ADHD Diagnosis in Kids

Is It ADHD or a Vision Problem?

If your child is fidgety, hyperactive, or distressed by his schoolwork, an ADHD diagnosis might seem like a no-brainer. But these behaviors may actually be due to vision problems instead. Learn how to tell the difference — and how to get an accurate diagnosis.

Glasses held in front of a chart used to test for vision problems, which often co-occur with ADHD
Glasses held in front of vision chart, black letters on white background

Vision disorders sometimes mimic symptoms of attention deficit disorder (ADHD or ADD). In some cases, children are incorrectly diagnosed with ADHD, and started on medication, even though vision problems, like convergence insufficiency, are the root of the trouble. A recent study found that children with vision problems were two times more likely to develop ADHD than their peers, and that school nurses do not attribute poor attention and behavior to vision problems in the classroom.

The study1 suggested that, like ADHD, problems with vision make it hard for children to finish schoolwork in a timely fashion or to pay attention. Some researchers think that vision problems affect children’s “executive function” — the higher-order cognitive processes used to plan, pay attention, and organize time and space.

When we read, our eyes converge to focus at the same point on the page. If our eyes are not working properly, we lose focus and forget material we just read. Words seem blurry. Due to eyestrain from vision problems, children dislike reading. They become agitated or fidget when asked to read. Many act out in the classroom or during homework time. Their frustration can actually lead to anxiety and mood disorders.

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Most schools and pediatricians do visual screening. The children read letters or symbols on a Snellen chart. If a deficit is detected, prescription eyeglasses are usually ordered. However, functional vision depends on more than visual acuity. Our eyes have to work together to fixate on a stationary object, track a moving object, or scan to find an object in the environment.

When Reading Becomes Unbearable

Children who have vision problems usually avoid reading or develop negative behaviors to escape the task. The extra effort needed to focus and process visual information may cause fatigue and headaches. It is easier to look away from their papers or just to daydream.

Taking notes in the classroom involves switching eye focus from the board to the paper, and this is hard for children with functional vision deficits. There may be only a brief time in which they can complete their work before fatigue sets in. They rush through assignments to avoid blurry or double vision, headaches, and eye fatigue. They make careless mistakes due to poor attention to detail.

Convergence insufficiency has been well studied. One study suggests “an apparent threefold greater incidence of ADHD among patients with CI, when compared with the incidence of ADHD in the general U.S. population,” according to David B. Granet, M.D., of the University of California at San Diego. “We also note a seeming threefold greater incidence of CI in the ADHD population. This may represent an association and not be a causative relationship. Until further studies are performed, however, patients diagnosed with ADHD should be evaluated to identify the small subset that may have CI — a condition that responds well to treatment.”

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Clearing Up the Problem

What should you do if you suspect your child has ADHD? Experts recommend that he be evaluated for functional vision problems by a certified optometrist, and also be evaluated for ADHD. If convergence insufficiency is diagnosed, vision therapy is usually recommended. The therapy helps a child’s eyes work together by teaching the eyes to move properly without fatigue. It is typically done by a developmental optometrist (OD) or a vision therapist, who works under an OD’s supervision.

Vision therapy requires multiple sessions. Exercises include movement activities that challenge vision, such as catching a ball while jumping on a trampoline, or bunting a ball hanging from the ceiling on a rope. School accommodations for vision problems include highlighting every other line of text with different colors, and using special fonts to help strengthen eye movement skills. Some parents ask the school to allow a child to copy material from a paper on his or her desk instead of copying from the board.

Parents can help improve their child’s visual perception: Print out worksheets on different-colored paper. Sometimes bright white paper is taxing for tired eyes. Ask your child which color paper is easiest for her to see. Or draw part of a shape or item and ask your child to draw the rest. This is called “visual shape constancy,” and it trains the eyes to focus better.

Is it ADHD or a vision problem? The issue isn’t black and white. Through a functional vision test, doctors can determine if any of a child’s challenges are due to poor vision.

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“It’s important for parents to realize that children with vision problems may also have attention issues,” says Dawn DeCarlo, O.D., associate professor of ophthalmology at the University of Alabama. “Both conditions require diagnosis and treatment.”

The Eyes Have It?

Here are some signs of functional vision problems, many of which are similar to symptoms found with ADHD:

  • Struggles with reading and/or writing despite being bright
  • Covers one eye when reading
  • Develops disruptive classroom behaviors or cannot sit still
  • Tests poorly, despite knowing the material
  • Takes a lot of time to complete homework and assignments
  • Has a short attention span
  • Talks during instructions and distracts other students
  • Loses her place while reading, sees double, skips lines or words
  • Careless when working, making frequent mistakes
  • Performs strongly in the beginning of the assignment, but can’t make it to the end because of fatigue and anxiety.

1 Decarlo, Dawn K., et al. “ADHD and Vision Problems in the National Survey of Children’s Health.” Optometry and Vision Science, vol. 93, no. 5, 2016, pp. 459–465., doi:10.1097/opx.0000000000000823.