Convergence Insufficiency Treatment Trial (CITT)


The purposes of the CITT are:

- To determine whether Home-based Pencil Push-up therapy, Home-based Pencil Push-ups with Computer Vision Therapy/Orthoptics or Office-based VT/Orthoptics more effective than placebo treatment, and whether there are differences between the three treatments in improving subject symptoms and signs.

- To evaluate whether improvements in outcome measures are still present after one year of observation.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Single (Participant)
  • Study Primary Completion Date: September 2008

Detailed Description

Convergence insufficiency is a prevalent and distinct binocular vision disorder. Typical symptoms include double vision, eyestrain, headaches, and blurred vision while reading. It affects approximately 5% of children in the United States, and may have a serious impact on an individual's performance in school, choice of jobs, and quality of life.

There is no consensus regarding the most effective treatment for convergence insufficiency. Two commonly prescribed treatments are home-based pencil push-up therapy and office-based vision therapy/orthoptics. Significant differences exist between these two treatment modalities in cost and number of office visits required, with pencil push-up therapy being less expensive and less time intensive. There have been no well-designed studies that have compared the effectiveness of these two treatments.

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. The primary outcome measure is a measure of symptoms using a 15-item survey, the CI Symptom Survey. Secondary outcome measures are two common clinical tests of the eyes' ability to converge when performing close work. Patients will be tested at the eligibility examination, and by masked examiners after 4, 8 and 12 weeks of treatment have been completed during the 12-week treatment phase. Long term follow-up will be assessed at 6 and 12 months after the completion of active treatment.


  • Behavioral: Home-based Pencil Push-Up Therapy
    • Exercise in which patients visually followed a small letter on a pencil as they moved the pencil closer to the bridge of their nose
  • Behavioral: Home-based Pencil Push-ups with Computer Vision Therapy/Orthoptics
    • Exercise in which patients visually followed a small letter on a pencil as they moved the pencil closer to the bridge of their nose combined with additional computer vision therapy
  • Behavioral: Office-based Vision Therapy/Orthoptics
    • Weekly hour-long sessions of office-based vision therapy with a trained therapist and performed at-home reinforcement exercises
  • Behavioral: Placebo Office-based Vision Therapy/Orthoptics
    • Vision activities designed to simulate office-based therapy

Clinical Trial Outcome Measures

Primary Measures

  • Measure of symptoms using a 15-item Convergence Insufficiency Symptom Survey
    • Time Frame: 12 weeks

Secondary Measures

  • Eyes’ ability to converge when performing close work
    • Time Frame: 12 weeks

Participating in This Clinical Trial

Inclusion Criteria

  • Children between the ages of 9 and 17 years with symptomatic convergence insufficiency
  • Exophoria at near at least 4Δ greater than at far
  • Insufficient positive fusional convergence at near
  • A receded near point of convergence of ≥6 cm break
  • CI Symptom Survey score ≥16

Exclusion Criteria

  • Previous treatment with office-based vision therapy/orthoptics or pencil push-ups
  • Systemic diseases known to affect accommodation, vergence and ocular motility
  • Developmental disability, mental retardation, attention deficit hyperactivity disorder (ADHD), or learning disability diagnosis that in the investigator's discretion would interfere with treatment

Gender Eligibility: All

Minimum Age: 9 Years

Maximum Age: 18 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • National Eye Institute (NEI)
  • Provider of Information About this Clinical Study
    • Mitchell Scheiman, OD, Pennsylvania College of Optometry
  • Overall Official(s)
    • Mitchell Scheiman, OD, Study Chair, Pennsylvania College of Optometry

Citations Reporting on Results

Convergence Insufficiency Treatment Trial Study Group. Randomized clinical trial of treatments for symptomatic convergence insufficiency in children. Arch Ophthalmol. 2008 Oct;126(10):1336-49. doi: 10.1001/archopht.126.10.1336.

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