Trial of Vision Therapy for Intermittent Exotropia (VT-IXT)

A Pilot Randomized Trial Evaluating Short-Term Effectiveness of Vision Therapy in Children With Intermittent Exotropia

The main objective of this randomized trial comparing vision therapy to observation is to determine the short-term effectiveness of vision therapy on distance intermittent exotropia control. The results will help determine whether to proceed to a full-scale, long-term randomized trial.

Study Overview

• Status: Recruiting
• Conditions: Intermittent Exotropia
• Intervention / Treatment: Other: Vision Therapy

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 58
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Angela Chen, OD, MS; Phone Number: 714-463-7569; Email: angelachen@ketchum.edu

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35294
      • Recruiting
      • University of Alabama in Birmingham
      • Contact: Kristine Hopkins, OD, MSPH; Phone Number: 205-996-1678; Email: kbhopkins@uab.edu
  • California
    • Fullerton, California, United States, 92831
      • Recruiting
      • Southern California College of Optometry at Marshall B. Ketchum University
      • Contact: Angela Chen, OD, MS; Phone Number: 714-463-7569; Email: angelachen@ketchum.edu
    • Stanford, California, United States, 94305
      • Recruiting
      • Stanford University
      • Contact: Tawna Roberts, OD, PhD; Phone Number: 650-723-1143; Email: tawnar@stanford.edu
  • Ohio
    • Columbus, Ohio, United States, 43210
      • Recruiting
      • Ohio State University
      • Contact: Ann Morrison, OD, MS; Phone Number: 614-247-0010; Email: morrison.421@osu.edu
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19141
      • Recruiting
      • Salus University
      • Contact: Erin Jenewein, OD, MS; Phone Number: 215-276-6053; Email: ejenewein@salus.edu
  • Tennessee
    • Memphis, Tennessee, United States, 38104
      • Recruiting
      • Southern College of Optometry
      • Contact: Marie Bodack, OD; Phone Number: 901-722-3349; Email: mbodack@sco.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 8 years to 16 years (Child)
• Accepts Healthy Volunteers: No

Description

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)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Vision Therapy; Participants will receive 20 consecutive weeks of office-based vision therapy with home therapy.	Other: Vision Therapy; 20 consecutive weeks of office-based vision therapy with home therapy that aim to improve the participant's vergence skills, accommodative skills, and sensory fusion.; Other Names: Orthoptics
No Intervention: Observation; Participants will receive no treatment for IXT is received during the study unless one of the deterioration criteria is met.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Distance Control Score	The primary analysis will be an intent-to-treat comparison of mean distance control score, determine by the intermittent exotropia office control scale, at outcome using an analysis of covariance model, which will adjust for baseline distance control. The intermittent exotropia office control scale grades the control on a scale of 0 (best control; phoria) to 5 (worst control; constant exotropia).	21 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
No Spontaneous Tropia	The proportion of participants with no spontaneous tropia at outcome will be compared between treatment groups.No spontaneous tropia is defined as control score of 2 or less on all three assessments of control at distance and near and no exotropia lasting more than 5 seconds throughout the examination.	21 weeks
Change in Distance Control	The proportion of participants with >= 1 point change in control and >= 2 points change in control will be compared between treatment groups.	21 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Vergence and Accommodative Measures	The near point of convergence, positive and negative fusional vergence ranges at distance and near, vergence facility, accommodative amplitude, and accommodative facility at outcome will be compared between treatment groups adjusting for the corresponding baseline value. The analysis will be completed separately for each vergence and accommodative measures.	21 weeks
Suppression Status	Suppression status will be compared at outcome between treatment groups, adjusting for baseline suppression status. Suppression status when the participant's eyes are in tropic position will be assessed using the suppression scale ranging from 0 (negligible suppression) to 4 (dense suppression).	21 weeks
Objective Eye Movement Recordings	Frequency of intermittent exotropia by objective eye movement recordings will be compared between treatment groups.	21 weeks

Collaborators and Investigators

• Sponsor: Southern California College of Optometry at Marshall B. Ketchum University
• Collaborators: University of Alabama at Birmingham; Stanford University; Ohio State University; Case Western Reserve University; Salus University; Southern College of Optometry; American Academy of Optometry
• Investigators: Study Chair: Angela Chen, OD, MS, Southern California College of Optometry at Marshall B. Ketchum University

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2021
• Primary Completion (Estimated): December 1, 2025
• Study Completion (Estimated): December 1, 2025

Study Registration Dates

• First Submitted: July 17, 2020
• First Submitted That Met QC Criteria: July 22, 2020
• First Posted (Actual): July 27, 2020

Study Record Updates

• Last Update Posted (Actual): November 30, 2023
• Last Update Submitted That Met QC Criteria: November 28, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Keywords: Vision Therapy; Intermittent Exotropia
• Additional Relevant MeSH Terms: Nervous System Diseases; Eye Diseases; Cranial Nerve Diseases; Ocular Motility Disorders; Strabismus; Exotropia
• Other Study ID Numbers: 20-08

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No