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Clinical Trials/NCT03998670
NCT03998670CompletedNot Applicable

Intermittent Exotropia Study 6: A Pilot Randomized Clinical Trial of Base-in Prism Spectacles for Intermittent Exotropia

Jaeb Center for Health Research56 sites in 1 country61 target enrollmentStarted: September 1, 2019Last updated:
Conditions

Trial Snapshot

Phase
Not Applicable
Status
Completed
Sponsor
Enrollment
61
Locations
56
Primary Endpoint
Exotropia Control Score at Distance, Continuous Score

Study Overview

Brief Summary

The objective of this short-term, pilot randomized trial comparing spectacles with relieving prism to spectacles without prism is to determine whether to proceed to a full-scale, longer-term randomized trial. This decision will be based primarily on assessing the initial (8-week) response to prism by comparing treatment groups on the following outcomes:

  • Mean distance intermittent exotropia (IXT) control score (the mean of 3 control scores) (primary outcome)
  • The proportion of participants demonstrating a "treatment response," defined as ≥1 point improvement in the mean distance IXT control score without spontaneous exotropia during control testing (secondary outcome)
  • The proportion of participants reporting adverse effects and good/excellent spectacle wear compliance

Study Design

Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel
Primary Purpose
Treatment
Masking
Single (Outcomes Assessor)

Masking Description

At the 8-week outcome visit, a Masked Examiner, who is a pediatric ophthalmologist, pediatric optometrist, or certified orthoptist, will assess the control of the exodeviation and perform PACT testing. The Masked Examiner must be someone other than the investigator.

Eligibility Criteria

Ages
3 Years to 13 Years (Child)
Sex
All
Accepts Healthy Volunteers
No

Inclusion Criteria

  • Intermittent Exotropia meeting all of the following criteria:
  • Age 3 to 13 years
  • Mean distance control score of ≥2.00 points with at least 1 measure of 3, 4, or 5 points (i.e, spontaneous tropia) from the 3 assessments during the exam
  • A near control score ≤4 on at least 1 of 3 assessments (cannot have score of 5, 5, 5)
  • Distance exodeviation between 16 Prism Diopters (Δ) and 35 Δ (inclusive) by PACT
  • Near exodeviation between 10 Δ and 35 Δ (inclusive) by PACT
  • Near deviation does not exceed distance deviation by more than 10 Δ by PACT (i.e., convergence insufficiency-type IXT excluded)
  • Refractive error between -6.00 Diopters (D) spherical equivalent (SE) and +2.50 D SE (inclusive) (based on a cycloplegic refraction performed within 7 months but prior to the day of enrollment)
  • Refractive correction (must be worn for at least 1 week if refractive error meets any of the following (based on a cycloplegic refraction performed within 7 months but prior to the day of enrollment):
  • SE anisometropia ≥1.00 D
  • Astigmatism ≥1.00 D in either eye
  • SE myopia ≥-0.50 D in either eye
  • If spectacles have been prescribed and are worn, they must meet the following pre- enrollment criteria:
  • SE anisometropia corrected to within 1.00 D of full SE anisometropic difference
  • Astigmatism corrected to within 1.00 D of full magnitude; axis within 10 degrees if astigmatism ≤1.00 D and axis within 5 degrees if astigmatism >1.00 D

Exclusion Criteria

  • Dissociated vertical deviation (DVD)
  • Vertical deviation >3 Δ in primary gaze at distance or near
  • Patterns (such as an "A" or "V" pattern) with a downgaze measurement of >10 Δ difference from straight ahead by PACT, measured per investigator's routine method
  • Treatment for IXT or amblyopia (other than refractive correction) within the past 4 weeks, including vision therapy, orthoptics, patching, atropine, or other penalization
  • Substantial overminus spectacles (spectacles overminused by more than 1.00 D SE than the most recent cycloplegic refraction and also results in minus SE power in the spectacles; underplussing is allowed) within the past 4 weeks
  • Prior strabismus, intraocular, or refractive surgery (including BOTOX injection)
  • Previous use of prism spectacles
  • Additional Eligibility Criteria for Randomization Based on Prism Adaptation Testing
  • Exodeviation by PACT while wearing "trial" relieving prism for 30 minutes is smaller at distance or near than measured during initial testing (e.g. not fully adapting to prism at both distances)
  • No new esotropia on cover test at near while wearing "trial" relieving prism for 30 minutes, compared with enrollment measurement taken without prism
  • No esodeviation >6 Δ on PACT at near while wearing "trial" relieving prism for 30 minutes

Outcomes

Primary Outcomes

Exotropia Control Score at Distance, Continuous Score

Time Frame: 8 weeks

The primary analysis will be an intent-to-treat comparison of mean 8-week control of the distance exodeviation (average of 3 measurements) between treatment groups using an analysis of covariance (ANCOVA) model, which adjusts for baseline distance control. Distance control scores range from 0 to 5 with higher scores indicating a worse outcome.

Secondary Outcomes

  • Exotropia Control Score at Distance, % With Treatment Response(8 weeks)
  • Exodeviation by PACT at Distance, Continuous(8 Weeks)
  • Exodeviation by PACT at Near, Continuous(8 Weeks)
  • Exotropia Control Score at Distance and Near, % With No Spontaneous Tropia(8 Weeks)
  • Exotropia Control Score at Distance, Continuous Change Between Baseline and 8 Weeks(8 Weeks)
  • Child Assessment of Symptoms - Do Your Eyes Hurt?(8 Weeks)
  • Child Assessment of Symptoms - Do You Have Double Vision?(8 Weeks)
  • Parent Assessment of Symptoms and Spectacle Wear - Has Your Child Had Headaches?(8 Weeks)
  • Parent Assessment of Symptoms and Spectacle Wear - Has Your Child Avoided Reading or Doing Things up Close?(8 Weeks)
  • Exotropia Control Score at Near, Continuous Score(8 Weeks)
  • Child Assessment of Symptoms - Do You Have Problems With Your Eyes in the Sun?(8 Weeks)
  • Compliance of Spectacle Wear(8 weeks)
  • Child Assessment of Symptoms - Do Your Eyes Feel Funny?(8 Weeks)
  • Randot Preschool Stereoacuity at Near, Continuous(8 Weeks)
  • Child Assessment of Symptoms - Is it Hard for You to Stare at Things?(8 Weeks)
  • Child Assessment of Symptoms - Do Your Eyes go in and Out?(8 Weeks)
  • Child Assessment of Symptoms - Is it Hard to Focus Your Eyes?(8 Weeks)
  • Parent Assessment of Symptoms and Spectacle Wear - Has Your Child Had Eyestrain?(8 Weeks)
  • Parent Assessment of Symptoms and Spectacle Wear - Has Your Child Reported Blurry Vision?(8 Weeks)
  • Parent Assessment of Symptoms and Spectacle Wear - Has Your Child Looked Over His or Her Spectacles?(8 Weeks)
  • Parent Assessment of Symptoms and Spectacle Wear - Has Your Child Taken His/Her Spectacles Off When he/She Should be Wearing Them?(8 Weeks)
  • Parent Assessment of Symptoms and Spectacle Wear - Has Your Child Complained That the Spectacles Hurt His/Her Ears and/or Nose?(8 Weeks)

Investigators

Sponsor
Jaeb Center for Health Research
Sponsor Class
Other
Responsible Party
Sponsor

Study Sites (56)

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