accommodation, activity, spatial computation, Vergence, visualization

Brock String – Saccades

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The Brock String is the basis for some wonderful activities, helpful in developing visual skills. Brock Strings are used to

  1. Create awareness of space and depth.
  2. Increase the range of motion of the eyes.
  3. Increase accuracy and range of targeting.
  4. Improve scanning ability.

Brock String – Saccades is not a traditional Brock String activity in that there is no inward/outward movement of the eyes to track targets. Instead, the string is held out across the client’s field of view and the client scans across, left to right, from one bead to another, then starts over again.

‘Saccades’ is pronounced either ‘sack-aids’ or from the French pronunciation ‘sack-ahds’. It means ‘jump’ eye movements, and in this case refers to the sort of short hops and quick fixations that occur when reading. To proceed:

  1. Take a 40-50 cm length of string and space all beads evenly across this length of string.
  2. The string is to be held out horizontally across the client’s field of view so that the beads are lined up left to right at about the nose level initially. The spread of the beads should not exceed an angle of about 30 degrees with respect to the nose. So, if the beads are closer together, the string can be closer to the nose. If the beads are more separated, the string should be held further away. Remember, the ‘spread’ of the beads should be representative of a page of text held at a comfortable reading distance. Start with this: Spread the beads across 40 cm of string, and hold it out at about 50cm from the client’s nose.
  3. Instruct the client to move the eyes from one bead to another in sequence left to right. Do this slowly at first, holding fixation on each bead for perhaps one second so you can verify that both eyes are on target.
  4. Increase the speed of tracking left-to-right, always returning to the first bead on the left.
  5. Repeat the tracking 9 times left-to-right, then repeat 3 times right-to-left. Repeat this cycle a few times.
  6. Try also to change the height of the string so that it is above the client’s nose level and then below.
  7. Consider using a metronome to re-enforce accurate tracking: Each click of the metronome for each hop. Start at 60-70 beats per minute and if that is easy for the client, gradually boost the speed to 80-180 beats per minute.

See Also:

You should study all notes relating to Brock String activities prior to attempting them. Always follow the guidance of your vision care provider. Do not exceed what clients can comfortably tolerate.