How to do it

  1. Hold up a thumb or a pen about 10 inches (25 cm) in front of your nose.
  2. When the dot grows, focus on your thumb until it looks sharp.
  3. When the dot shrinks, shift your focus to something at least 20 feet (6 m) away.
  4. Follow five slow cycles (about 40 seconds), ending on the far target.
  5. Without the guide: about 5 seconds near, 5 seconds far, 10 times.

Why it helps, and what the evidence says

Your eyes focus up close by contracting a small muscle inside the eye. Hours of screen work keep it working at one distance. Switching between near and far works that focusing system through its range and ends with it relaxed at distance.

The evidence for focus breaks is small and mixed, and focus exercises won't change your prescription. The American Academy of Ophthalmology says eye exercises are ineffective for nearsightedness, farsightedness and astigmatism.

Tips

  • Keep your glasses on if you normally wear them for distance.
  • Over 40 and your thumb won't get sharp? That's usually presbyopia, which is normal. Don't strain; just hold it a little farther away.
  • Breathe slowly while you shift. It's meant to be relaxing.

Read more: Eye exercises for computer users · The 20-20-20 rule.