Brock string

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A Brock string (named Frederick W. Brock) is an instrument used in vision therapy. It consists of a white string with a length of about 10 feet with three small wooden beads with different colors.

The Brock string is commonly used during the treatment of convergence mismatch and other anomalies of binocular vision. It is used to develop convergence skills as well as to interfere with one eye's emphasis.

During therapy, one end of the Brock rope is held at the tip of the nose while the other end is fixed to a fixed point. The three beads are spaced at various distances. The patient is asked to focus on one of the beads, while paying attention to the visual input of each eye and the sensation of convergence. Patients can use variable techniques to make it easier or more difficult by bringing beads closer to the nose and by using lenses and prisms.

Although this procedure is usually associated with binocular vision and anti-stress therapy, it can also be a valuable procedure for developing accurate fixation skills under binocular conditions.

Three (up to five) colored beads are placed on a rope length of at least 20 inches long. The patient is instructed to alternate the fixation and focus of one bead to the next bead while maintaining physiological diplopia awareness.

Purpose: To learn to see with both eyes simultaneously

Ingredients: Beads and String

Set up:

1. Tie one end of the rope to the doorknob. Position one bead at the end of the cable close to the doorknob. This is a distant fixation bead.
2. Place the middle fixation bead about 10 inches away from you.
3. Place a near fixture about 4 inches away from you.
4. Stand right in front of the knob facing it. Hold the rope up to the bridge of your nose so that the rope is stretched tightly between the nose and the door knob.

Procedure:

1. Look at the near fixing beads. Keep this bead when you see it live. If this near double bead indicates a problem of eye timing. if this happens, move the bead closer or farther until you see it as a single bead. The near bead should be moved closer and closer as the task becomes easier. Finally the near bead should be just an inch away from the bridge of your nose.
2. When you see the fixation bead near you should see two strings, each of which seems to come from your eyes. if your fixation of the bead is accurate, two strings should appear to meet exactly on the bead forming "X" (See illustration). When the bead is moved to an inch from your nose, the two strings should appear exactly on the bead forming a "V".
3. Slide the fixation to the middle fixation bead and then to the remote fixation and repeat. if your remote fixation is accurate, both strings must appear to meet exactly on the bead forming "V".
4. Change the location of the fixation beads and repeat again.
5. Try to realize other objects in your field from the View as you practice.
6. Gently turn your head from side to side through an angle of about 45 degrees maintaining your vision of two strings at any time. (if you rotate too far, one string will be lost.)

Video Brock string

References

• Scheiman, Mitchell and Wick, Bruce. Clinical Management Binocular Vision. Lippincott, New York. 1994. pgs 188-192. ISBNÃ, 0-7817-3275-1

Maps Brock string

External links

• Brock, YouTube
stringed training videos
• http://www.stereosue.com/wp-content/uploads/2011/04/The-Work-and-Wisdom-of-Dr.-Frederick-W.-Brock.pdf
• http://seeinstereo.files.wordpress.com/2013/10/brock-string-instructions.pdf
• http://seeinstereo.files.wordpress.com/2013/10/brock-string.pdf

Source of the article : Wikipedia