"She touched faces and would bring everything to mouth. She would go up to people, sniff them and touch their cheeks.”

Nine-year-old Raea Gragg would exhibit odd behaviors in her earliest years. She refused to make eye contact, and would smell objects indiscriminately. She was checked for a variety of illnesses, from the autism spectrum to anxiety disorder. She was even given anti-depressants.

What was her true diagnosis?

Though she had already had two eye exams, finding her vision was 20/20, this year a school reading specialist suggested another. And this time the ophthalmologist did what no one else had: he put his finger on Raea’s nose and moved it in and out. Her eyes jumped all over the place.

Within minutes he had the diagnosis: convergence insufficiency, in which the patient sees double because the eyes cannot work together at close range.

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.”