By David K. Wallace, MD, MPH
This randomized clinical trial is the first effort to compare three forms of vision therapy and a placebo therapy option for improving symptomatic convergence insufficiency (CI). It was conducted by the Convergence Insufficiency Treatment Trial (CITT) Group and funded by the National Eye Institute.
The 12-week study randomized 221 children, ages 9 to 17, to one of three treatment groups: standard therapy of home-based pencil pushups (HBPP), home-based computer vergence/accommodative therapy and pencil push-ups (HBBCVAT+), office-based vergence/accommodative therapy with home reinforcement (OBVAT) or office-based placebo therapy with home reinforcement (OBPT).
After 12 weeks of treatment, nearly 75 percent of children who were given the office-based vision therapy along with at-home reinforcement had significantly fewer symptoms of CI. Only 43 percent of patients who completed home-based therapy alone showed similar results, as did 33 percent of patients who used home-based pencil push-ups plus computer therapy and 35 percent of patients given a placebo office-based therapy
"Before this study by the CITT group, no adequately powered randomized clinical trial had been done to address whether office-based treatment for convergence insufficiency was more effective than the less expensive home-based therapies," writes David K. Wallace, MD, MPH, in an editorial that accompanies the results of this trial published in the Archives of Ophthalmology, October 2008.
Wallace writes that the CITT also evaluated a different approach to treating convergence insufficiency many optometrists use; one that includes office-based vision therapy, which they also refer to as vergence/accommodative therapy.
"Vision therapy has negative connotations for many ophthalmologists; this term includes many forms of office-based treatment for different conditions. Its use for some of these conditions, such as reading disabilities in children, is controversial, even among optometrists. However, the type of vision therapy for convergence insufficiency evaluated in the current study could be considered equivalent to intensive orthoptics," he writes.
But Wallace writes that he remains uncertain that office-based treatment is superior to home-based treatments.
"This study addressed 2 key questions: Is office-based vergence/accommodative therapy effective relative to placebo? How does office-based treatments compare with home-based treatments?
"The answer to the first questions is certainly "yes," as children who received office-based treatment were less symptomatic than those who received placebo office treatment, and the authors provided evidence of a successful masking of treatment group.
"The answer to the second question is not as clear. It is true there were statistically significant differences in symptom scores between the office-based group and 2 other active treatment groups. However, I remain uncertain that office-based treatment is superior to home-based treatments because I do not think that either of the home-based treatments used in this study provided an ideal comparison group. Patients in an ideal comparison group would have received the same amount of therapy at home that the office-based group received as well as equal contact time with the therapist.
Wallace's conclusion: "Is office-based therapy for symptomatic convergence insufficiency worth the additional cost? It may be for a subgroup of patients who do not achieve sufficient benefit from less expensive home-based treatments. Uncertainty remains as to whether office-based treatment would be superior to equally intensive home-based therapy...Additional studies that include more intensive and flexible home-based regiments and an evaluation of the cost-effectiveness of different treatment options are needed."
Financial Disclosures
Dr. Wallace has no financial interests to disclose.