ClinicalTrials.gg
CompletedNCT01032603IXT1Updated Jul 9, 2026Results posted

Bilateral Lateral Rectus Recession Versus Unilateral Recess-Resect for Intermittent Exotropia

An interventional study of Bilateral lateral rectus recession (BLRc) and Unilateral lateral rectus recession with medial rectus resection (R&R) in Exotropia, sponsored by Jaeb Center for Health Research. Completed at 1 site in United States. Open to participants aged 3 Years to 10 Years. Per ClinicalTrials.gov, last updated 2026-07-09.

Sponsored by Jaeb Center for Health Research · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
197
Allocation
Randomized
Ages
3 Years to 10 Years
Sex
All
01

Study summary

The purpose of this study is to evaluate the effectiveness of bilateral lateral rectus muscle recession versus unilateral lateral rectus recession with medial rectus resection procedures for the treatment of basic type and pseudo divergence excess type intermittent exotropia.

Read the detailed description

Intermittent exotropia (IXT) is the most common form of childhood onset exotropia with an incidence of 32.1 per 100,000 in children under 19 years of age. Intermittent exotropia is characterized by an exotropia that is not constant and is mainly present when viewing at distance, but may also be present at near. Normal binocular single vision (BSV) is typically present at near when the exotropia is controlled, with evidence of normal (occasionally sub-normal) stereoacuity. Although the natural history of the condition is largely unknown, many children with IXT are treated using either surgical or non-surgical interventions. The rationale for intervention in childhood IXT is that extended periods of misalignment may lead to entrenched suppression, resulting in loss of BSV. Intervention may also aim to address the social effects caused by the appearance of misaligned eyes. Many children treated for IXT are currently treated surgically.

There is poor agreement as to which type of surgery is most effective for the correction of IXT and the debate has long been related to differentiation between IXT sub-types. Based on distance-near angle disparity, IXT sub-types are classified as: 1) basic (similar magnitude of misalignment at distance and near); 2) true divergence excess (larger at distance); 3) pseudo divergence excess (initially larger at distance, but near angle increases following occlusion or with addition of plus lenses at near); 4) convergence insufficiency (larger at near). Basic and pseudo divergence excess appear to be the most common of the sub-types, and are also the types for which there is most disagreement regarding the optimum surgical approach. The two most common procedures are bilateral lateral rectus recession (BLRrec) and unilateral lateral rectus recession combined with a medial rectus resection in the same eye (R\&R). Traditionally, BLRrec has been advocated where there is a larger distance angle, and R\&R where there is a similar angle at distance and near. A survey of American strabismus surgeons published in 1990 found that the majority performed BLRrec for both basic and divergence excess types. Similarly, we found by polling our investigator group that the majority still perform a BLRrec for basic type IXT. Nevertheless, controversy still exists as to which of these surgical approaches is superior. Advocates of the BLRrec procedure tend to hold that surgery should be based purely on the distance angle of deviation. Proponents of R\&R surgery suggest resection of the medial rectus best addresses the exodeviation at near.

The proposed advantage of the R\&R procedure is that resecting the medial rectus, with a possible longer term initial overcorrection, is necessary for a stable and superior long-term outcome. Nevertheless, those who favor the BLRrec procedure suggest that the more profound and prolonged initial overcorrection occurring with R\&R is not only unnecessary, but may in fact be harmful. A persistent overcorrection may be associated with the development of diplopia, amblyopia, and loss of stereoacuity. On the other hand, critics of the BLRrec procedure suggest that long-term recurrence rates are higher. Poor motor outcomes are likely to require reoperation and therefore the long-term success rates of these surgeries have public health importance in terms of cost to society.

Evaluating initial and long-term surgical outcomes in the proposed randomized clinical trial (RCT) will answer questions regarding the failure rates of these surgeries and also provide needed data on the potential harm of each procedure.

Only one prospective randomized clinical trial addresses success rates of BLRrec versus R\&R for IXT. After between 12-15 months of follow up, 82% of 17 patients undergoing an R\&R had a satisfactory outcome compared to 52% of 19 patients undergoing a BLRrec. Nevertheless, there are some important limitations of this previous study. The sample size was very small. The study population was a sub-group of patients with basic type IXT, excluding patients with basic IXT whose angle of deviation increased at far distance or following occlusion, thus limiting the generalizability of the results. In addition, outcomes were assessed unmasked, potentially biasing the results. One observational study of 103 patients (90% of whom had basic type IXT) found 1-year success rates of 56% for BLRrec and 60% for R\&R. A retrospective study of 115 patients with basic type IXT reported success rates of 69% for BLRrec and 77% for R\&R after an average of 15 months of follow up. Other studies comparing surgery types are limited not only by retrospective study design but also by inclusion of other types of exotropia, making it difficult to interpret results. In addition, many different criteria for success are used, precluding meaningful comparison of success rates between studies. This lack of evidence makes it very difficult to counsel parents of children with IXT regarding the likely success and complication rate of either procedure, limiting our ability to make informed management decisions. Establishing the respective failure rates through the proposed study will allow physicians to offer patients the type of surgery with the highest chance of long-term success, minimizing suboptimal results and repeat surgeries.

The present study is being conducted to compare the effectiveness of BLRrec with R\&R for the surgical treatment of basic type and pseudo divergence excess type IXT.

02

Conditions studied

  • Exotropia

Keywords

  • IXT
  • Exotropia
  • Strabismus
  • Intermittent exotropia
03

In context

Exotropia

58 studies on the registry are indexed under Exotropia; 13 are open to participants now.

This study's enrollment of 197 is above the median of 50 across 49 interventional studies indexed under Exotropia.

Browse Exotropia studies →

Lead sponsor

Jaeb Center for Health Research is the lead sponsor of 129 studies on the registry; 16 are open to participants now.

Of its 17 completed or terminated interventional studies of FDA-regulated products, 15 (88%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
3 Years to 10 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Age 3 to \< 11 years
  • Intermittent exotropia (manifest deviation) meeting all of the following:

    • Intermittent exotropia at distance OR constant exotropia at distance and either intermittent exotropia or exophoria at near
    • Largest exodeviation at either distance, near OR remote distance between 15 and 50 prism diopters (PD) (inclusive) by prism and alternate cover test (PACT)
    • Exodeviation at least 15 PD at distance and near by PACT
    • Basic type or pseudo divergence excess type
  • Stereoacuity of 400 arcsec or better at near by Preschool Randot stereotest (better of 2 measures)
  • Visual acuity in the worse eye at least 0.3 logMAR (20/40 on ATS HOTV or 70 letters on E-ETDRS)
  • No interocular difference of visual acuity more than 0.2 logMAR (2 lines on ATS HOTV or 10 letters on E-ETDRS testing)
  • Absence of high AC/A ratio (exclude > 6:1)
  • No previous intraocular surgery, strabismus surgery, or botulinum toxin treatment
  • Investigator planning to perform surgery for correction of IXT
  • No hyperopia greater than +3.50 D spherical equivalent (SE) in either eye

Exclusion criteria

Exclusion Criteria:

  • Coexisting vertical deviation, oblique muscle dysfunction, dissociated vertical deviation (DVD), or A or V pattern, any of which the investigator plans to address with vertical transposition of horizontal rectus muscles, oblique surgery, or vertical rectus muscle surgery, i.e., only small vertical deviations, oblique muscle dysfunction, DVD, and A or V patterns not requiring surgery are allowed
  • Limitation of ocular rotations due to restrictive or paretic strabismus
  • Craniofacial malformations affecting the orbits
  • Interocular visual acuity difference of more than 0.2 logMAR (2 lines on ATS HOTV for patients 3 to \< 7 years old or 10 letters on E-ETDRS for patients ≥ 7 years old) and/or investigator plans to initiate amblyopia treatment at this time.
  • High AC/A ratio (exclude > 6:1 by gradient method)
  • Prior strabismus surgery or botulinum toxin injection
  • Ocular disorders that would reduce visual acuity (except refractive error)
  • Prior intraocular or refractive surgery
  • Significant neurological impairment such as cerebral palsy. Patients with mild speech and/or learning disabilities are eligible.
  • Investigator planning to change refractive correction at this time (if the patient is otherwise eligible, the investigator should consider prescribing refractive correction and bringing the patient back at a later time for enrollment).
05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Outcomes assessor)
Enrollment
197 participants (actual)

Study arms

  • Active comparator
    Bilateral lateral rectus recession

    Bilateral lateral rectus recession surgery

    Procedure: Bilateral lateral rectus recession (BLRc)

  • Active comparator
    Unilateral lateral rectus recession

    Unilateral lateral rectus recession w/ medial rectus resection surgery

    Procedure: Unilateral lateral rectus recession with medial rectus resection (R&R)

Interventions

  • ProcedureBilateral lateral rectus recession (BLRc)

    Bilateral lateral rectus recession surgery

    Also known as: BLR, BLRc

  • ProcedureUnilateral lateral rectus recession with medial rectus resection (R&R)

    A unilateral lateral rectus recession combined with a medial rectus resection in the same eye. Choice of eye at investigator discretion based on any interocular difference, position under anesthesia, fixation preference, or forced duction testing. Reason for choice of eye will be recorded.

    Also known as: R&R

06

What researchers measure

Primary outcomes

  1. Number of Participants With Suboptimal Surgical Outcome as Assessed by Motor Alignment and Stereoacuity at Near by 3 Years

    A participant's intermittent exotropia (IXT) was considered to be a suboptimal surgical outcome if at any visit occurring 6 months or later, ANY of the following criteria are present by masked examiner testing: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest Participants who underwent reoperation (or treatment with botulinum toxin) without first meeting any of the above suboptimal surgical outcome criteria were also counted as suboptimal surgical outcomes in the primary analysis.

    Time frame: 3 years

  2. Primary Outcome Measure Stratified by Sex

    NIH-required analysis. Primary OM (stratified by sex): A participant's intermittent exotropia (IXT) was considered to be a suboptimal surgical outcome if at any visit occurring 6 months or later, ANY of the following criteria are present by masked examiner testing: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest Participants who underwent reoperation (or treatment with botulinum toxin) without first meeting any of the above suboptimal surgical outcome criteria were also counted as suboptimal surgical outcomes in the primary analysis

    Time frame: 3 years

  3. Primary Outcome Measure Stratified by Race

    NIH-required analysis. Primary OM stratified by race: A participant's intermittent exotropia (IXT) was considered to be a suboptimal surgical outcome if at any visit occurring 6 months or later, ANY of the following criteria are present by masked examiner testing: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest Participants who underwent reoperation (or treatment with botulinum toxin) without first meeting any of the above suboptimal surgical outcome criteria were also counted as suboptimal surgical outcomes in the primary analysis

    Time frame: 3 years

  4. Primary Outcome Measure Stratified by Ethnicity

    NIH-required analysis. POM stratified by ethnicity: A participant's intermittent exotropia (IXT) was considered to be a suboptimal surgical outcome if at any visit occurring 6 months or later, ANY of the following criteria are present by masked examiner testing: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest Participants who underwent reoperation (or treatment with botulinum toxin) without first meeting any of the above suboptimal surgical outcome criteria were also counted as suboptimal surgical outcomes in the primary analysis

    Time frame: 3 years

Secondary outcomes

  1. Patients With Exotropia by 3 Years

    Exotropia ≥10Δ by simultaneous prism and cover test (SPCT) at distance or near, confirmed by a retest, by 3 years. Criteria was met before any reoperation, and regardless of whether suboptimal surgical outcome was met by another criteria.

    Time frame: Enrollment to 3 years

  2. Patients With Constant Esotropia by 3 Years

    Constant esotropia ≥6Δ by simultaneous prism and cover test (SPCT) at distance or near, confirmed by a retest, by 3 years. Criteria was met before any reoperation, and regardless of whether suboptimal surgical outcome was met by another criteria.

    Time frame: Enrollment to 3 years

  3. Number of Participants With Stereo Loss by 3 Years

    Decrease in Preschool Randot near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest, by 3 years. Criteria was met before any reoperation, and regardless of whether suboptimal surgical outcome was met by another criteria.

    Time frame: Enrollment to 3 years

  4. Number of Participants With Exotropia Control at Distance at 3 Years

    Exotropia control at distance was assessed in all patients who completed the 3-year visit. Numeric values for exotropia control were assigned so that the following seven categories were created: Not applicable (no exodeviation) (0) No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia

    Time frame: 3 years after enrollment

  5. Mean Distance Control at 3 Years

    Mean exotropia control at distance was assessed in all patients who completed the 3-year visit. All 3-year visit data will be analyzed regardless of what treatment(s) a patient has received and regardless of whether the patient has undergone reoperation. Control at distance was analyzed as a continuous variable and compared between treatment groups using analysis of covariance (ANOVA) models that adjust for the corresponding baseline value (e.g. ANCOVA model of 3-year distance control will adjust for baseline distance control). Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

    Time frame: 3 years after enrollment

  6. Change in Distance Exotropia Control at 3 Years

    Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement. Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

    Time frame: Enrollment to 3 years

  7. Number of Participants With Exotropia Control at Near at 3 Years

    Exotropia control at near was assessed in all patients who completed the 3-year visit. Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

    Time frame: 3 years after enrollment

  8. Mean Near Control at 3 Years

    Mean exotropia control at near was assessed in all patients who completed the 3-year visit. All 3-year visit data will be analyzed regardless of what treatment(s) a patient has received and regardless of whether the patient has undergone reoperation. Control at near was analyzed as a continuous variable and compared between treatment groups using analysis of covariance (ANOVA) models that adjust for the corresponding baseline value (e.g. ANCOVA model of 3-year near control will adjust for baseline near control). Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

    Time frame: 3 years after enrollment

  9. Change in Near Exotropia Control at 3 Years

    Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement. Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

    Time frame: Enrollment to 3 Years

  10. Number of Participants With Distance PACT at 3 Years

    The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. PACT was assessed in all patients who completed the 3-year visit. ∆ = prism diopters; eso = esodeviation; exo = exodeviation

    Time frame: 3 years after enrollment

  11. Mean Distance PACT at 3 Years

    The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. Mean PACT was assessed in all patients who completed the 3-year visit. All 3-year visit data will be analyzed regardless of what treatment(s) a patient has received and regardless of whether the patient has undergone reoperation. PACT was analyzed as a continuous variable and compared between treatment groups using analysis of covariance (ANOVA) models that adjust for the corresponding baseline value (e.g. ANCOVA model of 3-year PACT at distance will adjust for baseline PACT at distance).

    Time frame: 3 years after enrollment

  12. Change in Distance PACT From Baseline to 3 Years

    The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement. If the 3-year PACT is an esodeviation, change in PACT from baseline is the reduction in the exodeviation plus the amount of the 3-year exodeviation.

    Time frame: Enrollment to 3 years

  13. Number of Participants With Near PACT at 3 Years

    The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. PACT was assessed in all patients who completed the 3-year visit. ∆ = prism diopters; eso = esodeviation; exo = exodeviation

    Time frame: 3 years after enrollment

  14. Mean Near PACT at 3 Years

    The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. Mean PACT was assessed in all patients who completed the 3-year visit. All 3-year visit data will be analyzed regardless of what treatment(s) a patient has received and regardless of whether the patient has undergone reoperation. PACT was analyzed as a continuous variable and compared between treatment groups using analysis of covariance (ANOVA) models that adjust for the corresponding baseline value (e.g. ANCOVA model of 3-year PACT at near will adjust for baseline PACT at near).

    Time frame: 3 years after enrollment

  15. Change in Near PACT From Baseline to 3 Years

    The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement. If the 3-year PACT is an esodeviation, change in PACT from baseline is the reduction in the exodeviation plus the amount of the 3-year exodeviation.

    Time frame: Enrollment to 3 years

  16. Participants With Near Stereoacuity Measures at 3 Years

    Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. Stereoacuity Testing: stereoacuity was assessed in current refractive correction using the following: Preschool Randot stereotest at near (performed at 40 cm): If stereoacuity is worse than 40 arcsec, it must be retested and the better of the 2 measurements will be used for eligibility. Distance Randot stereotest (performed at 3 meters)

    Time frame: 3 years after enrollment

  17. Mean Near Stereoacuity at 3 Years

    Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. A logarithm base 10 transformation was used to convert stereoacuity scores to the log scale to calculate descriptive statistics (reported as seconds of arc, or arcsec). Stereoacuity Testing: stereoacuity was assessed in current refractive correction using the following: Preschool Randot stereotest at near (performed at 40 cm): If stereoacuity is worse than 40 arcsec, it must be retested and the better of the 2 measurements will be used for eligibility. Distance Randot stereotest (performed at 3 meters)

    Time frame: 3 years after enrollment

  18. Change in Near Stereoacuity From Baseline to 3 Years

    Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. A logarithm base 10 transformation was used to convert stereoacuity scores to the log scale to calculate descriptive statistics (reported as seconds of arc, or arcsec). Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement.

    Time frame: Enrollment to 3 years

  19. Participants Distance Stereoacuity at 3 Years

    Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. Stereoacuity Testing: stereoacuity was assessed in current refractive correction using the following: Preschool Randot stereotest at near (performed at 40 cm): If stereoacuity is worse than 40 arcsec, it must be retested and the better of the 2 measurements will be used for eligibility. Distance Randot stereotest (performed at 3 meters)

    Time frame: 3 years after enrollment

  20. Mean Distance Stereoacuity at 3 Years

    Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. A logarithm base 10 transformation was used to convert stereoacuity scores to the log scale to calculate descriptive statistics (reported as seconds of arc, or arcsec). Stereoacuity Testing: stereoacuity was assessed in current refractive correction using the following: Preschool Randot stereotest at near (performed at 40 cm): If stereoacuity is worse than 40 arcsec, it must be retested and the better of the 2 measurements will be used for eligibility. Distance Randot stereotest (performed at 3 meters)

    Time frame: 3 years after enrollment

  21. Change in Distance Stereoacuity From Baseline to 3 Years

    Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. A logarithm base 10 transformation was used to convert stereoacuity scores to the log scale to calculate descriptive statistics (reported as seconds of arc, or arcsec). Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement.

    Time frame: Enrollment to 3 years

  22. Health Related Quality of Life

    Health-related quality of life will be assessed using the Intermittent Exotropia Questionnaire (IXTQ). This questionnaire consists of 6 components: 1. Child questionnaire - consists of 12 items which assess how the child feels about his/her eye condition. * One version for children aged 5 to \< 8 years has a 3-level response scale * The version for children aged 8 years and older has a 5-level response scale 2. Parent proxy questionnaire - consists of 12 items which assess how the parent feels the child's eye condition affects the child 3. Parental questionnaire - consists of 17 items which assess how the child's eye condition affects the parent. Has 3 sub-scales: surgical, functional, and psycho-social. All scales ranged from 0 to 100; higher values indicated a better quality of life. Sub-scales were not combined, but rather were each evaluated individually on a scale of 0-100.

    Time frame: 3 years after enrollment

  23. Cumulative Number of Patients With Reoperation by 3 Years

    The cumulative proportion of re-operation by 3 years was compared between treatment groups using methods similar to the primary analysis (i.e. using Kaplan-Meier method). A treatment-group difference and a corresponding 95% confidence interval were also calculated. Reasons for re-operation included: XT; XT and worsening stereo ; XT, worsening stereo and social concerns ; XT, diplopia, and headaches ; XT and squinting with one eye closed ; ET ; ET, worsening stereo, and diplopia; ET, worsening stereo and social concerns ; ET, worsening stereo, social concerns, and amblyopia ; Inferior oblique overaction

    Time frame: 3 years after enrollment

  24. Number of Participants With Complete or Near-Complete Resolution at 3 Years

    Complete or near-complete resolution was defined as meeting all of the following at the 3 year visit: 1) exodeviation \<10 Δ (tropia or phoria) by both SPCT and PACT at distance and near and ≥10 Δ reduction in PACT magnitude from the largest of the distance and near angles at enrollment, 2) esotropia \<6 Δ at distance and near by SPCT, 3) no decrease in Randot Preschool stereoacuity of ≥2 octaves from the enrollment stereoacuity or to nil, 4) no reoperation or treatment with botulinum toxin, and 5) no non-surgical treatment for a recurrent or residual exodeviation.

    Time frame: 3 years after enrollment

  25. Participants Suboptimal Surgical Outcome at 3 Years

    Suboptimal surgical outcome at the 3-year visit was defined as meeting any of the three suboptimal surgical outcome criteria at the 3-year visit (regardless of whether the criterion had been met at an earlier visit), or undergoing reoperation at any time. The three criteria for suboptimal surgical outcome were: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest

    Time frame: 3 years after enrollment

07

Results

Posted May 7, 2019

Participant flow

Participant flow — Overall Study
MilestoneBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Started10196
Completed8677
Not completed1519

Outcome measures

PrimaryNumber of Participants With Suboptimal Surgical Outcome as Assessed by Motor Alignment and Stereoacuity at Near by 3 Years

A participant's intermittent exotropia (IXT) was considered to be a suboptimal surgical outcome if at any visit occurring 6 months or later, ANY of the following criteria are present by masked examiner testing: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest Participants who underwent reoperation (or treatment with botulinum toxin) without first meeting any of the above suboptimal surgical outcome criteria were also counted as suboptimal surgical outcomes in the primary analysis.

Time frame:
3 years
Reported as:
Count of participants · Participants
Number of Participants With Suboptimal Surgical Outcome as Assessed by Motor Alignment and Stereoacuity at Near by 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Number of Participants With Suboptimal Surgical Outcome as Assessed by Motor Alignment and Stereoacuity at Near by 3 Years4333
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Z test · p = 0.24 · Difference in percentage of participants: 9 · 95% CI -6 to 23Proportion of participants meeting criteria was obtained by Kaplan-Meier method. BLR group=46%, RR group=37%. Probability was compared b/w groups using Z test. A group difference and 95% CI were calculated. Positive differences favor the RR group.
SecondaryPatients With Exotropia by 3 Years

Exotropia ≥10Δ by simultaneous prism and cover test (SPCT) at distance or near, confirmed by a retest, by 3 years. Criteria was met before any reoperation, and regardless of whether suboptimal surgical outcome was met by another criteria.

Time frame:
Enrollment to 3 years
Reported as:
Count of participants · Participants
Patients With Exotropia by 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Patients With Exotropia by 3 Years3122
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Z test · p = 0.25 · Difference in percentage of participants: 8 · 95% CI -6 to 21Proportion of participants meeting criteria was obtained by Kaplan-Meier method. BLR group=34%, RR group=26%. Probability was compared b/w groups using Z test. A group difference and 95% CI were calculated. Positive differences favor the RR group.
SecondaryPatients With Constant Esotropia by 3 Years

Constant esotropia ≥6Δ by simultaneous prism and cover test (SPCT) at distance or near, confirmed by a retest, by 3 years. Criteria was met before any reoperation, and regardless of whether suboptimal surgical outcome was met by another criteria.

Time frame:
Enrollment to 3 years
Reported as:
Count of participants · Participants
Patients With Constant Esotropia by 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Patients With Constant Esotropia by 3 Years39
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Z test · p = 0.06 · Difference in percentage of participants: -7 · 95% CI -14 to 0.23Proportion of participants meeting criteria was obtained by Kaplan-Meier method. BLR group=3%, RR group=10%. Probability was compared b/w groups using Z test. A group difference and 95% CI were calculated. Positive differences favor the RR group.
SecondaryNumber of Participants With Stereo Loss by 3 Years

Decrease in Preschool Randot near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest, by 3 years. Criteria was met before any reoperation, and regardless of whether suboptimal surgical outcome was met by another criteria.

Time frame:
Enrollment to 3 years
Reported as:
Count of participants · Participants
Number of Participants With Stereo Loss by 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Number of Participants With Stereo Loss by 3 Years139
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Z test · p = 0.36 · Difference in percentage of participants: 4 · 95% CI -5 to 14Proportion of participants meeting criteria by 3 yrs was obtained by KM method. BLR group=14%, RR group=10%. Probability was compared b/w groups using Z test. A group difference and 95% CI were calculated. Positive differences favor the RR group.
SecondaryNumber of Participants With Exotropia Control at Distance at 3 Years

Exotropia control at distance was assessed in all patients who completed the 3-year visit. Numeric values for exotropia control were assigned so that the following seven categories were created: Not applicable (no exodeviation) (0) No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Number of Participants With Exotropia Control at Distance at 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Not applicable (no exodeviation)1925
(0) No exotropia unless dissociated, recovers <1 s2522
(1) No exotropia unless dissociated, recovers 1-51411
(2) No exotropia unless dissociated, recovers >5 s126
(3) Exotropia <50% of 30-second observation54
(4) Exotropia >50% of 30-second observation64
(5) Constant exotropia55
SecondaryMean Distance Control at 3 Years

Mean exotropia control at distance was assessed in all patients who completed the 3-year visit. All 3-year visit data will be analyzed regardless of what treatment(s) a patient has received and regardless of whether the patient has undergone reoperation. Control at distance was analyzed as a continuous variable and compared between treatment groups using analysis of covariance (ANOVA) models that adjust for the corresponding baseline value (e.g. ANCOVA model of 3-year distance control will adjust for baseline distance control). Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

Time frame:
3 years after enrollment
Reported as:
Mean · score on a scale
Mean Distance Control at 3 Years
score on a scaleBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Mean Distance Control at 3 Years1.2 ± 1.61.0 ± 1.6
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · ANOVA · p = 0.44
SecondaryChange in Distance Exotropia Control at 3 Years

Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement. Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

Time frame:
Enrollment to 3 years
Reported as:
Mean · score on a scale
Change in Distance Exotropia Control at 3 Years
score on a scaleBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Change in Distance Exotropia Control at 3 Years2.3 ± 1.72.5 ± 1.7
SecondaryNumber of Participants With Exotropia Control at Near at 3 Years

Exotropia control at near was assessed in all patients who completed the 3-year visit. Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Number of Participants With Exotropia Control at Near at 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Not applicable (no exodeviation)2021
(0) No exotropia unless dissociated, recovers <1 s3632
(1) No exotropia unless dissociated, recovers 1-51613
(2) No exotropia unless dissociated, recovers >5 s64
(3) Exotropia <50% of 30-second observation14
(4) Exotropia >50% of 30-second observation63
(5) Constant exotropia10
SecondaryMean Near Control at 3 Years

Mean exotropia control at near was assessed in all patients who completed the 3-year visit. All 3-year visit data will be analyzed regardless of what treatment(s) a patient has received and regardless of whether the patient has undergone reoperation. Control at near was analyzed as a continuous variable and compared between treatment groups using analysis of covariance (ANOVA) models that adjust for the corresponding baseline value (e.g. ANCOVA model of 3-year near control will adjust for baseline near control). Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

Time frame:
3 years after enrollment
Reported as:
Mean · score on a scale
Mean Near Control at 3 Years
score on a scaleBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Mean Near Control at 3 Years0.7 ± 1.20.6 ± 1.1
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · ANOVA · p = 0.64
SecondaryChange in Near Exotropia Control at 3 Years

Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement. Numeric values for exotropia control were assigned so that the following categories were created: Not applicable (no exodeviation) 0: No exotropia unless dissociated, recovers \<1 secs (phoria) 1. No exotropia unless dissociated, recovers 1-5 secs 2. No exotropia unless dissociated, recovers \>5 secs 3. Exotropia \<50% of 30-second observation 4. Exotropia \>50% of 30-second observation 5. Constant exotropia Lower scores indicate better control.

Time frame:
Enrollment to 3 Years
Reported as:
Mean · score on a scale
Change in Near Exotropia Control at 3 Years
score on a scaleBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Change in Near Exotropia Control at 3 Years1.3 ± 1.61.1 ± 1.6
SecondaryNumber of Participants With Distance PACT at 3 Years

The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. PACT was assessed in all patients who completed the 3-year visit. ∆ = prism diopters; eso = esodeviation; exo = exodeviation

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Number of Participants With Distance PACT at 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
No Deviation1021
1-9∆ Exo2317
10-14∆ Exo1512
15-18∆ Exo107
20-25∆ Exo1612
30-35∆ Exo32
40-45∆ Exo00
10-14∆ Eso20
1-9∆ Eso76
SecondaryMean Distance PACT at 3 Years

The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. Mean PACT was assessed in all patients who completed the 3-year visit. All 3-year visit data will be analyzed regardless of what treatment(s) a patient has received and regardless of whether the patient has undergone reoperation. PACT was analyzed as a continuous variable and compared between treatment groups using analysis of covariance (ANOVA) models that adjust for the corresponding baseline value (e.g. ANCOVA model of 3-year PACT at distance will adjust for baseline PACT at distance).

Time frame:
3 years after enrollment
Reported as:
Mean · prism diopters
Mean Distance PACT at 3 Years
prism dioptersBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Mean Distance PACT at 3 Years10 ± 109 ± 10
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · ANOVA · p = 0.21
SecondaryChange in Distance PACT From Baseline to 3 Years

The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement. If the 3-year PACT is an esodeviation, change in PACT from baseline is the reduction in the exodeviation plus the amount of the 3-year exodeviation.

Time frame:
Enrollment to 3 years
Reported as:
Mean · prism diopters
Change in Distance PACT From Baseline to 3 Years
prism dioptersBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Change in Distance PACT From Baseline to 3 Years16 ± 1118 ± 10
SecondaryNumber of Participants With Near PACT at 3 Years

The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. PACT was assessed in all patients who completed the 3-year visit. ∆ = prism diopters; eso = esodeviation; exo = exodeviation

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Number of Participants With Near PACT at 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
No Deviation1115
1-9∆ Exo2124
10-14∆ Exo169
15-18∆ Exo115
20-25∆ Exo1314
30-35∆ Exo33
40-45∆ Exo10
10-14∆ Eso10
1-9∆ Eso97
SecondaryMean Near PACT at 3 Years

The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. Mean PACT was assessed in all patients who completed the 3-year visit. All 3-year visit data will be analyzed regardless of what treatment(s) a patient has received and regardless of whether the patient has undergone reoperation. PACT was analyzed as a continuous variable and compared between treatment groups using analysis of covariance (ANOVA) models that adjust for the corresponding baseline value (e.g. ANCOVA model of 3-year PACT at near will adjust for baseline PACT at near).

Time frame:
3 years after enrollment
Reported as:
Mean · prism diopters
Mean Near PACT at 3 Years
prism dioptersBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Mean Near PACT at 3 Years10 ± 119 ± 10
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · ANOVA · p = 0.38
SecondaryChange in Near PACT From Baseline to 3 Years

The prism and alternate cover test (PACT) is used to measure the angle of strabismus, or deviation, in prism diopters. This is measured separately at distance and at near. Smaller numbers are better because they indicate a smaller angle of deviation. Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement. If the 3-year PACT is an esodeviation, change in PACT from baseline is the reduction in the exodeviation plus the amount of the 3-year exodeviation.

Time frame:
Enrollment to 3 years
Reported as:
Mean · prism diopters
Change in Near PACT From Baseline to 3 Years
prism dioptersBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Change in Near PACT From Baseline to 3 Years15 ± 1216 ± 12
SecondaryParticipants With Near Stereoacuity Measures at 3 Years

Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. Stereoacuity Testing: stereoacuity was assessed in current refractive correction using the following: Preschool Randot stereotest at near (performed at 40 cm): If stereoacuity is worse than 40 arcsec, it must be retested and the better of the 2 measurements will be used for eligibility. Distance Randot stereotest (performed at 3 meters)

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Participants With Near Stereoacuity Measures at 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
403437
602317
1001912
20034
40044
80011
Nil22
SecondaryMean Near Stereoacuity at 3 Years

Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. A logarithm base 10 transformation was used to convert stereoacuity scores to the log scale to calculate descriptive statistics (reported as seconds of arc, or arcsec). Stereoacuity Testing: stereoacuity was assessed in current refractive correction using the following: Preschool Randot stereotest at near (performed at 40 cm): If stereoacuity is worse than 40 arcsec, it must be retested and the better of the 2 measurements will be used for eligibility. Distance Randot stereotest (performed at 3 meters)

Time frame:
3 years after enrollment
Reported as:
Mean · logarithm of seconds of arc (log arcsec)
Mean Near Stereoacuity at 3 Years
logarithm of seconds of arc (log arcsec)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Mean Near Stereoacuity at 3 Years1.9 ± 0.31.8 ± 0.4
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · ANOVA · p = 0.93
SecondaryChange in Near Stereoacuity From Baseline to 3 Years

Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. A logarithm base 10 transformation was used to convert stereoacuity scores to the log scale to calculate descriptive statistics (reported as seconds of arc, or arcsec). Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement.

Time frame:
Enrollment to 3 years
Reported as:
Mean · logarithm of seconds of arc (log arcsec)
Change in Near Stereoacuity From Baseline to 3 Years
logarithm of seconds of arc (log arcsec)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Change in Near Stereoacuity From Baseline to 3 Years0.2 ± 0.40.2 ± 0.4
SecondaryParticipants Distance Stereoacuity at 3 Years

Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. Stereoacuity Testing: stereoacuity was assessed in current refractive correction using the following: Preschool Randot stereotest at near (performed at 40 cm): If stereoacuity is worse than 40 arcsec, it must be retested and the better of the 2 measurements will be used for eligibility. Distance Randot stereotest (performed at 3 meters)

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Participants Distance Stereoacuity at 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
603035
100177
2002014
400710
Nil1210
Missing01
SecondaryMean Distance Stereoacuity at 3 Years

Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. A logarithm base 10 transformation was used to convert stereoacuity scores to the log scale to calculate descriptive statistics (reported as seconds of arc, or arcsec). Stereoacuity Testing: stereoacuity was assessed in current refractive correction using the following: Preschool Randot stereotest at near (performed at 40 cm): If stereoacuity is worse than 40 arcsec, it must be retested and the better of the 2 measurements will be used for eligibility. Distance Randot stereotest (performed at 3 meters)

Time frame:
3 years after enrollment
Reported as:
Mean · logarithm of seconds of arc (log arcsec
Mean Distance Stereoacuity at 3 Years
logarithm of seconds of arc (log arcsecBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Mean Distance Stereoacuity at 3 Years2.2 ± 0.42.2 ± 0.4
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · ANOVA · p = 0.82
SecondaryChange in Distance Stereoacuity From Baseline to 3 Years

Stereoacuity scores (seconds of arc) were calculated based on the Randot Preschool stereoacuity test (scores: 800, 400, 200, 100, 60 and 40). Seconds of arc refers to the visual angle that is being measured in order to determine depth perception. Lower scores indicate better stereoacuity. A logarithm base 10 transformation was used to convert stereoacuity scores to the log scale to calculate descriptive statistics (reported as seconds of arc, or arcsec). Change is defined as the baseline value minus the 3-year value, therefore positive change = improvement.

Time frame:
Enrollment to 3 years
Reported as:
Mean · logarithm of seconds of arc (log arcsec)
Change in Distance Stereoacuity From Baseline to 3 Years
logarithm of seconds of arc (log arcsec)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Change in Distance Stereoacuity From Baseline to 3 Years0.1 ± 0.40.1 ± 0.4
SecondaryHealth Related Quality of Life

Health-related quality of life will be assessed using the Intermittent Exotropia Questionnaire (IXTQ). This questionnaire consists of 6 components: 1. Child questionnaire - consists of 12 items which assess how the child feels about his/her eye condition. * One version for children aged 5 to \< 8 years has a 3-level response scale * The version for children aged 8 years and older has a 5-level response scale 2. Parent proxy questionnaire - consists of 12 items which assess how the parent feels the child's eye condition affects the child 3. Parental questionnaire - consists of 17 items which assess how the child's eye condition affects the parent. Has 3 sub-scales: surgical, functional, and psycho-social. All scales ranged from 0 to 100; higher values indicated a better quality of life. Sub-scales were not combined, but rather were each evaluated individually on a scale of 0-100.

Time frame:
3 years after enrollment
Reported as:
Median · score on a scale
Health Related Quality of Life
score on a scaleBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Child 5 to 7 years old IXTQ91 (0 to 100)86 (0 to 100)
Child 8 to 13 years old IXTQ82 (0 to 100)82 (0 to 100)
Parent Proxy IXTQ86 (0 to 100)91 (0 to 100)
Parent Psychosocial97 (0 to 100)100 (0 to 100)
Parent Function83 (0 to 100)86 (0 to 100)
Parent Surgery83 (0 to 100)92 (0 to 100)
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Wilcoxon (Mann-Whitney) · p = 0.30 (Child 5 to 7 years old)
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Wilcoxon (Mann-Whitney) · p = 0.77 (Child 8 to 13 years old)
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Wilcoxon (Mann-Whitney) · p = 0.51 (Parent Proxy IXTQ)
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Wilcoxon (Mann-Whitney) · p = 0.42 (Parent Psychosocial)
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Wilcoxon (Mann-Whitney) · p = 0.68 (Parent Function)
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Wilcoxon (Mann-Whitney) · p = 0.64 (Parent Surgical)
SecondaryCumulative Number of Patients With Reoperation by 3 Years

The cumulative proportion of re-operation by 3 years was compared between treatment groups using methods similar to the primary analysis (i.e. using Kaplan-Meier method). A treatment-group difference and a corresponding 95% confidence interval were also calculated. Reasons for re-operation included: XT; XT and worsening stereo ; XT, worsening stereo and social concerns ; XT, diplopia, and headaches ; XT and squinting with one eye closed ; ET ; ET, worsening stereo, and diplopia; ET, worsening stereo and social concerns ; ET, worsening stereo, social concerns, and amblyopia ; Inferior oblique overaction

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Cumulative Number of Patients With Reoperation by 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Cumulative Number of Patients With Reoperation by 3 Years94
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Difference in percentage: 5 · 95% CI -2 to 13
SecondaryNumber of Participants With Complete or Near-Complete Resolution at 3 Years

Complete or near-complete resolution was defined as meeting all of the following at the 3 year visit: 1) exodeviation \<10 Δ (tropia or phoria) by both SPCT and PACT at distance and near and ≥10 Δ reduction in PACT magnitude from the largest of the distance and near angles at enrollment, 2) esotropia \<6 Δ at distance and near by SPCT, 3) no decrease in Randot Preschool stereoacuity of ≥2 octaves from the enrollment stereoacuity or to nil, 4) no reoperation or treatment with botulinum toxin, and 5) no non-surgical treatment for a recurrent or residual exodeviation.

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Number of Participants With Complete or Near-Complete Resolution at 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Number of Participants With Complete or Near-Complete Resolution at 3 Years2635
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Difference in percentage of participants: -15 · 95% CI -30 to -.0003
SecondaryParticipants Suboptimal Surgical Outcome at 3 Years

Suboptimal surgical outcome at the 3-year visit was defined as meeting any of the three suboptimal surgical outcome criteria at the 3-year visit (regardless of whether the criterion had been met at an earlier visit), or undergoing reoperation at any time. The three criteria for suboptimal surgical outcome were: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest

Time frame:
3 years after enrollment
Reported as:
Count of participants · Participants
Participants Suboptimal Surgical Outcome at 3 Years
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Participants Suboptimal Surgical Outcome at 3 Years2513
Statistical analysis
  • Bilateral Lateral Rectus Recession vs Unilateral Lateral Rectus Recession · Difference in percentage of participants: 12 · 95% CI -1 to 25
PrimaryPrimary Outcome Measure Stratified by Sex

NIH-required analysis. Primary OM (stratified by sex): A participant's intermittent exotropia (IXT) was considered to be a suboptimal surgical outcome if at any visit occurring 6 months or later, ANY of the following criteria are present by masked examiner testing: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest Participants who underwent reoperation (or treatment with botulinum toxin) without first meeting any of the above suboptimal surgical outcome criteria were also counted as suboptimal surgical outcomes in the primary analysis

Time frame:
3 years
Reported as:
Count of participants · Participants
Primary Outcome Measure Stratified by Sex
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Female2922
Male1411
PrimaryPrimary Outcome Measure Stratified by Race

NIH-required analysis. Primary OM stratified by race: A participant's intermittent exotropia (IXT) was considered to be a suboptimal surgical outcome if at any visit occurring 6 months or later, ANY of the following criteria are present by masked examiner testing: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest Participants who underwent reoperation (or treatment with botulinum toxin) without first meeting any of the above suboptimal surgical outcome criteria were also counted as suboptimal surgical outcomes in the primary analysis

Time frame:
3 years
Reported as:
Count of participants · Participants
Primary Outcome Measure Stratified by Race
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
American Indian/Alaskan Native12
Asian2—
Black/African American84
More than one race22
Native Hawaiian/Other Pacific Islander—0
Unknown/Not Reported31
White2724
PrimaryPrimary Outcome Measure Stratified by Ethnicity

NIH-required analysis. POM stratified by ethnicity: A participant's intermittent exotropia (IXT) was considered to be a suboptimal surgical outcome if at any visit occurring 6 months or later, ANY of the following criteria are present by masked examiner testing: 1. Exotropia at distance OR near at any time during the exam (i.e., can be constant or intermittent; determined by a cover/uncover test) with a magnitude of ≥10Δ by SPCT, confirmed by a retest 2. Constant esotropia at distance OR near (determined by at least 3 cover/uncover tests-one must be before any dissociation) with a magnitude of ≥6Δ by SPCT, confirmed by a retest 3. Decrease in Randot Preschool near stereoacuity ≥2 octaves (≥0.6 log arcsec) from enrollment, or to nil, confirmed by a retest Participants who underwent reoperation (or treatment with botulinum toxin) without first meeting any of the above suboptimal surgical outcome criteria were also counted as suboptimal surgical outcomes in the primary analysis

Time frame:
3 years
Reported as:
Count of participants · Participants
Primary Outcome Measure Stratified by Ethnicity
ParticipantsBilateral Lateral Rectus RecessionUnilateral Lateral Rectus Recession
Hispanic or Latino68
Not Hispanic or Latino3625
Unknown/Not Reported1—

Adverse events

Collected over 3 years. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Bilateral Lateral Rectus Recession0/101 (0%)0/101 (0%)0/101 (0%)
Unilateral Lateral Rectus Recession0/96 (0%)0/96 (0%)0/96 (0%)

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus RecessionTotal
<=18 years10196197
Between 18 and 65 years000
>=65 years000
Age, Continuous
Age, Continuous(Years)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus RecessionTotal
Mean6.4 ± 2.15.9 ± 1.96.2 ± 2.0
Age, Customized
Age, Customized(Participants)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus RecessionTotal
3 to <4 years old141529
4 to <5 years old192443
5 to <6 years old142034
6 to <7 years old151025
7 to <8 years old151126
8 to <9 years old10414
9 to <10 years old91019
10 to <11 years old527
Sex: Female, Male
Sex: Female, Male(Participants)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus RecessionTotal
Female6458122
Male373875
Race/Ethnicity, Customized
Race/Ethnicity, Customized(Participants)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus RecessionTotal
White5855113
African American131427
Hispanic192544
Other11213
Prior Nonsurgical Treatment
Prior Nonsurgical Treatment(Participants)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus RecessionTotal
No treatment494998
Patching alone362965
Overminus spectacles alone6410
Vision therapy alone235
Combination or other81119
Randot Preschool Stereoacuity
Randot Preschool Stereoacuity(Participants)Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus RecessionTotal
40 Arcsec151631
60 Arcsec222042
100 Arcsec283159
200 Arcsec121325
400 Arcsec241640
Randot Preschool Stereoacuity (log arcsec)
Randot Preschool Stereoacuity (log arcsec)(logarithm of seconds of arc (log arcsec))Bilateral Lateral Rectus RecessionUnilateral Lateral Rectus RecessionTotal
Mean2.1 ± 0.42.0 ± 0.32.1 ± 0.3

8 further baseline measures are reported on the registry.

08

Study locations

1 site
  • Vanderbilt Children's Hospital
    Nashville, Tennessee 37232-8808, United States
09

References and documents

Publications

  • Repka MX, Chandler DL, Holmes JM, Donahue SP, Hoover DL, Mohney BG, Phillips PH, Stout AU, Ticho BH, Wallace DK; Pediatric Eye Disease Investigator Group. The Relationship of Age and Other Baseline Factors to Outcome of Initial Surgery for Intermittent Exotropia. Am J Ophthalmol. 2020 Apr;212:153-161. doi: 10.1016/j.ajo.2019.12.008. Epub 2019 Dec 17. PubMed 31862447 ↗
  • Pediatric Eye Disease Investigator Group; Writing Committee; Donahue SP, Chandler DL, Holmes JM, Arthur BW, Paysse EA, Wallace DK, Petersen DB, Melia BM, Kraker RT, Miller AM. A Randomized Trial Comparing Bilateral Lateral Rectus Recession versus Unilateral Recess and Resect for Basic-Type Intermittent Exotropia. Ophthalmology. 2019 Feb;126(2):305-317. doi: 10.1016/j.ophtha.2018.08.034. Epub 2018 Sep 3. PubMed 30189281 ↗
  • Holmes JM, Hercinovic A, Melia BM, Leske DA, Hatt SR, Chandler DL, Dean TW, Kraker RT, Enyedi LB, Wallace DK, Donahue SP, Cotter SA; Pediatric Eye Disease Investigator Group. Improvement in health-related quality of life following strabismus surgery for children with intermittent exotropia. J AAPOS. 2021 Apr;25(2):82.e1-82.e7. doi: 10.1016/j.jaapos.2020.11.021. Epub 2021 Apr 24. PubMed 33905836 ↗
  • Donahue SP, Chandler DL, Wu R, Marsh JD, Law C, Areaux RG Jr, Ghasia FF, Li Z, Kraker RT, Cotter SA, Holmes JM; Pediatric Eye Disease Investigator Group. Eight-Year Outcomes of Bilateral Lateral Rectus Recessions versus Unilateral Recession-Resection in Childhood Basic-Type Intermittent Exotropia. Ophthalmology. 2024 Jan;131(1):98-106. doi: 10.1016/j.ophtha.2023.09.004. Epub 2023 Sep 9. PubMed 37696452 ↗
  • Pang Y, Gnanaraj L, Gayleard J, Han G, Hatt SR. Interventions for intermittent exotropia. Cochrane Database Syst Rev. 2021 Sep 13;9(9):CD003737. doi: 10.1002/14651858.CD003737.pub4. PubMed 34516656 ↗

Study documents

PDFs hosted by the registry, ClinicalTrials.gov.

Individual participant data

Plan to share: Yes — In accordance with the NIH data sharing policy, a de-identified database is placed in the public domain on the PEDIG public website after the completion of each protocol and publication of the primary manuscript.

Time frame: Data will be made available after publication of each primary manuscript.

Access criteria: Users accessing the data must enter an email address.

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 9, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT01032603
Collaborators
Pediatric Eye Disease Investigator Group, National Eye Institute (NEI)
Responsible party
Sponsor
First posted
Dec 15, 2009
Start date
Jun 1, 2010
Primary completion
Feb 9, 2017
Completion
Feb 18, 2022
Results posted
May 7, 2019
Last update
Jul 9, 2026

Study contacts

Sean P Donahue, M.D., Ph.D.
study chair · Pediatric Ophthalmology Service, Vanderbilt Children's Hospital, Nashville, TN

Oversight

Data monitoring committee
Yes
View the source record on ClinicalTrials.gov ↗

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