Attention deficit hyperactivity disorder (ADHD) is more prevalent in children with uncorrected mild and moderate visual issues than their normal-sighted peers, new research has concluded.
Researchers at the University of Alabama at Birmingham, in the US, found the correlation in data from the 2011-12 National Survey of Children’s Health, which looked at more than 75,000 US children without intellectual disabilities.
The survey asked parents if a doctor or healthcare professional had ever diagnosed their child with a chronic condition, including ADHD, intellectual impairments or visual problems that could not be corrected with spectacles or contact lenses.
Study co-author and Centre for Low Vision Rehabilitation director, Dr Dawn DeCarlo, told OT: “These types of vision problems could be anything from colour vision deficiency to amblyopia, but would also include children like those seen in my clinic with vision impairment.”
The US Centres for Disease Control and Prevention survey also collected information about the severity of these conditions.
The university team found a significantly greater prevalence of ADHD in children with moderate, as well as mild, vision problems, when compared to children with no history of visual difficulties.
The association between the conditions remained even after adjusting for other factors that are known to be linked to ADHD, Dr DeCarlo said.
“More work needs to be done to understand why there is an association,” she explained.
“It could be as simple as children with vision impairment being mislabelled as ADHD because they are not able to pay attention to things they cannot see. Or, it could be much more complex, including the possibility that they are using so much of their executive functioning ability to compensate for their vision impairment that they do not have an adequate reserve of executive functioning capacity to maintain or change attentional states.”
The odds that a child with severe vision problems would also have ADHD was not found to be significantly different from those of normal children, but the small number in the former group might have played a role, the team concluded.
University of Ulster optometry lecturer, Dr Julie McClelland, told OT that the results should be of interest to optometrists and GPs, as well as parents.
She said optometrists, though not trained to diagnose ADHD, might want to bear the link between the condition and vision in mind and report any concerns to the child’s parents and GP.
Dr McClelland noted: “A lot of people work in isolation. It’s essential that people think about these children holistically.”
She said a follow-up study using paediatricians and eye care professionals to confirm the children’s conditions would add to these “significant findings.”
Dr DeCarlo and her fellow researchers have previously published a paper on the link between vision problems and ADHD based on young patients from Alabama clinics.
The research follows a University of California, San Diego, study in 2005 showing a relationship between convergent insufficiency and ADHD diagnosis.