Brock string

The Brock string is the oldest tool in vision training. With it you learn to control how your eyes turn inwards and outwards, and you can train in all directions of gaze. You use it during a programme with your vision therapist.

What it trains

• Fixation from 0 to 3 metres – you learn to control your eyes’ movement inwards and outwards.
• Monocular training under binocular conditions – you use both eyes but “force” one of them to do the work.
• Anti-suppression – you become aware of whether both eyes contribute, or whether the brain suppresses the image from one of them.
• Timing and distance judgement – you learn to make your eyes hit exactly the same point at the same time.
• Binocular fusion – merging the images from the two eyes into one.
• Physiological diplopia – seeing the double string images outside the fixation point as a sign that both eyes are taking part.

Who it is for

For you if you want to improve your distance judgement and timing, for example in sport, and for you if you want both eyes to work well together.

How to use it

• Use the string according to your vision therapist’s recommendations.
• Hold the string up to the tip of your nose and spread the 6 beads along the string.
• Train looking straight ahead, to the sides and up/down – let your eyes “jump” or glide between the beads.
• Your eyes should hit exactly the point you think you are looking at – you can tell because the strings cross precisely there.
• With red/blue glasses you can see which string belongs to which eye.

Good to know

• White string, 3 metres long, with 6 beads.