Pencil push-ups and the Brock string: how clinicians use them

What they are

Pencil push-ups and the Brock string are two home exercises that optometrists and orthoptists prescribe for convergence insufficiency. Both practise turning the eyes inward together. They are part of the wider set of eye exercises clinicians use, and should be done as your clinician instructs.

Pencil push-ups

A small target, such as a letter on a pencil, is held at arm's length. You focus on it and slowly bring it toward your nose, keeping it single. When it doubles, you move it back until it is single again. Your clinician sets the number of repetitions and how often.

In the CITT trial, home pencil push-ups alone were successful or improved in 43 percent of children, compared with 73 percent for office-based therapy with home practice. That is why clinicians often combine home exercises with supervised sessions.

The Brock string

A Brock string is a cord, often a few metres long, with several coloured beads. One end is held at the nose and the other is fixed or held away. As you look at each bead, you should see two strings that appear to cross at that bead. Where the strings cross tells you and your clinician where your eyes are pointing together.

It is used both as an exercise and as a way to check eye teaming during a program.

Doing them safely

• Follow the instructions, distances and repetitions your clinician gives you.
• Stop if you get eye pain, headache, dizziness or nausea, and mention it at your review.
• Some strain at first is common, but ask your clinician if symptoms worsen or persist.

Recording your sessions

Note the date, which exercise, repetitions, and how it felt. This helps your clinician adjust the plan. See the eye exercise log and the condition these exercises treat, convergence insufficiency.

Part of our guide to eye exercises: what the research says.