Trial of Vision Therapy for Intermittent Exotropia

Vision therapy (VT) is a commonly prescribed treatment for children with intermittent exotropia (IXT). The effectiveness of VT as a treatment modality for children with IXT is unknown because previous studies have largely limited observational or retrospective case series without comparison groups. The objective of this multi-centered pilot randomized trial of VT for IXT compared to observation is to 1) determine the short-term effectiveness of VT on distance intermittent exotropia and 2) determine the feasibility of recruitment and retention of children aged 8 to 16 years old with IXT to participate in a randomized trial of 20 weeks of in-office VT. The results of this trial will provide the needed information to plan and conduct a large-scale randomized trial to determine short-term and long-term effectiveness of VT for IXT in children, with the full-scale randomized trial helping to fill in the gaps in scientific knowledge concerning VT as a treatment for IXT.

Major Inclusion Criteria-

• Age 8 - 16 years
• Intermittent exotropia meeting all of the following:

• Distance exodeviation of 15∆ to 35∆ by prism alternating cover test (PACT)
• IXT, exophoria, or orthophoria at near
• Near exodeviation that does not exceed the distance exodeviation by more than 10∆
• Mean distance control score of 2 points or more with at least one measure being 3 points or higher
• Mean near control score less than 5 points
• Random dot stereopsis of 200" or better on Preschool Randot Stereotest
• Willingness to accept randomization and no plan to relocate in the next 6 months

Major Exclusion Criteria-

• Treatment for IXT or amblyopia (other than refractive correction) within 3 months prior to enrollment
• Office-based vision therapy for IXT within 6 months prior to enrollment
• Prior office-based vision therapy for IXT of ≥10 sessions
• Prior strabismus, intraocular, or refractive surgery (including BOTOX injection)