Improving Control of Alignment in Intermittent Exotropia

Intermittent Exotropia Clinical Trial

Official title:

Improving Control of Alignment in Intermittent Exotropia

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT04199871
• Other study ID #: STU-2019-1430
• Status: Recruiting
• Phase: N/A
• Start date: March 25, 2021
• Est. completion date: December 2024

Study information

• Verified date: October 2023
• Source: Retina Foundation of the Southwest
• Contact: Eileen E Birch, PhD
• Phone: 2143633911
• Email: ebirch[@]retinafoundation.org
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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

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).

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 84
• Est. completion date: December 2024
• Est. primary completion date: December 2024
• Accepts healthy volunteers: No
• Gender: All
• Age group: 3 Years to 12 Years

Eligibility

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

Related Conditions & MeSH terms

• Exotropia
• Intermittent Exotropia

Intervention

Other:
• dichoptic 3D movies
dichoptic movies presented on a Nintendo 3DS

Locations

Country	Name	City	State
United States	Eileen E Birch	Dallas	Texas

Sponsors (1)

Lead Sponsor	Collaborator
Retina Foundation of the Southwest

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Alignment Control Score	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)	3 months
Secondary	Stereoacuity at distance	Randot Distance Stereoacuity Test	3 months
Secondary	Binocular fixation stability	Stability of the vergence angle assessed by recording eye movements during 20 sec fixation	3 months
Secondary	Stereoacuity at near	Randot Preschool Stereoacuity Test	3 months