Dr. David B. Granet, director of the Ratner Children's Eye Center in San Diego, says workers at the center began noticing that many patients being treated for convergence insufficiency -- an inability to focus the eyes at close range -- were also being treated for ADHD.

ADHD is marked by inattentiveness, impulsive behavior and hyperactivity. This means that kids who have it have trouble sitting, focusing and controlling their impulses.

By reviewing the charts of 266 patients, doctors at the center found that nearly 16 percent of the people with ADHD had convergence insufficiency problems. That's more than three times as many as would be statistically expected.

"It just seemed over and over this was coming up. That's how a lot of research begins. Your clinical impression comes first and that leads you down a pathway," Granet says.

But this pathway may be more of a rocky road, adds Granet, who cautions against jumping to any conclusions.

"I think we've got something in convergence insufficiency that makes the symptoms of ADHD worse, and by treating it, we may be able to help those kids with ADHD cope and function," he said.

But he warns that there are many possible explanations for the relationship:

• Convergence insufficiency may be being misdiagnosed as ADHD, skewing the numbers.
  
  

• ADHD may be causing the convergence insufficiency.
  
  

• The same problem in the brain that causes ADHD may also cause convergence insufficiency.
  
  

• The drugs that children take for ADHD may be causing convergence insufficiency.

The size of the group and the fact that they all were all eye patients may present a statistical aberration.

"We just don't know yet how this association works," Granet says.

Dr. Maria Lymberis, treasurer of the American Psychiatric Association, echoes those sentiments.

"Hyperactivity is a very complex subject. All the ingredients have to be there if the brain is going to work properly. So you can think about what the people at the eye center are doing as one piece of the puzzle," she says.

Lymberis would not be surprised if a relationship between the two disorders is eventually proven to exist.

"It's not exactly a new idea. The brain is not one uniform thing. It is many centers with many different highly specialized functions. So if you're having a problem even in a relatively minor part of the circuitry, it can affect your overall attention performance," she says.

"The next step is to roll up our sleeves and do more work," says Granet. The Ratner Center next will look at children before and after they take ADHD drugs to see if the drugs were part of the equation, he says.

"I'd bet that most psychiatrists and pediatricians are not that familiar with convergence insufficiency and maybe the best thing that comes out of this is that those experts dealing with ADHD will be more aware of this."

What To Do

Conversion insufficiency affects 3 percent to 5 percent of the population. It can usually be treated with special eye exercises. If your child seems to have difficulty focusing when reading, see an eye-care specialist.

A previous HealthSCOUT story says drugs and counseling are the best treatment for ADHD.

"3D Vision" presents a checklist to see if your child may need to see a specialist. And here's an extensive site on attention deficit disorders.

For additional information on ADD/ADHD and Vision, see www.add-adhd.org