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Treatment for common vision disorder does not improve children’s reading skills

NIH-funded study finds therapy for convergence insufficiency is no better at improving reading than placebo
October 23, 2019
Child reading book with one hand covering an eye

Image courtesy of Lisa Jordan, Ph.D., The Ohio State University.

Results from a clinical trial funded by the National Eye Institute (NEI) show that while vision therapy can successfully treat convergence insufficiency (CI) in children, it fails to improve their reading test scores. Investigators from the Convergence Insufficiency Treatment Trial – Attention and Reading Trial (CITT-ART) published the results online today in Optometry and Vision Science. NEI is part of the National Institutes of Health.

CI is a common childhood vision disorder in which the eyes are unable to work together when looking at nearby objects, and the condition can make tasks like reading difficult. Eye care providers who treat CI have assumed that successful vergence/accommodative therapy, often called vision therapy, would lead to better reading fluency and comprehension.  

 “While in-office vision therapy can improve visual function for children with CI, this trial indicates that clinicians should not suggest that it will lead to increased reading performance,” said lead study author Mitchell Scheiman, O.D., Ph.D., Salus University, Elkins Park, Pennsylvania.

When reading or performing other close work, the eyes must turn inward to converge. For children with CI, the eyes have difficulty converging accurately, which can lead to blur or double vision, causing symptoms like discomfort and difficulty maintaining concentration when reading. Results from the earlier Convergence Insufficiency Treatment Trial (CITT), published in Ophthalmology in 2008, showed office-based vision therapy to be the most effective treatment for improving convergence and ameliorating symptoms, and that treatment effects were long-lasting. This new clinical trial, CITT-ART, was designed to determine whether treating symptomatic CI would improve reading skills.

The study enrolled 310 children with symptomatic CI, ages 9 to 14 years, and randomly assigned them to two groups. About two-thirds (206) received in-office vision therapy for 16 weeks, and the remainder (104) received in-office placebo therapy for 16 weeks. The in-office vision therapy was designed to improve accommodation (focusing) and vergence (eye teaming, meaning the ability of the eyes to work together), while the placebo therapy procedures were designed to have no effect on CI.

The children’s reading performance and clinical signs of CI were measured when the study began and again after completing 16 weeks of therapy. Reading comprehension was assessed using the Wechsler Individual Achievement Test- Version 3 (WIAT-III). Additional assessments included word reading and pseudoword decoding (sounding out fake words), as well as oral and silent reading fluency. Clinical signs included measures of how well the eyes work together to converge on near objects. Symptoms were measured using the Convergence Insufficiency Symptom Survey.

While all children showed improved reading comprehension on the WIAT after 16 weeks, there was statistically no difference between average reading improvement for the CI treatment group (3.68 points) and placebo group (3.80 points). Nor was in-office vision therapy better than the placebo therapy on other standardized reading tests. Meanwhile, 75-80% of children in the vision therapy group had shown significant improvement and fell into the normal range for clinical signs, compared with approximately 30% in the placebo group. These results are similar to the original CITT study. However, the latest findings show no significant difference in symptoms, with 62% of children in the vision therapy group versus 58% of children in the placebo therapy group reporting significant symptom improvement. These findings suggest that clinical measures, rather than self-reported symptoms, are critical for assessing CI severity and improvement in children.

The study was supported by National Eye Institute grant U10-EY022599. More information about the clinical trial (NCT 02207517) can be found at

For more information about convergence insufficiency, visit:


Scheiman MM, Denton C, Borsting E, Kulp M, Mitchell LG, Cotter S, Chase C, Jones-Jordan L, Arnold E, Hertle R, Gallaway M, Schulman E, Tamkins S, Hopkins K, Coulter R, Roberts T, amd Iorenzana I. “Effect of Vergence/Accomodative Therapy on Reading in Children with Convergence Insufficiency: A Randomized Clinical Trial.” Nov, 2019. Optometry and Vision Science. doi:10.1097/OPX.0000000000001442 Scheiman, Denton et al. Pubmed

Scheiman MM, Cotter S, Kulp M, Mitchell LG, Jones-Jordan L, Gallaway M, Borsting E, Hertle R, Chase C, Schulman E, Tamkins S, Hopkins K, Coulter S, Lorenzana I, Roberts T, Arnold E, Sinnott L, and Denton C. “Treatment of Symptomatic Convergence Insufficiency in Children Enrolled in the Convergence Insufficiency Treatment Trial-Attention & Reading Trial: A Randomized Clinical Trial.” Nov, 2019. Optometry and Vision Science. doi:10.1097/OPX.0000000000001443 Scheiman, Cotter et al. Pubmed


NEI leads the federal government’s research on the visual system and eye diseases. NEI supports basic and clinical science programs to develop sight-saving treatments and address special needs of people with vision loss. For more information, visit

About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

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Lesley Earl