CI is a common problem that frequently results in significant symptoms with near work. However, the best treatment for CI is not known. Therefore, a randomized trial to determine the best treatment is justified. The cost of standard, home-based pencil push-up therapy with or without computer VT/orthoptics is significantly less than office-based vision therapy/orthoptics. Thus, the greatest public health cost impact will be derived if either home-based pencil push-up therapy group is demonstrated to be as or more effective than office-based vision therapy/orthoptics. Office-based vision therapy/orthoptics involves an average of 10 to 20 office visits, while little or no in-office follow-up is typically involved in pencil push-up therapy.³⁷ The typical fee for an in-office vision therapy/orthoptics session in the United States is $75 per session. This translates to an additional cost of $1125 to $1500 per subject for in-office vision therapy/orthoptics. If pencil push-up therapy with or without computer VT/ orthoptics is proven to be as effective as or more effective than office-based vision therapy/orthoptics in the treatment of CI, there will be a substantial savings in health care expenditures. If, however, the results demonstrate that office-based vision therapy/ orthoptics is more effective than pencil push-up therapy for CI, professionals will have proven treatment algorithms with which to effectively treat this condition.

Subjects with CI and their doctors will benefit directly from the fact that this is a carefully designed systematic study with formal protocols, definitions, and procedures. The diagnosis and treatment guidelines developed in this study will provide consistency in a field replete with variability in definitions, diagnoses, and treatment practices. It will enable eye care practitioners to make more informed decisions concerning the nature of each subject’s visual dysfunction and the management procedures that would potentially be most appropriate.

All sample size calculations were performed using PASS 2000 software assuming a two-sided test with β=0.10 (i.e. 90% power). In the sample size calculations for a given outcome measure, the common standard deviation obtained from the CITT pilot study was used as an estimate of the variability. A clinically relevant difference between any two groups after 12 weeks of treatment with respect to the CI symptom score was defined as a difference in mean scores of at least 10 points. The CI symptom survey includes 15 items; this translates into scoring one response level lower on at least one-third of the survey items. This value is slightly larger than one-half the width of the 95% limits of agreement interval calculated using the CITT pilot study data. For each of the objective outcome measures, clinically relevant differences were determined by the CITT executive committee with input from other CITT study members. Information on the repeatability of each of the clinical measures was also used in the determination of clinically relevant differences.

Sample size estimates were then adjusted for potential losses to follow-up. We estimate that 10% of subjects will be lost to follow-up before the end of the study (i.e. a retention rate of 90%); a total of 47*1.1 = 52 patients will be randomly assigned to each treatment arm. By adjusting the sample sizes, we ensure the ability to detect meaningful differences between the groups in analyses that include only those subjects with week 12 data (i.e., if we choose not to use earlier masked examination data as a proxy measure for week 12).

A total of 208 CI patients will be required to ensure adequate power to detect differences if they truly exist among treatment groups after 12 weeks of active treatment. Given our conservative recruitment estimate of 3 patients every two months from each of 9 clinical sites, we should then be able to reach our goal in no more than eighteen months.

As shown in Figure 1-1, the CITT represents a collaborative effort with the following components:

An outline of the functions and composition of the study centers and committees follows

Location: The Pennsylvania College of Optometry, Philadelphia, PA

The Study Chair will: