A New Focus for Eye Care

Nov. 26, 2001 -- See that picture on the wall? Now hold your index finger up in the line of vision and focus on the finger.

If you are lucky, you can hold a single image of your index finger in focus, while the picture on the wall in the background is liable to be double.

Now, try another simple exercise: Name the number that comes three before 97. If you said 94, that's because you were able to hold a visual image of a sequence of numbers in your mind and produce the correct answer.

These two exercises illustrate principles of "behavioral optometry," a field that offers not only an innovative form of vision care but also a unique approach to understanding the role of the eyes in thinking and learning.

'Retraining' the Eyes

Stephen Miller, OD, explains that behavioral optometrists are interested in how the eyes work together with the brain and the rest of the body to perceive images and help us navigate the world. It is an extension of the work of more traditional ophthalmologists and optometrists who specialize in how the eyes receive images, and who typically prescribe glasses, contact lenses, medicine, or surgery, he says.

Behavioral optometrists believe that some eye problems can be improved through techniques that "retrain" the eyes and the brain to work together better. Miller calls it a form of "occupational therapy for the eyes."

For instance, some people who have healthy eyes and relatively good vision may nevertheless find it hard to focus on nearby objects -- such as the index finger held up in the line of vision of the picture on the wall. Miller calls this problem "convergence insufficiency," which is the inability of the eyes to coordinate with each other to see an object.

To treat this problem, behavioral optometrists might have a person come to the office for weekly therapy, with "homework" assignments designed to reinforce what is learned in the optometrist's office.

"Depending on the problem and how significant it is, vision therapy could be done in as little as four to six weeks or as long as a year," says Miller, executive director of the College of Optometrists in Vision Development, in St. Louis, which certifies behavioral optometrists.

A typical homework assignment for a person with convergence insufficiency might be to hold a pencil at arm's length and focus on the tip, gradually moving it toward the nose. "At some point as you move it closer the image will break into two," Miller explains.

But through repetition, the person will gradually be able to hold a single image of the pencil tip all the way until it reaches the nose.

Problems like convergence insufficiency may be complicated by activities of modern living -- long hours of television viewing and staring at a computer terminal. And behavioral optometrists say many vision problems stem from the failure of our eyes to evolve beyond the more primitive functions for which they were designed, to meet the demands of our up-close visual world today.

"We have a vision system made for farmers and hunters being used in offices with no windows and no opportunities for focusing at distance," Miller says. "We are a near-centered society, but we have not evolved our vision system to adapt to that."