BVD in School-Aged Children: A Guide for Parents

Every school year we meet children who are bright, curious and genuinely trying, and who still dread reading. They lose their place, rub their eyes, get a headache by mid-afternoon, or hand in half a worksheet. Sometimes the explanation is not effort or attention at all. It is that the two eyes are not working together comfortably at near.

Clinicians group those problems under the umbrella term binocular vision dysfunction, or BVD. Our complete guide to binocular vision dysfunction covers the whole picture; this article is written for the people who see a school-aged child every day, at the kitchen table and in the classroom.

Key takeaways

• BVD is an umbrella for several measurable eye-teaming and focusing problems, not one diagnosis. There is no dependable prevalence figure for the umbrella, so we do not quote one.
• Its best-studied member is convergence insufficiency: about 13% of fifth- and sixth-graders in a school-based US study met a high-suspect or definite definition (Rouse et al., 1999).
• The symptoms overlap with inattention, and children with convergence insufficiency report more school-behavior problems even when nobody has mentioned ADHD (Rouse et al., 2009).
• Office-based vision therapy has strong placebo-controlled evidence for symptomatic convergence insufficiency in children (CITT, 2008) and, in the larger CITT-ART trial, no symptom advantage over placebo (CITT-ART, 2019) and no proven benefit for reading scores (CITT-ART, 2019). Both facts belong in the same conversation.
• Classroom accommodations reduce the visual load. They are supports, not treatment, and only an examination can say what is actually going on.

What binocular vision dysfunction means

Each eye sends the brain a slightly different image, and the brain fuses the two into one. That fusion is what makes print sit still and look single. Most children have a small resting misalignment the system corrects automatically. Trouble starts when holding the two images together at reading distance costs more effort than the system can comfortably supply.

Under the BVD umbrella sit several conditions an examination can actually measure: convergence insufficiency (the eyes struggle to turn in and hold a near target), accommodative insufficiency or infacility (focusing is weak or slow to shift), vertical heterophoria (a small up-and-down misalignment), and ocular motor dysfunction (inaccurate tracking across a line of print). They travel together often. In the CITT trial, 74% of children with symptomatic convergence insufficiency also had an accommodative problem (Scheiman et al., 2011).

BVD is also not the same as needing glasses: a child can read the 20/20 line on the wall chart and still be miserable eight inches from a book.

Signs parents and teachers notice

Children rarely say “my eyes will not team.” They say homework is boring, or say nothing at all, because the way they see is the only way they have ever seen. What adults notice instead:

• Eye rubbing, squinting, or one eye closing or covering during near work
• Headaches, especially late in the school day or after reading
• Losing place, skipping lines, using a finger long after peers stopped
• Words that blur, swim, or briefly go double
• Avoiding reading, homework or fine detail, or fatiguing quickly at it
• Clumsy handwriting spacing, poor copying from the board, motion sickness or dizziness in busy rooms

Researchers score these with the Convergence Insufficiency Symptom Survey, which separated children with CI (mean 30.8) from children with normal binocular vision (mean 8.4) at a cut-off of 16 (Borsting et al., 2003). It is a validated research measure, not a home diagnostic test. If the list sounds like your child, that is a reason to be examined, not a conclusion.

Why it gets mistaken for an attention problem

From the front of a classroom, a child who cannot hold a near target comfortably and a child who will not stay on task can look like the same child. Three separate studies show how often the two turn up together. A pediatric ophthalmology practice reviewed 266 charts of patients with convergence insufficiency and found that 26 of them, 9.8%, had been diagnosed with ADHD at some point in their care; running the search the other way put CI at 15.9% of the ADHD records (Granet et al., 2005). A national survey of 75,171 children aged 4 to 17 found current ADHD reported for 15.6% of the children whose parents described a vision problem that glasses or contacts could not correct, against 8.3% of children with normal vision, an association that held at an odds ratio of 1.8 after adjusting for other factors (DeCarlo et al., 2016). And when CITT researchers asked parents about schoolwork behaviors, the children who had symptomatic CI but no reported ADHD still scored higher than children with normal binocular vision, 11.7 against 8.7 on a 24-point scale (Rouse et al., 2009).

None of that shows vision causes ADHD; it shows the two travel together. Vision therapy is not a treatment for ADHD, and a vision evaluation does not stand in for a developmental or psychological one. What the overlap does argue for is measuring how the eyes work at near before “won’t pay attention” is accepted as the whole story, which we walk through in vision problems versus ADHD.

What the treatment evidence shows, and what it does not

For symptomatic convergence insufficiency in children, the evidence is unusually good. In the 221-child CITT, 73% were successful or improved after 12 weeks of office-based vergence and accommodative therapy with home reinforcement, versus 35% on office placebo (CITT, 2008). Of those who became asymptomatic, 84.4% of the office-therapy group still were a year later (CITT, 2009), and a Cochrane review of 12 trials, six of them in children, reached the same conclusion (Scheiman et al., 2020).

The later, larger CITT-ART trial complicates that picture, and parents deserve it in full. Clinical signs improved much more with therapy than placebo, but symptom scores improved about equally in both groups (CITT-ART, 2019), and reading comprehension improved 3.7 points with therapy versus 3.8 with placebo: no reading benefit at all (CITT-ART, 2019).

The wider reading question is genuinely contested. The AAP, AAO, AAPOS and AACO joint statement holds that dyslexia is language-based and that vision therapy is not supported for learning disabilities (AAP et al., 2009), and a 5,822-child cohort found four of five severely impaired readers had normal ophthalmic function (Creavin et al., 2015). The optometric bodies read the same landscape differently, holding that vision problems can and often do interfere with learning and that optometric care is one part of a multidisciplinary approach (AAO/AOA, 1997). Our position, offered as clinical perspective rather than trial evidence: vision problems do not cause dyslexia and we do not treat reading, but some struggling readers also have a treatable eye-teaming or focusing problem that makes near work uncomfortable, and finding that is our job.

Classroom supports that lower the visual load

These help a child cope while the underlying question is sorted out. They are accommodations, not treatment.

• Extra time on reading assignments and tests, so speed does not penalize comfort.
• Scheduled breaks from near work, looking across the room between tasks.
• Print and seating: larger type, wider line spacing, a clear line of sight to the board.
• Audio and text-to-speech to carry content while reading instruction continues at full strength.
• Movement and coordination activities, which most children benefit from anyway.

Getting an answer

School screenings are worth doing and are not the whole story. The AOA’s pediatric guideline recommends a comprehensive examination before first grade and annually after, and reports that distance acuity testing alone missed 75.5% of children later found to have binocular and oculomotor problems (AOA, 2017). A developmental evaluation adds eye teaming, focusing, tracking and depth measurements to the acuity and health check.

If reading, headaches or attention at school have you wondering, a comprehensive developmental vision evaluation is the way to find out what is true for your child. Schedule an evaluation at our Boynton Beach or Boca Raton office.