Some eye conditions are more common in people with attention deficit hyperactivity disorder (ADHD). These include refractive errors, such as astigmatism, and convergence insufficiency, which makes it difficult for the eyes to remain aligned when looking at nearby objects.
However, visual impairments are not symptoms of ADHD. While there appears to be an association between some eye conditions and the disorder, scientists are not sure what the connection is.
In this article, we look at ADHD and the eyes in more detail, including the relationship with visual impairments, whether ADHD causes blurry vision, and what can help with these conditions.
What is ADHD?
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ADHD is a neurodevelopmental condition that affects attention and impulse control. It causes symptoms such as:
- hyperactive behavior, such as being unable to sit still
- impulsive behavior, such as taking unnecessary risks
- difficulty concentrating, especially for prolonged periods
- difficulty with organization, such as remembering to do homework or chores
ADHD can be predominantly inattentive, which means that it mainly affects a person’s ability to focus. It can also be predominantly hyperactive-impulsive, causing more of this behavior than any other symptoms. People with combined ADHD have a mixture of both.
Certain health conditions are more common in people with ADHD. Some examples of these include behavioral disorders, learning disabilities such as dyslexia, and anxiety or depression. A lesser-known coexisting condition is a visual impairment.
How does ADHD affect the eyes?
Visual disturbances are not part of the diagnostic criteria for ADHD. However, there is an association between conditions affecting eye health and ADHD.
A 2016 analysis of a survey of children with and without visual impairment found that ADHD diagnoses were more common in those with visual impairment. Out of 75,000 children, 15.6% of those with vision problems also had an ADHD diagnosis, compared to 8.3% of those without vision problems.
Research has shown links between the disorder and some specific visual impairments. These include:
- Astigmatic refractive error: Refractive errors occur when the shape of the eye prevents light from focusing correctly on the retina, making vision blurry. Astigmatism is a type of refractive error, and it is more common in children with ADHD.
- Convergence insufficiency: Convergence insufficiency means that the eyes lose alignment when a person tries to focus on a nearby object, causing blurry or double vision. A 2012 study found that children with ADHD had more convergence insufficiency symptoms than those without ADHD — and that convergence insufficiency was more likely to affect their performance when they had ADHD.
- Color perception: A small 2014 study found that young adults with ADHD were more likely to have difficulty perceiving colors in the blue range. However, as the study only included 60 people, the findings may not be generalizable.
Scientists are not sure why visual conditions and ADHD appear to be related, but there are some theories. The first relates to executive function.
Executive function refers to a person’s ability to plan, organize, and pay attention. People with ADHD sometimes have lower levels of executive function than people without the disorder.
However, the authors of the 2016 analysis suggest that those with visual impairments may experience this because they have to devote more of their attention to navigating the world, and so have a reduced ability to focus on other things. This may exacerbate ADHD symptoms or make them more obvious.
Another potential factor is misdiagnosis. Mild-to-moderate visual conditions are not always obvious in children, and young children may not be able to describe their visual impairments to adults. Difficulty seeing may result in children losing focus or taking a long time to complete tasks, which people may mistake for ADHD symptoms.
There is no evidence that eye health conditions play a role in causing ADHD.
Is being unable to unfocus the eyes on command an ADHD symptom?
No — not being able to unfocus the eyes on command is not an ADHD symptom. However, some eye conditions that affect the eye’s ability to focus are more common in people with ADHD. For example, convergence insufficiency makes it difficult for the eyes to focus on close objects.
This does not mean that convergence insufficiency is an ADHD symptom — only that there may be an association between the two conditions.
Another possible reason why some children with ADHD may be unable to unfocus their eyes on command is that they may become hyperactive or distracted during visual tests.
Can ADHD cause blurry vision?
Some eye conditions that cause blurry vision are more common in people with ADHD. This includes astigmatism and convergence insufficiency. However, this does not mean that ADHD itself causes blurry vision.
Researchers have not established a causal connection between ADHD and any eye symptoms. This means that, so far, there is no evidence that ADHD on its own can cause blurry vision.
What could help?
People with ADHD and eye conditions that affect vision may find that receiving treatment for their visual impairment helps with their ADHD symptoms.
A 2012 randomized controlled trial on convergence insufficiency in children with ADHD found that after treatment for their eyes, the children reported fewer eye-related symptoms and had better performance when reading.
Once a person has a clearer vision, they may find it easier to read, remain focused, and complete tasks. Some of the treatment options that could help include:
- Glasses or visual aids: It can help to ensure that adults and children with visual conditions have the correct glasses or contacts for their needs. Depending on the condition, other visual aids may help, such as magnifying tools or Braille.
- Base-in prism glasses: These force the eyes to work harder to converge. They can help a person with convergence insufficiency to read. However, they can be tiring for the eyes, so people typically only use them for short periods.
- Surgery: Some refractive errors and convergence problems respond well to laser eye surgery. A doctor can advise about whether this is a good option.
- Vision therapy: This is similar to physical therapy, in that it aims to retrain the eyes so that they move well together. Advocates say that it can help with eye movement, coordination, and focus. While the evidence is generally scarce, the results of a 2008 trial support its use.
People should not use eye patches to treat eye conditions such as convergence insufficiency.
As well as addressing visual difficulties, people can treat or manage ADHD symptoms through:
- family and parent training, which helps families learn how to respond to and support children with ADHD
- cognitive-behavioral programs, which can help individuals with ADHD learn and hone coping skills
- medications, which could include stimulant or non-stimulant drugs
School and workplace accommodations for ADHD can also make a significant difference. The American Academy of Pediatrics recognizes that the following can make it easier for children with ADHD to thrive at school:
- extra time to finish assignments
- less homework
- the ability to keep study materials with them in class
Could ADHD be a misdiagnosis?
The 2016 analysis states that in some cases, the outward symptoms of eye conditions in children may lead to a false diagnosis of ADHD. For this reason, it is important to seek an expert evaluation in order to diagnose ADHD, as this can rule out any other potential causes of these symptoms.
It is important to remember that while ADHD misdiagnoses can happen, it is possible to have both conditions. Parents, caregivers, and teachers should not attempt to diagnose either themselves.
For very young children, routine eye exams can help detect vision problems even before caregivers notice symptoms. The American Academy of Ophthalmology suggests the following schedule:
- a newborn eye exam
- a second screening between 6 and 12 months
- an eye screening between 12 and 36 months
- a vision and eye alignment check between 3 and 5 years
- a vision screening at 5 years to test for nearsightedness and other common issues
When to speak with a doctor
Consult a doctor if an adult or child is struggling to see, read, or remain focused.
Frequent headaches, eye strain, or difficulty completing work may be signs of an eye condition, particularly if these symptoms only occur when a person needs to focus on something nearby, such as when reading or doing written homework.
A doctor can run preliminary tests. If ADHD is a possibility, they can refer someone for an evaluation.
Follow up with an optometrist or ophthalmologist if:
- A child continues to have vision problems after ADHD treatment.
- A child’s vision gets worse.
- Vision treatment does not seem to be working.
Follow up with a doctor, psychiatrist, or therapist if:
- ADHD treatment does not help.
- Stimulant medications cause side effects.
- A child has new or worsening ADHD symptoms or those of another mental health condition, such as depression.
Summary
Some eye conditions are more common in people with ADHD, so the two may be connected in some way. At the moment, though, scientists are not sure where the link lies.
Difficulty seeing can cause or worsen problems with concentrating and completing tasks, so it is important to receive a professional visual evaluation and care. Treating both ADHD and eye-related symptoms can make it easier to focus and improve the quality of life.
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