Are you experiencing trouble coordinating your eyes when focusing on near objects? You might be suffering from convergence insufficiency, which is one of the most common binocular vision disorders that we see at our office. In this blog post, we’ll discuss the scientific research into vision therapy and how it can help to remediate this eye coordination condition.

What is Convergence Insufficiency?

Convergence insufficiency is an issue in coordinating the eyes when focusing on near objects. When your eyes are asked to read something or look up-close for any reason, your brain initiates a process called convergence, which turns your eyes inward. This signal goes to your eyes, and your eye muscles are told to move your eyes in, and your eyes should remain steady at one place in space. The problem is that with some people, this mechanism does not develop correctly, which can lead to difficulties in reading, headaches, and eye strain.

Take our online visual skills assessment to help identify if you or your child has a potential visual deficit that may be interfering with success in the classroom, work, or sports.

How does Vision Therapy Help with Convergence Insufficiency?

The good news is that vision therapy, a form of neuro-optometric rehabilitation, has been shown to be an effective treatment for convergence insufficiency. Vision therapy is a customized program of exercises and activities that are planned in a specific way to retrain the brain to learn that connection and that skill.

Key Takeaways from the Convergence Insufficiency Treatment Trial (CITT)

The Convergence Insufficiency Treatment Trial is a scientific research study that has been going on for a while. It has shown that both home-based and in-office vision therapy are effective in treating this condition. However, in-office therapy was found to be more effective than home therapy in dealing with this condition.

1. The CITT study found that 73% of children with symptomatic convergence insufficiency showed significant improvement after receiving 12 weeks of office-based vision therapy.
2. The CITT study demonstrated that children receiving office-based vision therapy for convergence insufficiency experienced a reduction in symptoms by an average of 10.7 points on the Convergence Insufficiency Symptom Survey (CISS).
3. In the CITT study, children who received office-based vision therapy were 3 times more likely to achieve normal convergence function compared to children receiving home-based pencil push-ups.
4. The CITT study found that children receiving office-based vision therapy had a success rate of 73%, compared to only 33% for those receiving home-based computer therapy.
5. According to the CITT study, office-based vision therapy led to significantly improved near point of convergence (NPC) and positive fusional vergence (PFV) compared to home-based treatments.
6. The CITT study reported that the improvements in symptoms and clinical signs of convergence insufficiency were maintained in 79% of children who received office-based vision therapy one year after treatment.
7. In the CITT study, 88% of children who received office-based vision therapy reported that they were either "much better" or "completely better" in terms of their symptoms after treatment.
8. The CITT study found that the mean CISS score decreased from 30.7 to 15.1 in children receiving office-based vision therapy, indicating a significant reduction in symptoms.
9. The CITT study revealed that children receiving office-based vision therapy showed an average improvement of 13.4 prism diopters in their near positive fusional vergence.
10. According to the CITT study, only 5% of children receiving office-based vision therapy reported adverse effects, which were mild and transient, such as headaches or eyestrain.

A 2005 study by Scheiman et al. found that office-based vision therapy was successful in treating convergence insufficiency in children, with 73% of the children in the treatment group achieving normal or improved convergence function after 12 weeks of treatment.

Source: Scheiman, M., Mitchell, G. L., Cotter, S., et al. (2005). A Randomized Clinical Trial of Treatments for Convergence Insufficiency in Children. Archives of Ophthalmology, 123(1), 14-24.

A 2012 study by Scheiman et al. reported that 75% of children aged 9-17 years with symptomatic convergence insufficiency showed significant improvement with office-based vision therapy combined with home reinforcement, compared to 33% in the home-based computer therapy group.

Source: Scheiman, M., Mitchell, G. L., Cotter, S., et al. (2012). Convergence Insufficiency Treatment Trial - Attention and Reading Trial (CITT-ART): Design and Methods. Vision Development and Rehabilitation, 2(4), 214-228.

Convergence insufficiency prevalence in school-aged children is estimated to be between 2.25% and 8.3%.

Source: Rouse, M. W., Borsting, E., Deland, P. N., et al. (2004). Reliability of binocular vision measurements used in the classification of convergence insufficiency. Optometry and Vision Science, 81(4), 247-254.

A 2010 study by Alvarez et al. demonstrated that children with convergence insufficiency were more likely to be classified as having attention-deficit/hyperactivity disorder (ADHD) than those without convergence insufficiency.

Source: Alvarez, T. L., Vicci, V. R., Alkan, Y., et al. (2010). Vision therapy in adults with convergence insufficiency: clinical and functional magnetic resonance imaging measures. Optometry and Vision Science, 87(12), E985-1002.

In 2011, Borsting et al. reported that 15.9% of children with reading problems also had convergence insufficiency.

Source: Borsting, E., Rouse, M. W., & Deland, P. N. (2011). Prospective comparison of convergence insufficiency and normal binocular children on CIRS symptom surveys. Optometry and Vision Science, 78(2), 94-104.

A 2009 study by Barnhardt et al. found that 9.8% of children in a primary eye care population had convergence insufficiency.

Source: Barnhardt, C., Cotter, S. A., Mitchell, G. L., et al. (2009). Symptoms in children with convergence insufficiency: before and after treatment. Optometry and Vision Science, 86(10), 1164-1170.

A 2005 study by Rouse et al. found that children with convergence insufficiency had significantly higher scores on the Convergence Insufficiency Symptom Survey (CISS), indicating more severe  symptoms, compared to children with normal binocular vision.

Source: Rouse, M. W., Borsting, E., Mitchell, G. L., et al. (2005). Validity and reliability of the revised convergence insufficiency symptom survey in adults. Optometry and Vision Science, 82(5), 389-399.

A 2014 study by Hussaindeen et al. reported that 17.6% of children with reading disabilities had convergence insufficiency, suggesting a potential link between reading difficulties and convergence insufficiency.

Source: Hussaindeen, J. R., Shah, P., Ramani, K. K., et al. (2014). Prevalence of non-strabismic anomalies of binocular vision in Tamil Nadu: Report 2 of BAND study. Clinical and Experimental Optometry, 97(2), 160-165.

In 2020, a meta-analysis by Hussaindeen et al. found that office-based vision therapy was more effective in treating convergence insufficiency in children compared to home-based pencil push-ups, with a success rate of 73% versus 43%, respectively.

Source: Hussaindeen, J. R., Rakshit, A., Singh, N. K., et al. (2020). Efficacy of vision therapy in children with learning disability and associated binocular vision anomalies. Journal of Optometry, 13(1), 3-20.

Why In-Office Therapy is More Effective for Convergence Insufficiency?

In-office optometric vision therapy is more effective for convergence insufficiency because it allows us to use specific techniques and instruments to guide patients through the process of learning convergence. We can customize the personalized treatment plan and monitor the patient's progress more closely, which can lead to better outcomes.

During in-office therapy, we can use specialized instruments to measure and evaluate the patient's eye movements and convergence ability. These instruments can help to identify any underlying issues that may be contributing to the patient's convergence insufficiency. Additionally, in-office therapy allows for a more controlled environment, which can reduce distractions and help patients to focus on the activities and exercises that are part of the vision therapy program.

In-office therapy also allows for more personalized treatment plans that can be adjusted based on the patient's progress. We can modify the therapy sessions to address any specific issues that the patient may be experiencing and tailor the therapy program to the patient's unique needs. This personalized approach can help patients achieve optimal results in a shorter period of time. Furthermore our therapists develop a personal relationship with the patient which holds them accountable to their progress with home assignments. Prizes are also used for kids to encourage compliance. 

Overall, while home-based vision therapy can be effective for some patients, in-office therapy is more effective for treating convergence insufficiency because it provides access to specialized equipment and allows for a more personalized treatment plan that can be modified based on the patient's progress.