The ADHD-vision connection

The ADHD-vision connection

When it comes to schoolwork, vision impairment and attention-deficit/hyperactivity disorder (ADHD) present barriers to success in the classroom.

"If a child can't see something, how on earth is he or she going to pay attention to it?"

According to new research, both are often present in the same children, too. Researchers—representing the University of Alabama at Birmingham's (UAB) School of Optometry, School of Medicine, and School of Public Health and the Alabama Institute for Deaf and Blind (AIDB)—found that children with vision impairment are more likely than peers to have parent-reported ADHD.

"This research really started with focus groups we did with parents and children with vision impairment through an NIH [National Institutes of Health] grant," says Dawn DeCarlo, O.D., M.S., first author and director of the UAB Center for Low Vision Rehabilitation. "When talking with parents, we found that the conversation often turned to ADHD."

What the research says
In the study—"Prevalence of attention-deficit/hyperactivity disorder among children with vision impairment," published in the February 2014 issue of the Journal of AAPOS—Dr. DeCarlo and colleagues examined the medical records and other information of 264 children ages 4 to 17 at UAB and AIDB.

"We found that one in five kids with vision impairment also had an ADHD diagnosis," Dr. DeCarlo notes.

They focused on four impairments: optic albinism, optic atrophy, retinopathy of prematurity, and optic nerve hypoplasia.

To be exact, 22.9 percent of children in the study with these vision impairments also had ADHD diagnoses. That is significantly higher than the state prevalence of 14.3 percent and national prevalence of 9.5 percent.

Interestingly, the higher prevalence related mostly to children with mild or moderate vision impairment. Children with total or near-total vision loss had an ADHD prevalence of 10.5 percent, similar to the general population.

"We excluded children with multiple disabilities, so this study looked at kids who were doing well other than their vision impairment," Dr. DeCarlo says.

Exploring the connection
The next research goal is to figure out the reasons behind it.

"The main hypothesis we're working under is that we all have a limited amount of executive function," she says, referring to how the human brain manages certain skills and tasks. "If we're using more of our executive function to cope with visual impairment, then we may have less of a reserve to deal with attention issues."

Dr. DeCarlo also allows for another possibility: Some symptoms of vision impairment may be identified as ADHD by mistake. In the past, other conditions, such as convergence insufficiency, have "masqueraded" as ADHD, for example.

She puts it even more directly: "If a child can't see something, how on earth is he or she going to pay attention to it?"

In either case, the current research comes with practical implications for ODs. "Basically, they should know that it is possible—and likely—that the prevalence of ADHD is higher in children with vision impairment," Dr. DeCarlo says. "As optometrists, we can help put their vision in perspective."

Read more on recent clinical research in the June AOA Focus.

July 11, 2014

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