Spending just 60 to 120 seconds focusing your gaze on a small window of your screen, it doesn’t only increase your visual acuity for that thing, but it also increase your attention.

As we get more tired, we blink more. You should practice not blinking as a way to increase your focus. Blinks actually reset our perception of time and space. The more you can do this, the more you can maintain a cone of mental focus.

How to focus to change your brain, Huberman Lab, 60mins.