IXT6: Base-in Prism Spectacles for Intermittent Exotropia

Sponsor
Jaeb Center for Health Research (Other)
Overall Status
Completed
CT.gov ID
NCT03998670
Collaborator
Pediatric Eye Disease Investigator Group (Other), National Eye Institute (NEI) (NIH)
57
28
2
10
2
0.2

Study Details

Study Description

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

Condition or Disease Intervention/Treatment Phase
  • Device: Prism Glasses
  • Device: Non-Prism Glasses
N/A

Study Design

Study Type:
Interventional
Actual Enrollment :
57 participants
Allocation:
Randomized
Intervention Model:
Parallel Assignment
Masking:
Single (Outcomes Assessor)
Primary Purpose:
Treatment
Official Title:
Intermittent Exotropia Study 6: A Pilot Randomized Clinical Trial of Base-in Prism Spectacles for Intermittent Exotropia
Actual Study Start Date :
Sep 30, 2019
Actual Primary Completion Date :
Jul 30, 2020
Actual Study Completion Date :
Jul 30, 2020

Arms and Interventions

Arm Intervention/Treatment
Experimental: Prism Group

Spectacles with refractive correction and base-in relieving prism (40% of the greater of the exodeviation by prism and alternate cover test (PACT) at distance or near) equally divided between the 2 lenses will be prescribed to the participant

Device: Prism Glasses
Spectacles with refractive correction and base-in relieving prism (40% of the greater of the exodeviation by PACT at distance or near) equally divided between the 2 lenses

Placebo Comparator: Non-Prism Group

Spectacles with refractive correction (or plano spectacles if no significant refractive error) and no prism will be prescribed to the participant

Device: Non-Prism Glasses
Spectacles with refractive correction (or plano spectacles if no significant refractive error) and no prism

Outcome Measures

Primary Outcome Measures

  1. Mean Distance Control Score [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.

Secondary Outcome Measures

  1. Distance Control [8 weeks]

    The secondary analysis will calculate the proportion (and two-sided 95% confidence interval) of participants with a "treatment response," defined as ≥1 point improvement in control of their distance exodeviation (average of 3 measurements) between baseline and the 8-week outcome exam.

  2. No Spontaneous Tropia [8 Weeks]

    The proportion of participants with no spontaneous tropia at 8 weeks will be compared between treatment groups using a two-sided Barnard's test with alpha of 0.05, with calculation of a two-sided 95% confidence interval on the difference in proportions. No spontaneous tropia at the 8-week primary outcome exam is defined as a score of ≤2 (0, 1, or 2) on all three assessments of control at distance and at near.

  3. Change in Distance Control [8 Weeks]

    The distribution of change in distance control will be compared between treatment groups using the Wilcoxon rank sum test.

  4. Near Control [8 Weeks]

    Near control will be evaluated similarly to the primary outcome and outcome measures 2-4.

  5. Ocular Alignment [8 Weeks]

    The distribution of measures of ocular alignment at distance and near fixation by PACT will be described for the enrollment exam and the outcome exam for each treatment group

  6. Near Stereoacuity [8 Weeks]

    The distribution of near stereoacuity will be described for the enrollment exam and the outcome exam for each treatment group.

  7. Suppression [8 Weeks]

    As an exploratory analysis, the distribution of suppression level (none, mild, moderate, severe) will be described for the enrollment exam and the outcome exam for each treatment group.

  8. Fusional Convergence [8 Weeks]

    As an exploratory analysis, the distribution of fusional convergence amplitude (break point, blur point, and recovery) will be described, and compared between treatment groups for the enrollment exam and the outcome exam for each treatment group

  9. Adverse Symptoms of Intermittent Exotropia and Prism Spectacle Wear [8 Weeks]

    Adverse symptoms of IXT will be assessed at enrollment and at the 8-week outcome exam using a symptom survey that is administered to the child. Response options are based on frequency of observations: never, sometimes, and always. Similarly, adverse symptoms that may be associated with prism spectacle wear will be assessed at enrollment and at the 8-week outcome exam using a spectacle survey that is administered to the parent. Response options are based on frequency of observations: never, rarely, sometimes, often, always, and not applicable. For each survey separately, the distribution of scores on each survey item will be described for the enrollment exam and the outcome exam for each treatment group.

  10. Distance Visual Acuity [8 Weeks]

    Distance visual acuity will be assessed at enrollment and at the 8-week outcome exam. Any optotype method can be used for testing; however, the same method must be used at both the enrollment and 8-week outcome exam. The distribution of distance visual acuity measures will be described for the enrollment exam and the outcome exam for each treatment group. The distribution of change in visual acuity will also be described for each treatment group.

  11. Compliance of Spectacle Wear [8 weeks]

    Parents will be asked to complete a compliance calendar by recording the percentage of time their child has worn the study-prescribed spectacle correction each day. Proportion of time worn each day will be described as excellent (76% to 100%), good (51% to 75%), fair (26% to 50%), poor (1 to 25%), or none (0%). Based on review of the calendars and discussion with parents at the 8-week outcome exam, the investigator will record the total proportion of time worn as excellent (76% to 100%), good (51% to 75%), fair (26% to 50%), poor (1 to 25%), or none (0%: did not fill prescription or never picked up spectacles). The distribution of compliance will be assessed for each treatment group at the outcome exam.

Eligibility Criteria

Criteria

Ages Eligible for Study:
3 Years to 13 Years
Sexes Eligible for Study:
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

Contacts and Locations

Locations

Site City State Country Postal Code
1 UAB Pediatric Eye Care; Birmingham Health Care Birmingham Alabama United States 35294
2 Midwestern University Eye Institute Glendale Arizona United States 85308
3 Arkansas Childrens Little Rock Arkansas United States 72202
4 Southern California College of Optometry Fullerton California United States 92831-1699
5 Western University College of Optometry Pomona California United States 91766
6 Nova Southeastern University College of Optometry, The Eye Institute Fort Lauderdale Florida United States 33382
7 Ann & Robert H. Lurie Children's Hospital of Chicago Chicago Illinois United States 60611
8 Illinois College of Optometry Chicago Illinois United States 60616
9 University of Chicago Hyde Park Illinois United States 60637
10 Indiana School of Optometry Bloomington Indiana United States 47405
11 Indiana University School of Optometry Indianapolis Indiana United States 47405
12 Wolfe Eye Clinic West Des Moines Iowa United States 50266
13 University of Kentucky Department of Neurology Lexington Kentucky United States 40536
14 Wilmer Eye Institute Baltimore Maryland United States 21287-9028
15 Boston Medical Center Boston Massachusetts United States 02118
16 Boston Children's Hospital Waltham Boston Massachusetts United States 02453
17 Pediatric Ophthalmology, P.C. Grand Rapids Michigan United States 49546
18 University of Nebraska Medical Center Omaha Nebraska United States 68114
19 Cincinnati Children's Hospital Cincinnati Ohio United States 45229
20 Ohio State University College of Optometry Columbus Ohio United States 43210-1280
21 OHSU Casey Eye Institute Portland Oregon United States 97239
22 Pediatric Ophthalmology of Erie Erie Pennsylvania United States 16501
23 Salus University/Pennsylvania College of Optometry Philadelphia Pennsylvania United States 19141
24 Vanderbilt University Medical Center Nashville Tennessee United States 37232
25 Texas Children's Hospital - Dept. Of Ophthalmology Houston Texas United States 77030
26 Houston Eye Associates The Woodlands Texas United States 77381
27 Virginia Pediatric Eye Center Norfolk Virginia United States 23502
28 Gundersen Health System La Crosse Wisconsin United States 54601

Sponsors and Collaborators

  • Jaeb Center for Health Research
  • Pediatric Eye Disease Investigator Group
  • National Eye Institute (NEI)

Investigators

  • Study Chair: David G Morrison, MD, Vanderbilt University Medical Center
  • Study Chair: Allison I Summers, OD, MCR, Oregon Health and Science University

Study Documents (Full-Text)

More Information

Additional Information:

Publications

None provided.
Responsible Party:
Jaeb Center for Health Research
ClinicalTrials.gov Identifier:
NCT03998670
Other Study ID Numbers:
  • IXT6
  • 2UG1EY011751
First Posted:
Jun 26, 2019
Last Update Posted:
Sep 8, 2021
Last Verified:
Sep 1, 2021
Individual Participant Data (IPD) Sharing Statement:
Yes
Plan to Share IPD:
Yes
Studies a U.S. FDA-regulated Drug Product:
No
Studies a U.S. FDA-regulated Device Product:
No
Keywords provided by Jaeb Center for Health Research
Additional relevant MeSH terms:

Study Results

No Results Posted as of Sep 8, 2021