CITT 2005c.

Study characteristics
Methods	Study design: RCT Number randomized: 46 (17 assigned to pencil push‐ups; 15 assigned to vergence/accommodative therapy; 14 assigned to placebo vergence/accommodative therapy) Unit of randomization: individual participant (convergence insufficiency is a binocular vision disorder) Number analyzed: 40 (87%) (15 of 17 assigned to pencil push‐ups; 12 of 15 assigned to vergence/accommodative therapy; 13 of 14 assigned to placebo vergence/accommodative therapy) Number of centers: 6 Date of first enrolment: November 2000 Length of follow‐up: planned: 12 weeks after initiation of treatment; actual: 12 ± 2 weeks after initiation of treatment Sample size estimation: no formal sample size calculations were performed a priori because one goal of this pilot trial was to estimate the variability of the outcome measure. At the study completion, using the observed variability in the Convergence Insufficiency Symptom Survey, with α=0.05, assuming a 2‐sided test, and assuming the post treatment mean of the most effective treatment group would approximate the mean among patients with normal binocular vision at 12 weeks, the mean for the placebo group would decrease 20% from its baseline value, and the mean for the other treatment group would fall in the middle of these two groups, the sample size of 46 yielded a power of 99.6%.
Participants	Country of recruitment: United States Mean age: 24.4 ± 3.4 (SD) years in the pencil push‐ups group; 23.7 ± 3.9 (SD) years in the vergence/accommodative therapy group; 25.1 ± 3.5 (SD) years in the placebo vergence/accommodative therapy group Sex: 70.6% were female in the pencil push‐ups group; 73.3% were female in the vergence/accommodative therapy group; 71.4% were female in the placebo vergence/accommodative therapy group Key inclusion criteria: age 19 to 30 years; best corrected visual acuity of 20/25 or better in both eyes at distance and near; willingness to wear eyeglasses or contact lenses to correct refractive error, if necessary; exophoria at near at least 4 Δ greater than at far; insufficient positive fusional convergence at near (i.e., failing Sheard's criterion or a positive fusional vergence measure or less than 15 Δ base‐out break); receded near point of convergence of ≥ 6 cm break; appreciation of at least 500 seconds of arc on the forms part of the Randot Stereotest; Convergence Insufficiency Symptom Survey V‐13 score ≥ 9; informed consent and willingness to participate in the study and be randomized. Key exclusion criteria: convergence insufficiency previously treated with pencil push ups, or office‐based vergence/accommodative therapy (no more than 2 months of treatment within the past year); amblyopia; constant strabismus; history of strabismus surgery; anisometropia > 1.50 D (spherical equivalent) difference between eyes; prior refractive surgery; vertical heterophoria > 1 Δ; systemic diseases known to affect accommodation, vergence, and ocular motility such as multiple sclerosis, Grave's thyroid disease, myasthenia gravis, diabetes, and Parkinsons disease; any ocular or systemic medication known to affect accommodation or vergence; monocular accommodative amplitude less than 4 D in either eye as measured by the push up method; manifest or latent nystagmus; household member already enrolled in the CITT; any eye care professional, ophthalmic technician, medical student, or optometry student.
Interventions	Intervention regimen #1: pencil push‐ups Patients in the pencil push‐ups group were taught a pencil push‐up procedure that included monitoring for suppression. Patients were instructed to hold a pencil at arm’s length directly between their eyes, and an index card, serving as a suppression control, was placed on the wall 6 to 8 feet away. Patients were instructed to look at the very tip of the sharpened pencil and to try and keep the pencil point single while moving it toward their nose. If one of the cards in the background disappeared, patients were instructed to stop moving the pencil and blink their eyes until both cards were present. Patients were told to continue moving the pencil slowly toward their nose until it could no longer be kept single and then to try and get the pencil point back into one. If patients were able to regain single vision, they were asked to continue moving the pencil closer to their nose. If patients could not get the pencil back to one, they were instructed to start the procedure again. Patients were instructed to do three sets of 20 pencil push‐ups per day at home, 5 days per week for 12 weeks, and this treatment required an average of 15 minutes per day. Prior to doing the procedure at home, the patient had to demonstrate their understanding and ability to perform the procedure according to protocol. Intervention regimen #2: office‐based vergence/accommodative therapy The vergence/accommodative therapy group received therapy administered by a trained therapist during a weekly, 60‐minute office visit, with additional procedures to be performed at home for 15 minutes a day, five times per week for 12 weeks. The items are listed elsewhere. In addition, treatment procedures were practiced at home. During a typical office‐based treatment session, the patient practiced four to five procedures with constant supervision and guidance from the therapist. There were no diagnostic tests performed during these sessions. The therapist followed a very detailed and specific CITT protocol from the manual of procedures, which described the proper treatment technique, amount of time the technique was to be used, expected performance, and criteria for ending the procedure and advancing to a more difficult level. Intervention regimen #3: placebo office‐based vergence/accommodative therapy Like the vergence/accommodative therapy group, the placebo vergence/accommodative therapy group received therapy administered by a trained therapist during a 60‐minute office visit and was prescribed procedures to be performed at home for 15 minutes, five times per week for 12 weeks. The procedures for placebo vergence/accommodative therapy were designed to simulate real vergence/accommodative therapy procedures without the expectation of affecting vergence, accommodation, or saccadic function.
Outcomes	Primary outcome: symptoms measured using Convergence Insufficiency Symptom Survey V‐15 after 12 weeks of therapy. Key secondary outcomes: near point of convergence, and positive fusional vergence at near. No harms were reported.
Notes	Funding sources: National Eye Insititute, National Insitutes of Health, Bethesda, Maryland, USA. Subgroup analyses: none reported Trial registration: NCT00347945
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"The data‐coordinating center for the study, randomly assigned eligible patients with equal probability to either pencil push‐ups, vergence/accommodative therapy, or placebo vergence/accommodative therapy. Randomization was accomplished with the study's Web site using blocks of 6 so that the investigator could not predict the sequence of treatment assignments. To ensure approximately equal numbers of patients in each treatment arm, randomization was performed separately for each site."
Allocation concealment (selection bias)	Low risk	See above.
Blinding (performance bias and detection bias) Primary outcome	Low risk	"Examiners were masked to the treatment assignment (personal communication with the lead investigator)."
Blinding (performance bias and detection bias) Secondary outcomes	Low risk	See above.
Incomplete outcome data (attrition bias) Primary outcome	Unclear risk	"All results are reported for only those patients with data at the 12‐week visit.  Further analyses were performed after imputing outcome values for patients lost to follow‐up. That is, the value at the last available examination was used for each patient who did not complete the study. For 5/6 patients who did not have outcome data at 12 weeks, the only data available were collected at baseline. When differences in statistical analyses were found, the results from analyses with imputed data are also reported."
Incomplete outcome data (attrition bias) Secondary outcomes	Unclear risk	See above.
Selective reporting (reporting bias)	Low risk	All outcomes listed in the study protocol were reported.