The Importance of Brock String Exercises

Young girl testing vision using Brock string

How Brock String Exercise Can Help Improve Your Eyesight

Acuity, the ability to see clearly, isn't the only factor in good vision. Your child's usable vision may suffer if their eyes don't work well together as a team when they focus on near objects. Fortunately, a simple string exercise can help them improve blurred or double vision and reduce eyestrain as well as other symptoms.

Difficulty Focusing Can Cause A Variety of Vision Symptoms

Brock strings may not be high-tech, but they offer an effective, time-tested way to refine your child's vision. Named after Swiss optometrist Dr. Frederick Brock, the device consists of three brightly colored beads strung on a 10-foot-long string. One end of the string is attached to a stationary object, while the user holds the other end.

String exercises are often used to address convergence insufficiency, a condition that occurs due to a misalignment of your child's eyes. As you view a close object, both of their eyes must turn inward slightly to create a single clear image of the object. If one eye drifts outward, they may experience:

  • Blurred or Double Vision
  • Sore Eyes
  • Fatigue When Reading, Sewing or Performing Other Close Work
  • Headaches
  • Difficulty Concentrating
  • Slow Reading Speed
  • Trouble Keeping Their Place When They Read
  • Words That Seem to Jump on the Page
  • Difficulty Catching or Hitting a Ball When Playing Sports

Strabismus, or crossed eyes, is a common cause of convergence insufficiency. Convergence insufficiency can occur even if your child's eyes aren't noticeably misaligned. Alignment issues can be subtle and may only appear when they attempt to look at a close object.

In some cases, the misalignment may cause your child's brain to suppress the information that it receives from one of their eyes. The condition, called amblyopia, can cause blurry or double vision and problems with depth perception or coordination.

Convergence insufficiency can also become a problem for adults if you have Parkinson's disease or have had a stroke.

You may have heard that eye alignment issues can only be corrected during childhood. Although eye doctors once believed that the brain lost the ability to change and adapt during adulthood, we now know that this simply isn't true. In fact, vision therapists have successfully treated convergence insufficiency and amblyopia in both children and adults.

Brock String Exercises Gradually Improve Close Vision

If you've suffered from double vision, difficulty reading, or poor depth perception all of your life, Brock string exercises and other vision therapy exercises and activities may improve your usable vision and your comfort.

One Brock string exercise involves moving the first bead four or five inches from your face, the second bead a few feet away, and the third bead at the end of the string. As you perform the exercise, you'll hold the string against your nose, keeping it taut.

You may have a problem with convergence insufficiency if you see two beads instead of one when you look at the closest bead. If that's the case, move the bead farther away until you only see one bead. As you slowly move the bead closer to your face, try to keep it in focus as it gets closer to your eyes. Performing this exercise regularly will encourage your eyes to work together when you focus on near objects and may even improve suppression issues.

This is just one of several Brock string exercises that your vision therapist may recommend if you or your child have convergence insufficiency, strabismus, amblyopia, or another condition. The exercises not only make reading and other close work easier but may also improve sports performance.

Could you or your child's vision issues be improved with vision therapy? During a comprehensive eye examination, a vision therapist conducts an array of tests that help him or her diagnose convergence insufficiency and other issues that may affect your or your child's vision.


National Eye Institute: Convergence Insufficiency

Healthline: 3 Eye Exercises to Help Strabismus

Medical News Today: 3 Eye Exercises to Help Strabismus


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