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Improving Control of Alignment in Intermittent Esotropia

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT04199871
Recruitment Status : Not yet recruiting
First Posted : December 16, 2019
Last Update Posted : December 16, 2019
Information provided by (Responsible Party):
Eileen Birch, Retina Foundation of the Southwest

Brief Summary:
Aim 1: To determine whether use of dichoptic movies for 4 weeks may be helpful in improving control of alignment in children with intermittent exotropia (IXT), thus allowing IXT to be managed non-surgically Aim 2: To determine pre-IXT surgery use of dichoptic movies for 4 weeks post-operatively may be helpful in maintaining successful control of alignment in children who have surgical correction of IXT

Condition or disease Intervention/treatment Phase
Intermittent Exotropia Other: dichoptic 3D movies Not Applicable

Detailed Description:

The most common childhood-onset exotropia is intermittent exotropia (IXT). IXT is an exotropia that is not constant and is mainly present at distance, but may also be present at near. Binocular single vision is typically present at near but may be subnormal. There is some debate in the literature about whether or not these children should be treated surgically to correct the misalignment. It can be argued that prompt surgical correction is necessary to prevent the development of suppression of the deviating eye, progression to constant exotropia, and permanent changes in sensory function that may compromise long-term post-operative outcomes. On the other hand, statistics on the natural history of IXT suggest that progression to constant XT occurs in less than 25% and up to 15% may improve spontaneously. These findings suggest a more conservative approach, using surgery only if deterioration of the IXT occurs. A recent randomized clinical trial of the two most common surgical techniques for IXT revealed a 3-year postoperative failure rate of approximately 40% (PEDIG 2019; Ophthalmology 126: 305-17). For the vast majority of children, surgical failure was due to recurrence of the exodeviation. Only about 30% of treated children had resolution of IXT at the 3-year visit. Similarly, a literature review of 28 surgical studies that included 2530 children with IXT reported a suboptimal surgical outcome at 1-year post-op in approximately 40% of children. (Coffey et al 1992; Optom Vis Sci 69: 386-404).

Poor surgical results for IXT are thought to occur due to poor sensory status (suppression) or inadequate motor alignment. There are few data on the effects of non-surgical interventions designed to improve sensory status of children undergoing surgery for IXT. Although several retrospective case reviews found evidence supporting a benefit of pre-op sensory and motor fusion training on IXT surgical outcomes, there have been no prospective studies or randomized clinical trials. One of the largest retrospective case series (Cooper & Leyman 1977; Am Orthoptic J 27:61-7) compared 216 patients with IXT who had sensory and motor fusion training prior to surgery with 264 who had surgery alone and found a higher rate of good surgical outcomes (52% vs 42%). There are no published data on post-op interventions to improved sensory status.

In this study, engaging movies will be presented on a handheld Nintendo to decrease suppression and engage stereoacuity. In previous research, use of dichoptic games and movies by children with amblyopia has been shown to reduce suppression and encourage sensory fusion (Birch et al 2015, JAAPOS 19:6-11; Birch et al 2019, JAAPOS [Epub ahead of print]; Kelly, Jost, et al 2016; JAMA Ophthalmol 134:1402-8.; Kelly et al Invest 2018 Ophthalmol Vis Sci 59:1221-8; Li et al 2014; Eye 28: 1246-53). This approach will be adapted by using dichoptic movies presented on a Nintendo for children with IXT to improve their stereoacuity and reduce their suppression in an effort improve control of alignment sufficiently without surgery (Aim 1) or to improve stability of post-operative alignment (Aim 2).

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 84 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Participant)
Primary Purpose: Treatment
Official Title: Improving Control of Alignment in Intermittent Esotropia
Estimated Study Start Date : January 2020
Estimated Primary Completion Date : December 2021
Estimated Study Completion Date : January 2022

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Group1
dichoptic 3D movies
Other: dichoptic 3D movies
dichoptic movies presented on a Nintendo 3DS
Other Name: dichoptic standard movies

Sham Comparator: Group 2
dichoptic standard movies
Other: dichoptic 3D movies
dichoptic movies presented on a Nintendo 3DS
Other Name: dichoptic standard movies

Primary Outcome Measures :
  1. Alignment Control Score [ Time Frame: 3 months ]
    Classification system developed by PEDIG to quantify the degree of control of ocular alignment on a 0-5 scale at distance and near; 0 is best control [no exotropia unless dissociated, recovers in <1 second (phoria)] and 5 is worst control (constant exotropia)

Secondary Outcome Measures :
  1. Stereoacuity at distance [ Time Frame: 3 months ]
    Randot Distance Stereoacuity Test

  2. Binocular fixation stability [ Time Frame: 3 months ]
    Stability of the vergence angle assessed by recording eye movements during 20 sec fixation

  3. Stereoacuity at near [ Time Frame: 3 months ]
    Randot Preschool Stereoacuity Test

Information from the National Library of Medicine

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Ages Eligible for Study:   3 Years to 12 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • diagnosis of IXT
  • IXT control assessment score at distance of 3 or 4 at baseline
  • Ocular misalignment by PACT >10 pd at distance and near or PACT >15 at distance or near

Exclusion Criteria:

  • Amblyopia
  • Prior surgery
  • Prior binocular treatment
  • Coexisting ocular or systemic condition
  • Developmental delay

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT04199871

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Contact: Eileen E Birch, PhD 2143633911
Contact: Reed M Jost, MS 2143633911

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United States, Texas
Eileen E Birch
Dallas, Texas, United States, 75231
Sponsors and Collaborators
Retina Foundation of the Southwest
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Responsible Party: Eileen Birch, Senior Research Scientist, Retina Foundation of the Southwest Identifier: NCT04199871    
Other Study ID Numbers: STU-2019-1430
First Posted: December 16, 2019    Key Record Dates
Last Update Posted: December 16, 2019
Last Verified: December 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Ocular Motility Disorders
Cranial Nerve Diseases
Nervous System Diseases
Eye Diseases