5% of school children show symptoms of convergence insufficiency (CI), headaches, dizziness and nausea, which can lead to irritability, low self-esteem, and the inability to concentrate. One study found that as many as 13% of children between the ages of 9 and 13 suffer from moderate to marked CI.
A study carried out by researchers at the Children’s Eye Center at the University of San Diego (2005), found that nearly 10% of patients diagnosed with CI also had a diagnosis of ADD or ADHD, and conversely, as many as 16% of children diagnosed with ADHD had CI (Note: Some ADHD drugs may aggravate CI, worsen accommodation and enhance blurred vision).
In the Diagnostic and Statistical Manual (4th ed.) used by psychiatrists/psychologists to diagnose a variety of mental health disorders, 5 of the 9 symptoms of ADHD overlap with CI.
A study carried out in England in 2009 found that children diagnosed with ADHD have a threefold increase in CI incidence as compared to controls, and a twofold increase in the incidence of tracking problems as compared to controls.
ISSUES TO CONSIDER
Doctors recommend that children get their eyes examined at ages 1, 3, and 5, especially since some eye problems may turn into permanent disabilities. (Disabilities, both physical and psychological: a study found that 85% of academically and behaviorally at-risk pupils in their sample failed one or more vision tests, primarily tracking and visual acuity).
Children often may not tell us they are having visual difficulties because they don't realise that they are seeing the world in a different way to everyone else (e.g. blurry vision).
An American study found that children log about 8,000 hours of TV and computer time prior to reaching school age.
Before labeling a child as having ADD/ADHD, evaluate them for developmental (e.g. visual/motor/auditory) problems first.
"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,” Dr. David B. Granet, Director of the Ratner Children's Eye Center in San Diego said.
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.