How is this useful?

It helps you reduce eye fatigue, reduce the likelyhood of headaches, dry eyes or blurred vision if you spend way too much time in front of the screen.

What kind of eye exercises do you have?

We have half a dozen exercises that prompt you randomly, from taking a break to looking far out to observing a specific color around you. We would love to hear from you if you have more ideas

Are the notifications non-intrusive?

If you uncheck "Auto Notify", you'll only see a red eye in the Mac Menu bar with no intrusive notifications.

When exactly do you notify?

Only if you are active/working on your screen for the period of time you set. If you log out or when the display is off, the timer is reset.