Clinical Trial: Full-time Bangerter Filters Versus Part-time Daily Patching for Moderate Amblyopia in Children

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: A Randomized Trial of Full-time Bangerter Filters Versus Part-time Daily Patching for the Treatment of Moderate Amblyopia in Children

Brief Summary:

This study is a randomized clinical trial designed to evaluate the non-inferiority of Bangerter filters compared to 2 hours of daily patching as a primary treatment for moderate amblyopia (20/40 to 20/80) in children ages 3 to < 10 years.

Secondary objectives of this study are (1) to determine the time course of visual improvement with Bangerter filter treatment, (2) to compare patient quality of life, measured by a modified Amblyopia Treatment Index, between patients treated with patching vs. Bangerter filters, (3) to determine whether blurring the sound eye to a visual acuity worse than the amblyopic eye predicts improvement in acuity, and (4) to determine whether a change in fixation to the amblyopic eye is predictive of improvement in visual acuity.

The primary outcome assessment is visual acuity at 24 weeks for both the amblyopic and sound eyes.

The primary analytic approach for the amblyopic eye acuity will involve construction of a one-sided 95% confidence interval to assess non-inferiority based on a treatment group comparison of logMAR visual acuity scores adjusted for baseline visual acuity scores in an analysis of covariance (ANCOVA) model.

Sound eye acuity data will be reported for each treatment regimen at the 24-week visit as mean change (logMAR lines) from baseline and as the distribution of the number of lines of change from baseline.


Detailed Summary:

Amblyopia is the most common cause of monocular visual impairment in children, estimated to affect as many as 3.6% of the childhood population. The natural history of amblyopia is relatively unknown although it has been reported that visual acuity may deteriorate further without treatment.

Although occlusion or patching of the sound eye has been the mainstay for amblyopia therapy, alternative treatment such as pharmacological or optical penalization may be as effective. In a randomized, controlled clinical trial of 419 children, 3 years to less than 7 years old with moderate amblyopia, patching was compared to atropine. Although improvement with atropine was initially slower, both treatments produced similar improvement after 6 months.

Although both patching and atropine have been proven effective for treating amblyopia, neither treatment is without adverse side effects. Patching is associated with compliance difficulties, the need for continuous monitoring, and social stigma. Negative side effects observed in children treated with atropine include light sensitivity, facial flushing, and fever. In a randomized clinical trial comparing patching to atropine as a treatment for amblyopia, a questionnaire to assess the impact of patching and atropine treatment on the child and family indicated that both treatments were well tolerated overall, however, patching had lower compliance and higher social stigma than atropine.

Bangerter filters, also known as Bangerter foils, have been used mainly as secondary amblyopia therapy following patching or atropine to either further improve or maintain the visual gain. One advantage of Bangerter filters compared to patching is that the lower density filters are not readily apparent and therefore would be expected to increase patient complianc
Sponsor: Jaeb Center for Health Research

Current Primary Outcome:

  • Distribution of Visual Acuity in the Amblyopic Eye at 24 Weeks [ Time Frame: 24 weeks ]
    Visual acuity was measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol resulting in a Snellen acuity score that can range from 20/16 to 20/800 for ages 3 to <7; or with the electronic early treatment diabetic retinopathy study (E-ETDRS) method for 7 to <10 year olds which resulted in a letter score that could range from 0 to 97 letters, with 0 being the worst and 97 being the best. Scores were converted to log of minimum angle of resolution (logMAR) equivalents for analyses (lower logMAR value is better than higher logMAR).
  • Mean (SD) of Amblyopic Eye Visual Acuity at 24 Weeks [ Time Frame: 24 weeks ]
    Visual acuity was measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol resulting in a Snellen acuity score that can range from 20/16 to 20/800 for ages 3 to <7; or with the electronic early treatment diabetic retinopathy study (E-ETDRS) method for 7 to <10 year olds which resulted in a letter score that could range from 0 to 97 letters, with 0 being the worst and 97 being the best. Scores were converted to log of minimum angle of resolution (logMAR) equivalents for analyses (lower logMAR value is better than higher logMAR).
  • Distribution of Change in Amblyopic Eye Visual Acuity Scores From Baseline to 24 Weeks [ Time Frame: Baseline to 24 weeks ]
    Visual acuity was measured in each eye using the Amblyopia Treatment Study (ATS) testing protocol resulting in a Snellen acuity score for 3 to <7 year olds; or with the electronic early treatment diabetic re

    Original Primary Outcome: Amblyopic and sound eye visual acuity [ Time Frame: 24 weeks ]

    Current Secondary Outcome:

    • Mean Interocular Difference at 24 Weeks [ Time Frame: 24 weeks ]
      Visual acuity was measured in each eye using the Amblyopia Treatment Study (ATS) testing protocol resulting in a Snellen acuity score for 3 to <7 year olds; or with the electronic early treatment diabetic retinopathy study (E-ETDRS) method for 7 to <10 year olds, resulting in a letter score that could range from 0 to 97 letters (0 worst; 97 best). Scores were converted to log of minimum angle of resolution (logMAR)(lower logMAR indicates better score). A positive interocular difference indicates worse acuity in the amblyopic eye (one logMAR line = 5 letters or one Snellen line).
    • Distribution of Subjects With Interocular Difference <1 logMAR Line at 24 Weeks [ Time Frame: 24 weeks ]
      Visual acuity was measured in each eye using the Amblyopia Treatment Study (ATS) testing protocol resulting in a Snellen acuity score for 3 to <7 year olds; or with the electronic early treatment diabetic retinopathy study (E-ETDRS) method for 7 to <10 year olds, resulting in a letter score that could range from 0 to 97 letters (0 worst; 97 best). Scores were converted to log of minimum angle of resolution (logMAR)(lower logMAR indicates better score). A positive interocular difference indicates worse acuity in the amblyopic eye (one logMAR line = 5 letters or one Snellen line).
    • Distribution of Subjects With >= 20/25 Amblyopic Eye Visual Acuity at 24 Weeks [ Time Frame: 24 weeks ]
      Visual acuity was measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol resulting in a Snellen acuity score that can range from 20/16 to 20/800 for ages 3 to <7; or with the electronic early treatment diabetic retinopathy study (E-ETDRS) method for 7 to <10 year olds which resulted in a letter score that could range from 0 to 97 letters, with 0 being the worst and 97 being the best. Scores were converted to log of minimum angle of resolution (logMAR) equivalents for analyses (lower logMAR value is better than higher logMAR).
    • Distribution of Subjects With 3 or More Lines of Improvement [ Time Frame: Baseline to 24 weeks ]
      Visual acuity was measured in each eye using the Amblyopia Treatment Study (ATS) testing protocol resulting in a Snellen acuity score for 3 to <7 year olds; or with the electronic early treatment diabetic retinopathy study (E-ETDRS) method for 7 to <10 year olds, resulting in a letter score that could range from 0 to 97 letters (0 worst; 97 best). Scores were converted to log of minimum angle of resolution (logMAR)(lower logMAR indicates better score). Change from baseline to 24 weeks was calculated. A positive difference indicates improvement (one logMAR line = 5 letters or one Snellen line).
    • Distribution of Patient Characteristics at the 24-week Outcome Exam. [ Time Frame: 24 weeks ]
      The distribution of the number of participants in each patient characteristic category at the 24-week outcome examination was found (for example, the number of participants at 24 weeks who were 3 to <5 years old at the time of enrollment).
    • Mean and SD of Change in Visual Acuity in the Amblyopic Eye From Baseline to 24-Week Outcome Examination According to Patient Characteristics [ Time Frame: Baseline to 24 weeks ]
      Visual acuity was measured in each eye using the Amblyopia Treatment Study (ATS) testing protocol resulting in a Snellen acuity score for 3 to <7 year olds; or with the electronic early treatment diabetic retinopathy study (E-ETDRS) method for 7 to <10 year olds, resulting in a letter score that could range from 0 to 97 letters (0 worst; 97 best). Scores were converted to log of minimum angle of resolution (logMAR)(lower logMAR indicates better score). Change from baseline to 24 weeks was calculated. A positive difference indicates improvement (one logMAR line = 5 letters or one Snellen line).
    • Distribution of Change in Randot Preschool Stereoacuity From Baseline to 24-Week Outcome by Treatment Group: All Subjects [ Time Frame: Baseline to 24 weeks ]
      The Randot Preschool Stereotest measures stereopsis from 800 to 40 seconds of arc. It is designed as a matching game in which the patient matches pictures in a test booklet wearing special glasses. A subject can fail the pretest (not see any pictures) or can score >800 (the worst), 800, 400, 200, 100, 60, or 40 (the best). If two shapes are identified correctly the patient moves to the next lower level. A failed test occurs when the patient cannot identify any shapes. A change of 1 level is a movement of 1 step in the scale (decrease shows improvement - ex. 100 to 60 is 1 level improved).
    • Distribution of Change in Randot Preschool Stereoacuity From Baseline to 24-week Outcome by Treatment Group: Subjects With Anisometropia and No Strabismus [ Time Frame: Baseline to 24 weeks ]
      The Randot Preschool Stereotest measures stereopsis from 800 to 40 seconds of arc. It is designed as a matching game in which the patient matches pictures in a test booklet wearing special glasses. A subject can fail the pretest (not see any pictures) or can score >800 (the worst), 800, 400, 200, 100, 60, or 40

      Original Secondary Outcome:

      • Time course of visual improvement with Bangerter filter treatment [ Time Frame: 24 weeks ]
      • Compare patient quality of life between patients treated with patching vs Bangerter filters [ Time Frame: 24 weeks ]
      • Determine in the Bangerter filter group whether the degree of blurring of sound eye visual acuity relative to the amblyopic eye visual acuity predicts improvement in acuity [ Time Frame: 24 weeks ]
      • Determine in the Bangerter filter group whether fixation preference is predictive of improvement in visual acuity [ Time Frame: 24 weeks ]


      Information By: Jaeb Center for Health Research

      Dates:
      Date Received: August 31, 2007
      Date Started: November 2007
      Date Completion:
      Last Updated: July 7, 2016
      Last Verified: July 2016