Types of Testing Techniques

Brock String

One of the very first techniques we teach is the Brock String. It is a very simple technique that gives the child incredible feedback and is often sent home with the child. The Brock String teaches awareness of eye aiming at various distances while checking for suppression (shutting an eye off). It can also be used for vergence facility training later along in the program.

Marsden Ball:

The Marsden Ball is used for eye tracking (fixation and pursuits) but can also be handy for eye-hand coordination. This activity will help develop understanding on how the eyes move, the ability to visually anticipate movement or change. Precise and predictable eye movements direct the purposeful movement of the body.

Plus/Minus Lenses:

The focusing system is telling the child what things are, identifying them. Sometimes a child does not have any control over their focusing system and doesn't recognize blur and know how to make things clear. We use Lenses to train focus (accommodation) and teach awareness and the appropriate visual response.

Red-Green Lenses & Filters:

Red-Green Lenses and Filters can be used to train a child out of suppression. Suppression happens when the brain shuts off information coming from an eye. This happens when the image is blurry, double or confusing in some way. It is a neurologically adaptive behavior and is a sign of an unstable visual system. Since vision therapy enhances binocular vision (two-eyed) both eyes must be turned on and working. These lenses help give the child feedback so they know when one eye shuts off as they can only see part of the target.


Vectograms are polarized slides used to train stereopsis (depth perception) and central and peripheral anti-suppression. They also allow for vergence training and teach a variety of skills like recognizing parallax and size differences. Vectograms are fun and provide a varied target that children find interesting. Prisms and balance boards can be added to further imbed the learned response so that the child can transfer what he/she is learning to other experiences.

Yoked Prisms:

Yoked Prisms are very fund to use in therapy and help turn on different visual pathways in the brain. This is one technique we use to "tickle the brain. We can use any eye-hand or eye-body activity with the prisms. Sometimes just standing up with yoked prisms on can be therapeutic.