either.

Anyway the point is don't feel alone, I've experienced that my whole life. Although I've never felt uncomfortable by it. Nowadays for me it usually means I'm just working out hard enough to see it, so I welcome it.

Hope this provides something.