Some kids who are diagnosed with ADHD or autism

don't have it -- they are just seeing double ("convergence insufficiency"), according to an article in the New York Times.

Experts estimate that 5 percent of school-age children have convergence insufficiency. They can suffer headaches, dizziness and nausea, which can lead to irritability, low self-esteem and inability to concentrate.

Doctors and teachers often attribute the behavior to attention disorders or seek other medical explanations. Mrs. Gragg said her pediatrician had never heard of convergence insufficiency.

Dr. David Granet, a professor of ophthalmology and pediatrics at the University of California, San Diego, said: “Everyone is familiar with A.D.H.D. and A.D.D., but not with eye problems, especially not with convergence insufficiency. But we don’t want to send kids for remedial reading and education efforts if they have an eye problem. This should be part of the protocol for eye doctors.”