Research on the Link Between Vision and ADHD

Granet DB, Gomi CF, Ventura R, Miller-Scholte A. The Relationship between Convergence Insufficiency and ADHD. Strabismus 2005 Dec; 13(4):163-8.

A new article, published by David Granet, MD, and his colleagues in the Ratner Children’s Eye Center, Department of Ophthalmology at UC San Diego, brings to the surface an issue that developmental optometrists have long been involved with.

First, some background information will be helpful. You probably already know what the letters “ADHD” represent: Attention Deficit Hyperactivity Disorder. You may not be as familiar with convergence insufficiency, which optometrists call by its acronym, “CI”. Convergence insufficiency, or CI, is a condition in which the patient has difficulty using both eyes together as a team in a near space, as occurs during reading or writing.

It might seem obvious that if a person has difficulty sustaining the use of both eyes together as a team for a period of time when reading, that reading would be stressful. In fact, the way many patients with this condition (CI) handle their difficulty is to frequently re-focus to a distance, look away, take breaks, or avoid the nearpoint task altogether.

For many years, that’s been obvious to us as developmental optometrists. In other words, a substantial number of patients who seek our care have a history of being able to attend very well when someone else is reading, but have a short attention span, or get antsy, when they have to read independently. They appear to have ADHD when in reality, they have visual inattention for a good reason.

The problem is that these patients are usually lumped together, and they end up in special education and are often medicated. While a small set of patients with true ADHD may benefit from medication, precious resources and money would be saved if those with visual problems such as CI were properly evaluated. Not to mention the anguish that many families experience when homework takes hours to accomplish because of visual inattention. Or adults who struggle to keep pace with jobs requiring sustained near performance.

This study, by Dr. Granet and colleagues at UCSD, is notable because it is the first paper published in a medical journal that establishes a direct link between ADHD and CI. In a review of 266 charts of patients with CI, these researchers found a three times greater amount had ADHD than would be expected among patients in general. While the authors are cautious about drawing conclusions from this, they emphasize that patients diagnosed with ADHD should be evaluated to determine if they have CI.

Studies of this nature should help call attention to children misidentified as having ADHD, when the underlying visual problem is left untreated. This is particularly important because CI is one of the more common visual problems that developmental optometrists help through vision therapy. In many instances, parents of children, and adult patients have reported to us that that their capacity to attend when reading, writing, or computing has improved substantially after completing vision therapy.