The American Academy of Optometry recently published a study on their findings from the CDC’s national survey of children’s health. What its members found was that children with vision problems were two times more likely to develop ADHD. Examples of these types of vision problems included disorders of eye alignment (more commonly known as crossed eyes) and eye movement (nystagmus), with researchers – led by Dawn K. DeCarlo, OD, MSPH, FAAO of the University of Alabama at Birmingham – analyzing data from the cross-sectional 2011-2012 National Survey of Children’s Health, itself conducted by the U.S. Centers for Disease Control and Prevention. Further, the sample included 75,171 children aged between four and 17, with telephone interviewers having asked about the child’s vision as assessed by a health care provider, ADHD, intellectual impairment and condition severity.

The results were eye-opening: Some 15.6-percent of children exhibiting vision problems had ADHD, while only 8.3-percent of children with normal vision exhibited the condition – equating to being 1.8 times more likely. For children exhibiting moderate vision issues, the rate shot up even higher – 2.6 times more likely. Following a multivariate analysis adjusting for confounding variables, it was found that vision problems were still independently associated with ADHD irrespective of patient and family characteristics. Dr. DeCarlo and other researchers were quoted as saying, “Children with vision problems should be monitored for signs and symptoms of ADHD so that this dual impairment of vision and attention can be best addressed.”

At the heart of this subject is Attention Deficit Hyperactivity Disorder, and how it’s a common neurodevelopmental malfunction, estimated to be present in eight to 11-percent of children in the U.S. While previous studies have in fact suggested connections between ADHD in children and vision impairment, these findings – in a rather large nationally representative sample – present new evidence that children with vision problems that cannot be corrected by use of glasses or contact lenses have a higher prevalence for ADHD…and that the association remains independent of differences in family and patient characteristics. And, as many entities in the fight to help kids with ADHD, it remains likely that a significant group of children exhibiting vision problems are incorrectly identified as having ADHD.


The Correlation Between ADHD and Vision Problems

As the study revealed more about this connection, it was found that difficulty seeing may indeed make it hard for children to finish schoolwork in a timely fashion or pay attention; additionally, the researchers suggest that vision problems may consume more of children’s “executive function” – that is, higher-order cognitive processes used to plan, organize, pay attention and manage time and space. Because ADHD is marked by inattentiveness, impulse behavior and hyperactivity, kids who suffer from it have trouble sitting, focusing and controlling their impulses – and the correlation between this and vision problems has been offered up in various forms by different experts in the field.

Some suggest that:

• Convergence insufficiency (a common near vision disorder) may be 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.

Dr. Maria Lymberis, Treasurer of the American Psychiatric Association, commented that “Hyperactivity is a very complex subject; all the ingredients have to be there if the brain is going to work properly. We can think of what the people conducting the vision correlation studies are doing as one piece of the puzzle.” Lymberis is also a proponent of the correlation between the two disorders, going on to add, “It’s not exactly a new idea – the brain is not one uniform thing, it represents many ‘centers’ with many different highly specialized functions. So, if one is having a problem even in a relatively minor part of the ‘circuitry,’ it can affect the overall attention performance.”


Drawing Conclusions About Kids with Vision Problems:

At the end of the day, experts point out that these findings suggest kids with vision problems should be monitored for signs and symptoms of ADHD so that, if present, this dual impairment of vision and attention can best be addressed. As the lead investigator on the University of Alabama at Birmingham study, DeCarlo believes that just because vision problems that aren’t correctable with glasses or contacts are associated with ADHD, it does not mean that one causes the other; furthermore, because it was produced in response to patients of DeCarlo exhibiting vision impairment and ADHD, the national study included a previous paper that reported an increased prevalence of ADHD among the children in her vision rehabilitation clinic.

“Because we do not know if the relationship is casual, we have no recommendations for prevention,” DeCarlo concluded. “As such, I believe it’s more important that parents realize children with vision problems may also have attention issues, and that both require professional diagnosis and treatment.” When asked if a child that exhibits vision malfunctions should worry parents about him or her developing ADHD, DeCarlo said, “I wouldn’t worry about them developing ADHD, but if they seemed to exhibit symptoms of ADHD, I would make sure that all of their vision needs are addressed through proper eye care and vision rehabilitation, and would have them evaluated by an expert in attention disorders.”

According to industry experts, Attention Deficit Hyperactivity Disorder remains one of the most frequently encountered neurodevelopmental conditions of childhood.