Widmer 2018.

Study characteristics
Methods	Study design: RCT Number randomized: 7 (4 assigned to office‐based vergence‐accommodative therapy group; 3 assigned to control group) Unit of randomization: individual participant (convergence insufficiency is a binocular vision disorder) Number analyzed: 7 (100%) Number of centers: 1 Date of first enrolment: not reported Length of follow‐up: planned: 12 weeks; actual: 12 weeks Sample size estimation: not reported
Participants	Country of recruitment: United States Mean age: 26.1 ± 2.5 (SD) years Sex: 86% were female Key inclusion criteria: Participants aged 18 to 30 years; best‐corrected visual acuity of 20/25 or better in each eye at distance and near; exophoria at near ≥ 4 Δ greater than distance; receded near point of convergence of ≥ 6 cm break; reduced positive fusional vergence (less than twice the near phoria OR < 15 Δ base‐out blur, or break if no reported blur); CISS ≥ 21; accommodative amplitude ≥ 5 D; random‐dot stereopsis of at least 500 seconds of arc; cycloplegic refraction within the past 3 months; wearing any needed refractive error correction for at least 2 weeks prior to eligibility; willingness to discontinue any base‐in prism or plus add wear; access to computer with Internet to perform the computerized home therapy procedures; willingness to be randomized into either the active or placebo therapy; presumptive ability to successfully complete fMRI scanning; No previous treatment with vision therapy; not personally or living with an eye‐care professional, ophthalmology/optometry student/resident, ophthalmic technician, or employed in an eye care setting; no household member enrolled in any vergence therapy study or currently completing vision therapy Key exclusion criteria: Amblyopia; constant strabismus; vertical phoria >1 Δ; refractive surgery manifest or latent nystagmus; refractive error (not corrected by contact lenses) beyond the range of the fMRI safe trial lens set; systemic diseases known to affect accommodation, vergence, or ocular motility; current use of any medication known to affect accommodation, vergence, or ocular motility, history of brain injury, neurological disease, or any condition that may be in conflict with obtaining normal fMRI scans; pregnancy; presence of a pacemaker or any metallic implant that might be incompatible with fMRI safety; developmental or learning disability that may interfere with treatment; left‐handed dominance
Interventions	Intervention #1: office‐based vergence‐accommodative therapy "Each therapy visit consisted of 55 to 60 minutes of procedures, questions, and homework instructions. Subjects were asked to perform home reinforcement procedures 15 minutes a day, 5 days a week.Office‐based vergence‐accommodative therapy subjects completed therapy designed to stress vergence and accommodative abilities." Intervention #2: office‐based placebo therapy (No‐vergence) "...placebo subjects completed placebo therapy that did not involve vergence or accommodation beyond that involved in normal near tasks"
Outcomes	Primary outcome: Changes in brain activation (using the blood oxygenation level–dependent signal from fMRI) following office‐based vergence/accommodative therapy versus placebo therapy Key secondary outcomes: Success as defined as meeting all three of the following criteria: Convergence Insufficiency Symptom Survey (CISS) score < 21 points, normal near point of convergence (< 6 cm), and normal positive fusional vergence (> 15 Δ base‐out and at least twice the near phoria) after 12 weeks of therapy. No harms were reported.
Notes	Funding sources: Beta Sigma Kappa‐College of Optometristsin Vision Development Research Grant; Wright State University Research Initiation Grant; Optometric Educators Incorporated; Ohio Lions Eye Research Foundation Fellowship Program; Center for Cognitive and Behavioral Brian Imaging, Phychology Department, Ohio State University; Home Therapy Solutions, Gold Canyon, Arizona (home reinforcement therapy) Subgroup analyses: none reported Trial registration: not available
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"After completion of the baseline functional magnetic resonance imaging scan, each subject was randomized to 12 weeks of weekly office‐based vergence‐accommodative therapy or office‐based placebo therapy."
Allocation concealment (selection bias)	Low risk	Allocation was adequately concealed (personal communication with the investigator).
Blinding (performance bias and detection bias) Primary outcome	Low risk	"After 12 weeks of therapy, an examiner masked to the subject's assigned treatment group performed the primary outcome vision testing and functional magnetic resonance imaging scans."
Blinding (performance bias and detection bias) Secondary outcomes	Low risk	"After 12 weeks of therapy, an examiner masked to the subject's assigned treatment group performed the primary outcome vision testing and functional magnetic resonance imaging scans."
Incomplete outcome data (attrition bias) Primary outcome	Low risk	No loss to follow up in either arm.
Incomplete outcome data (attrition bias) Secondary outcomes	Low risk	See above
Selective reporting (reporting bias)	Unclear risk	No mention of pre‐specified protocol or registration for verification.

CITT: Convergence Insufficiency Treatment Trial; HBPP: Home‐based pencil push‐ups; HBCVAT+: Home‐based computer vergence/accommodative therapy and pencil push‐ups; OBVAT: Office‐based vergence/accommodative therapy with home reinforcement; OBPT: Office‐based placebo therapy with home reinforcement; RCT: Randomized controlled trial; SD: Standard deviation