Vision therapy◷ 17 July 2026 · By Optom. Yeshwant Saoji
Do your eyes feel tired after screen time? Does your child squint, tilt their head, or complain of double vision? A simple tool called the Brock String can help — no batteries, no screens, just a string and beads.
What Is a Brock String?
The Brock String is a length of string with 3 colored beads, invented by Dr. Frederick Brock to treat binocular vision problems and convergence insufficiency. It trains both eyes to focus together on one point — improving eye coordination naturally.
Why Eye Coordination Matters
Your eyes need to work as a team. When they don’t align properly, you may see double, struggle to read, or feel constant eye fatigue. Brock String exercises retrain your eyes to converge and focus together.
How to Do the Brock String Exercise
- Get the tool – A 3-meter string with 3 beads (red, green, yellow). You can DIY one with buttons or beads.
- Set it up – Tie one end to a doorknob. Hold the other end against your nose.
- Place the beads – One near (6 inches), one middle (2–3 feet), one far (5 feet).
- Focus on each bead – Look at one bead at a time. You should see one bead and two strings forming a V (or X) meeting at it. Seeing two beads means your eyes aren’t converging properly.
- Shift focus – Move from near to middle to far bead, checking the “X” each time.
- Practice daily – 5–10 minutes a day is enough.
Best Time to Practice
Anytime works — morning, a lunch break, or before bed. Consistency matters more than timing.
Benefits of Brock String Exercises
- Reduces eye strain
- Improves reading focus
- Boosts sports performance (hand-eye coordination)
- Screen-free vision therapy
- Great for kids and adults alike
Final Word
The Brock String is a low-cost, effective way to train your eyes to work better together. If you or your child struggle with eye fatigue, double vision, or focusing issues, this simple string exercise might be all you need.
Consult an eye specialist before starting any vision therapy exercise.