The 20-20-20 Rule for Eye Strain — Every 20 Minutes, Look 20 Feet Away for 20 Seconds

When you stare at a screen, your eye muscles lock into a fixed focal distance. Over hours, this creates strain, dryness, headaches, and that familiar end-of-day eye fatigue. The 20-20-20 rule is the simplest countermeasure ophthalmologists recommend: every 20 minutes, look at something at least 20 feet away for at least 20 seconds.

This gives your ciliary muscles a chance to relax and refocus. You do not need an app for this — just get in the habit of occasionally looking out a window or across the room. It will not fix serious eye problems, but it dramatically reduces the daily strain that screen work accumulates.