Clinical trial NCT00525174: Full-time Bangerter Filters Versus Part-time Daily Patching for Moderate Amblyopia in Children
Official title: A Randomized Trial of Full-time Bangerter Filters Versus Part-time Daily Patching for the Treatment of Moderate Amblyopia in Children
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Amblyopia
Keywords: Amblyopia
Patching
Bangerter filters
Lead sponsor: Jaeb Center for Health Research
Sponsor class: OTHER
Collaborators: name: National Eye Institute (NEI)
First posted: 2007-09-05
Enrollment: 186
Sex: ALL
Minimum age (years): 3
Maximum age (years): 9
Standard ages: CHILD
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

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 description: 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 compliance due to reduced social stigma. Another advantage of Bangerter filters is that there is no opportunity for skin irritation from bandage adhesive, a commonly-reported side effect of patching. In addition, there is a theoretical advantage that Bangerter filters are less disruptive to binocular function during treatment compared to other modalities such as patching.

Few data are available comparing Bangerter filters with patching for the treatment of amblyopia. Bonsall randomized 14 patients, 3 to 10 years old, with previously untreated strabismic/anisometropic amblyopia to either 6 hours of daily patching or full-time Bangerter filters. Baseline amblyopic eye acuity was 20/30 to 20/400 for the patching group and 20/30 to 20/200 for the Bangerter group. The Bangerter filter prescribed was the minimum density foil needed to elicit a switch in fixation from the sound eye to the amblyopic eye. Visual acuity was measured every 6-8 weeks until the amblyopic eye visual acuity was equal to that of the sound eye, an improvement that was achieved in 5 of the 14 at the time the study was stopped. The average time to achieve equal vision between the amblyopic and sound eyes was about 4.5 months (142 days) for the foil group versus about 9 months (272 days) for the patching group. Both forms of therapy were equally tolerated. Despite good preliminary data, a large randomized clinical trial comparing the effectiveness of Bangerter filters to patching for the treatment of amblyopia has yet to be conducted.

Eligibility criteria: Inclusion Criteria:

* Age 3 to \< 10 years
* Amblyopia associated with strabismus, anisometropia, or both
* No ocular cause apparent for reduced visual acuity
* Visual acuity 20/40 to 20/80 (71 to 54 letters inclusive) in amblyopic eye
* Visual acuity 20/40 or better (\>= 69 letters) in sound eye
* Interocular difference \>= 3 logMAR lines (\>= 15 letters)
* No amblyopia treatment other than spectacles in last 6 months

  \*Any treatment more than 6 months prior to enrollment is acceptable
* Currently wearing spectacles
* Appropriate spectacles have been worn for 16 weeks prior to enrollment or visual acuity documented to be stable
* No myopia \> -6.00 D spherical equivalent in either eye
* Cycloplegic refraction within 6 months prior to enrollment
* Ocular examination within 6 months prior to enrollment

Exclusion Criteria:

* Current vision therapy or orthoptics
* Ocular cause for reduced visual acuity
* Prior intraocular or refractive surgery
* Known skin reactions to patch or bandage adhesives

Primary outcomes:
measure: Distribution of Visual Acuity in the Amblyopic Eye at 24 Weeks
timeFrame: 24 weeks
measure: Mean (SD) of Amblyopic Eye Visual Acuity at 24 Weeks
timeFrame: 24 weeks
measure: Distribution of Change in Amblyopic Eye Visual Acuity Scores From Baseline to 24 Weeks
timeFrame: Baseline to 24 weeks
measure: Mean Change in Amblyopic Eye Visual Acuity From Baseline to 24 Weeks
timeFrame: Baseline to 24 weeks
Secondary outcomes:
measure: Mean Interocular Difference at 24 Weeks
timeFrame: 24 weeks
measure: Distribution of Subjects With Interocular Difference <1 logMAR Line at 24 Weeks
timeFrame: 24 weeks
measure: Distribution of Subjects With >= 20/25 Amblyopic Eye Visual Acuity at 24 Weeks
timeFrame: 24 weeks
measure: Distribution of Subjects With 3 or More Lines of Improvement
timeFrame: Baseline to 24 weeks
measure: Distribution of Patient Characteristics at the 24-week Outcome Exam.
timeFrame: 24 weeks
measure: Mean and SD of Change in Visual Acuity in the Amblyopic Eye From Baseline to 24-Week Outcome Examination According to Patient Characteristics
timeFrame: Baseline to 24 weeks
measure: Distribution of Change in Randot Preschool Stereoacuity From Baseline to 24-Week Outcome by Treatment Group: All Subjects
timeFrame: Baseline to 24 weeks
measure: Distribution of Change in Randot Preschool Stereoacuity From Baseline to 24-week Outcome by Treatment Group: Subjects With Anisometropia and No Strabismus
timeFrame: Baseline to 24 weeks
measure: Distribution of Change in Fellow Eye Visual Acuity From Baseline to 24 Weeks
timeFrame: Baseline to 24 weeks
measure: Mean Change in Fellow Eye Visual Acuity From Baseline to 24 Weeks
timeFrame: Baseline to 24 weeks
measure: Impact of Treatment on Patient and Family at 6 Weeks
timeFrame: 6 weeks
measure: Impact of Treatment on Patient and Family at 24 Weeks
timeFrame: 24 weeks
measure: Adverse Effects of Treatment on Patient and Family at 6 Weeks
timeFrame: 6 weeks
measure: Adverse Effects of Treatment on Patient and Family at 24 Weeks
timeFrame: 24 weeks
measure: Compliance With Treatment at 6 Weeks
timeFrame: 6 weeks
measure: Compliance With Treatment at 24 Weeks
timeFrame: 24 weeks
measure: Social Stigma From Treatment at 6 Weeks
timeFrame: 6 weeks
measure: Social Stigma From Treatment at 24 Weeks
timeFrame: 24 weeks
Other outcomes:
Locations:
city: Birmingham
country: United States
facility: University of Alabama at Birmingham
state: Alabama
Study officials:
affiliation: University of Alabama at Birmingham
name: Robert P. Rutstein, O.D., M.S.
role: STUDY_CHAIR
affiliation: Children's Hospital of Philadelphia
name: Graham E. Quinn, M.D., MSCE
role: STUDY_CHAIR
References:
citation: Pediatric Eye Disease Investigator Group Writing Committee; Rutstein RP, Quinn GE, Lazar EL, Beck RW, Bonsall DJ, Cotter SA, Crouch ER, Holmes JM, Hoover DL, Leske DA, Lorenzana IJ, Repka MX, Suh DW. A randomized trial comparing Bangerter filters and patching for the treatment of moderate amblyopia in children. Ophthalmology. 2010 May;117(5):998-1004.e6. doi: 10.1016/j.ophtha.2009.10.014. Epub 2010 Feb 16.
citation: Rutstein RP, Foster NC, Cotter SA, Kraker RT, Lee DH, Melia M, Quinn GE, Tamkins SM, Wallace DK; Pediatric Eye Disease Investigator Group. Visual acuity through Bangerter filters in nonamblyopic eyes. J AAPOS. 2011 Apr;15(2):131-4. doi: 10.1016/j.jaapos.2010.11.015. Epub 2011 Mar 21.
citation: Wallace DK, Lazar EL, Melia M, Birch EE, Holmes JM, Hopkins KB, Kraker RT, Kulp MT, Pang Y, Repka MX, Tamkins SM, Weise KK; Pediatric Eye Disease Investigator Group. Stereoacuity in children with anisometropic amblyopia. J AAPOS. 2011 Oct;15(5):455-61. doi: 10.1016/j.jaapos.2011.06.007.