According to a study, approximately 20% of 4.5 million children currently identified as having ADHD may have been misdiagnosed. Furthermore some researchers point to a major disparity between rates of ADHD in the US vs Europe to indicate that the US may potentially be misdiagnosing some cases of ADHD.

Many of the symptoms associated with ADD and ADHD can overlap with those associated with vision problems, and it is now well known that the two disorders can occur together. One of the common vision disorders that is often misdiagnosed as ADHD is convergence insufficiency, which makes it difficult for a child to do near work such as reading or writing. According to a meta analysis the rate of convergence insufficiency in school-age children documented in the scientific studies ranges from 2% to 13%, with the most common figure cited in these studies around 5%.

Why is ADHD often misdiagnosed?

In recent years, ADHD has been classified as part of the autism spectrum. The majority of these individuals will have a behavioural problem. In the early days, ADHD was primarily diagnosed through a questionnaire given to parents and teachers. Rather than using clinical tests to diagnose ADHD, a questionnaire was used, and patients were given stimulant trials to see if the treatment was effective, which is not exactly the best way to diagnose it.

In fact, it is possible and what is often neglected that ADHD is misdiagnosed when there is more of a visual processing deficit that can be easily addressed through vision therapy.

Why are undiagnosed vision problems sometimes misidentified as ADHD?

Imagine a child who has difficulty seeing things up close. They may have trouble sitting still while reading or doing school work. They may lack attention in the classroom since they anyway feel that they are “not smart enough”. These are just two simple examples that illustrate why a child with a vision disorder will oftentimes exhibit many of the same symptoms as ADHD. Because these vision conditions are so common (with some estimates showing that 15% or more of school aged children have a visual disturbance that impacts their ability to read), it is crucial for parents that suspect ADHD to have their child's vision tested by a developmental or behavioural optometrist.

Which vision condition is most commonly associated with ADHD?

Convergence insufficiency is the most common vision problem associated with ADHD. In convergence insufficiency, the eyes cannot focus together properly on close tasks, leading to symptoms such as blurry or double vision, slow reading, or eye irritation.

Recent research has found that children with ADHD have three times the risk of having convergence insufficiency.

It is unclear whether ADHD and convergence insufficiency have a direct connection, or if ADHD diagnoses are more common because convergence insufficiency is less well known, and therefore many children are mistakenly diagnosed with ADHD.