Studies: Vision Therapy

A Randomized Clinical Trial of Treatments for Convergence Insufficiency in Children

In 2005, The Convergence Insufficiency Treatment Trial (CITT) Study Group set out to compare the effectiveness of vision therapy, pencil pushups and placebo vision therapy in the treatment of symptomatic convergence insufficiency. To measure the success of treatment, investigators looked at the following:

Symptom score of the Convergence Insufficiency Symptom Survey (CISS)
Near point of convergence
Positive fusional vergence at near

At baseline, the symptoms and clinical measurements were similar between the three treatment groups. Following 12 weeks of treatment, the CISS was again administered and measurements of near point of convergence and positive fusional vergences at near were repeated. The results of the treatment trial can be summarized as follows:

“Symptoms, which were similar in all groups at baseline, were significantly reduced in the vision therapy/orthoptics group but not in the pencil pushups or placebo vision therapy groups”
“Only patients in the vision therapy/orthoptics group demonstrated both statistically and clinically significant changes in the clinical measures of near point of convergence and positive fusional vergence at near”

At that time, the researches concluded that “Vision therapy was more effective than pencil pushups or placebo vision therapy in reducing symptoms and improving signs of convergence insufficiency in children 9-18 years of age.”

Randomized Clinical Trial of Treatments for Symptomatic Convergence Insufficiency in Children

In 2008, the Convergence Insufficiency Treatment Trial Study Group continued their work investigating the effectiveness of various approaches in the treatment of convergence insufficiency. During this randomized clinical trial, the following treatment methods were compared:

Home-based pencil pushups
Home-based computer vergence/accommodation therapy and pencil pushups
Office-based vergence/accommodation therapy with home reinforcement
Office-based placebo therapy with home reinforcement

Consistent with the design of their 2005 clinical trial “A Randomized Clinical Trial of Treatments for Convergence Insufficiency in Children”, the investigators administered the Convergence Insufficiency Symptom Survey (CISS) and measured near point of convergence and positive fusional vergence at near.

Following 12 weeks of treatment, re-assessment of the specified outcome measures revealed the following:

The office-based vergence/accommodation therapy with home support group had a Convergence Insufficiency Symptom Survey (CISS) score significantly lower than that of the other 3 treatment groups.
The office-based vergence/accommodation therapy with home support group also showed significant improvement in the near point of convergence compared to the other treatment groups
The office-based vergence/accommodation therapy with home support group also demonstrated significant improvement in the positive fusional vergence at near compared to the other groups.
The office-based vergence/accommodation therapy with home support group had the highest rate of success (73%) out of any treatment group
The computer-based therapy group had the least number of successful participants (33%) out of any group.

Based on the results of this clinical trial, the CITT Study group made the following conclusion:

“Twelve weeks of office-based vision therapy with home reinforcement results in a significantly greater improvement in symptoms and clinical measures of near point of convergence and positive fusional vergence and a greater percentage of patients reaching the predetermined criteria of success compared to home-based pencil pushups, home-based computer vergence/accommodative therapy and pencil pushups, and office-based placebo therapy with home reinforcement.”

Based on the results of the CITT Study Group's clinical trials, the National Eye Institute reported the results as a "More Effective Treatment Identified for Common Childhood Vision Disorder"

A Randomized Clinical Trial of Vision Therapy/Orthoptics Versus Pencil Pushups for the Treatment of Convergence Insufficiency in Young Adults

In 2005, a study group compared vision therapy, pencil pushups, and placebo therapy as treatments for symptomatic young adults (19-30 years of age) with convergence insufficiency.

Prior to treatment, the Convergence Insufficiency Symptom Survey (CISS) was administered and both the near point of convergence and positive fusional vergence at near were measured. Similar to the design of other clinical trials in the area of convergence insufficiency, 12 weeks of therapy was administered and the same clinical measures were re-evaluated. Here is what the researches found in this group of young adults age 19-30 years of age:

“Only patients in the vision therapy/orthoptics group demonstrated statistically and clinically significant changes in the near point of convergence and positive fusional vergence at near.”

Treatment of Accommodative Dysfunction in Children: Results From a Randomized Clinical Trial

During their investigations of convergence insufficiency, the Convergence Insufficiency Treatment Trial Study Group also evaluated the effectiveness of the various treatment modalities in improving accommodative amplitude and accommodative facility in children with symptomatic convergence insufficiency and co-existing accommodative dysfunction.

Published in 2011, this article indicated that during their clinical trials, the CITT Study Group found 74% of their subjects with convergence insufficiency to have accommodative dysfunction.

29% had accommodative insufficiency (reduced amplitdude of accommodation compared to age-appropriate norms)
19% had accommodative infacility (reduced ability to quickly change focus)
26% had both accommodative insufficiency and accommodative infacility

After 12 weeks of treatment with either:

Office-based vergence/accommodation therapy with home reinforcement
Home-based computer vergence/accommodation therapy
Home-based pencil pushup therapy

The amplitude of accommodation and accommodative facility were re-assessed. The results are as follows:

The office-based vision therapy group showed the largest increase in amplitude of accommodation, indicating the most improvement in accommodative insufficiency.
The office-based vision therapy group also showed the largest improvement in accommodative facility.
Only the improvement by the office-based vision therapy group was found to be significantly greater than that found in the placebo group.

The researchers were then able to make the following conclusion:

“Vision therapy/orthoptics is effective in improving accommodative amplitude and accommodative facility in school-aged children with symptomatic convergence insufficiency and accommodative dysfunction.”

Studies: Vision Therapy