12. The Phantom Finger

The Idea: Our eyes are taking in every image in front of them—only the brain is selective about what it sees. Part of the work of natural vison therapy is training the brain what to see (eyes + brain = vision). We can also train our brains to see things that aren't actually there, therefore expanding the brain's ability to see what is actually there. And there's nothing like a common party trick to get the job done.

How To:

Step 1: Bring your index fingers to eye level, about 20 cm in front of the face with tips pointed at each other, about 1 cm apart.

Step 2: Look at the space between your fingers. Do you see a third, double-ended finger floating between them? Look for it.

Step 3: Once you've got your Phantom Finger established, move it around—bring the fingers slowly up and down to the edges of your visual field, move them closer and further away, close the eyes and then open them—always maintaining the visual belief that the Phantom Finger is still there.

What's Going On:

The eyes see two fingers, but the brain puts their back ends together to make a third, sausage-shaped finger in the middle. This works the eye/brain connection of stereoscopic vision and is a useful exercise for anyone who has a "lazy" eye or sees things more clearly in one eye than in the other. Step 3 of the exercise—using movement and closing the eyes—helps strengthen both the breadth of the visual field as well as ability to focus at different near distances, while training the brain to see what we want it to see.

More info:

• Dr. Marc Grossman loves using these kinds of eye-brain tricks to help people see. He's collaborated with artists on some "Magic Eye" books, saying that they're good for the vision—the eyes and he brain working together.