randomboolean Builds up for days if I let it and vision gets blurry, a takes a few days to return to normal. It's a gradual build up as opposed to fast without the protector. iPhone 8 Plus on iOS 12. Still not nearly as good as my PC set up by I'm resigned that a comfy and modern smartphone is some years away.
I'm happy personally but I don't want to give the impression this is particularly easy on the eyes and have someone buy the phone and regret it. It's hard to get even close to the comfort of my primary Win 7 + GTX 650 Ti + BenQ EW2440L setup, so everything falls short.