IXT6: Base-in Prism Spectacles for Intermittent Exotropia
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 |
---|---|---|
|
N/A |
Study Design
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
- 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
- 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.
- 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.
- 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.
- Near Control [8 Weeks]
Near control will be evaluated similarly to the primary outcome and outcome measures 2-4.
- 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
- Near Stereoacuity [8 Weeks]
The distribution of near stereoacuity will be described for the enrollment exam and the outcome exam for each treatment group.
- 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.
- 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
- 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.
- 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.
- 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
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.- IXT6
- 2UG1EY011751