We were unable to retrieve any research studies to support the effectiveness of non-computerized, home-based VT/orthoptics. Cooper and Feldman³⁴ used computer-based vision therapy in an operant conditioning paradigm with 8 subjects to determine if vergence therapy improved vergence amplitudes. They used an A-B reversal design. The experimental group (A) received vergence therapy, while the control group (B) did not. (Eventually the control group became the experimental group, and the experimental group became the control group). During vergence therapy a correct response resulted in the computer automatically and immediately giving the subject a positive auditory reinforcement (beep) and an automatic increase in the vergence demand. Incorrect responses resulted in an audible “boop” from the computer and a concurrent decrease in the vergence demand. Thus, the behavior of the subject controlled the vergence demand. Success was met with a harder demand, failure, with an easier task. The control group received identical stimuli and reinforcement; however, neither correct nor incorrect responses resulted in a change in the vergence demand. The results of this study demonstrated that automated computerized therapy resulted in a rapid increase of fusional vergence with concurrent transference of this ability to other vergence tasks (vectogram vergence ranges). Since fusional vergence is a measure of the patient’s ability to effectively deal with the convergence insufficiency problem, this was a favorable outcome.

Daum et al³⁵ supported Cooper and Feldman’s work by showing that vergence therapy using a computerized video display is an effective technique for increasing positive fusional vergence. Six subjects received positive vergence training using a slow vergence training rate (0.75 delta/s), and six subjects received positive vergence training using a fast vergence training rate (5.00 delta/s). Six subjects served as controls and did not receive therapy. The therapy was performed using a computerized video display. The duration of therapy was 80 min over a period of 4 weeks. All training activities were monitored. All vergence evaluations were double masked. The authors found that vergence therapy using a computerized video display is an effective technique for increasing positive fusional vergence.

Cooper and Selenow³⁶ designed an experiment to determine if computer-based orthoptics/vision therapy was successful in treating convergence insufficiency and reducing symptoms. They again used an A-B-A cross-over design with 7 subjects to control for experimental bias, placebo effects, and order effects. After the experimental phase all patients exhibited significant increases in maximum vergence compared to that recorded at baseline or the control phase. The mean increase in vergence for all seven patients was 17.7Δ (std =6.9Δ). In contrast the vergence increase after the control phase was 2.4Δ (std =4.1Δ). Statistical analysis revealed that maximum vergence scores in baseline, control and experimental phases were significantly different (F=7.75; DF=2, 12; p<0.01). It was found that therapy improved convergence amplitudes, and reduced symptoms as measured on a scaled questionnaire.

A review of the research of computerized VT/orthoptics indicates that it is an effective treatment for decreasing symptoms and improving positive fusional vergence in patients with convergence insufficiency (positive fusional vergence is one of the two secondary objective outcome measures in the CITT). While these studies used the identical software being used in the CITT, the therapy was actually administered in an office setting in these studies.

Office-based Vision Therapy/Orthoptics requires a subject to undergo a specific therapy regimen with regular office visits once or twice per week. Typically, vision therapists (O.D., M.D., orthoptists, or specially trained technicians) administer the therapy in the office. Office-based vision therapy/orthoptics is generally supplemented with various home therapy procedures as well. Approximately 10-20 office visits are necessary for most subjects.^{28, 29, 37}