For every 90 minutes of close-up vision or indoor screen time, one should spend 20-30 minutes outdoors engaging in non-close-up vision.

“At least every 90 minutes of looking at things up close, or even if you're looking at a screen, you know, television screen, or you're watching a movie, or you're indoors, for every 90 minutes of that, you ideally would have at least 20, probably more like 30 minutes of being outside, ideally. But if you can't be outside, of non up-close vision.”