Manual of Procedures — Original English text, Chapters 1–11

CITT Manual of Procedures, Chapter 1. Study methods and CITT manual · Trial registration NCT00338611 · Study results.

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The Convergence Insufficiency Treatment Trial (CITT) is a prospective, masked, placebo-controlled, multi-center clinical trial in which 208 subjects between the ages of 9 to < 18 years will be randomly assigned to: 1) Home-based Pencil Push-Up Therapy, 2) Home-based Pencil Push-ups with Computer Vision Therapy/Orthoptics, 3) Office-based Vision Therapy/Orthoptics, or 4) Placebo Office-based Vision Therapy/Orthoptics. Measurements of the signs and symptoms of CI will be made at the eligibility examination, and by masked examiners after 4, 8 and 12 weeks of treatment have been completed. Long term follow-up will be assessed at 6 and 12 months after the completion of active treatment.

The primary goal is to answer the following question: After 12 weeks of treatment for CI, is Home-based Pencil Push-up therapy, Home-based Pencil Push-ups with Computer Vision Therapy/Orthoptics (VT/Orthoptics) or Office-based VT/Orthoptics more effective than placebo treatment (placebo VT/Orthoptics,) and is there a difference between the three treatments in improving subject symptoms and signs? We will test the null hypothesis that there is no difference in the outcome among the four treatment groups. If the null hypothesis is rejected, we will perform multiple comparisons between the groups to determine which differences in outcomes are significant.

The primary outcome measure is a symptom score obtained via the Convergence Insufficiency Symptom Survey. The secondary outcome measures are the near point of convergence and positive fusional vergence at near. These measures were tested and validated for this study by members of our study group under an NEI R21 Clinical Trial Planning Grant, and the CITT is powered at 90% to test differences across treatment arms for each of the outcome measures.

Effectiveness will be assessed by comparing the mean of each outcome measure (either CI Symptom Survey score, near point of convergence or positive fusional vergence) obtained at the 12-week masked examination between the four treatment groups. The results of all of these comparisons will then be synthesized into a final conclusion about the relative effectiveness of each treatment arm. If we are to conclude that Office-based VT/Orthoptics is a more effective treatment for CI than the other two treatments tested, results from our pair-wise comparisons must show that Office-based VT/Orthoptics was significantly different (and the mean indicative of a clinically-relevant improvement) than Office-based Placebo VT/Orthoptics and both of the other therapy arms. If, instead, we are to conclude that Home-based Pencil Push-ups with Computer VT/Orthoptics is the most effective, this group must be found to perform as well as or significantly better than Office-based VT/Orthoptics and significantly better (and the mean indicative of a clinically-relevant improvement) than either Home-based Pencil Push-up or Office-based Placebo VT/Orthoptics. Similarly, if Home-based Pencil Push-up therapy performs as well as or significantly better than the other three treatment groups (and the mean for Home-based Pencil Push-up therapy indicates clinically-relevant improvement), then our conclusion would be that Home-based Pencil Push-up therapy is the most effective treatment for CI.

Additional questions to be answered include: