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D.E. Bustos, S.P. Donahue; Evaluation Of Bangerter Filters As A Predictable Means Of Blurring Vision . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2457.
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© ARVO (1962-2015); The Authors (2016-present)
Occlusion therapy has been the gold standard treatment of amblyopia for many years. One of the major barriers to successful treatment is compliance related to discomfort from wearing the patch. While originally designed and marketed as an alternative to occlusion therapy many years ago, Bangerter occlusion foils have not been widely accepted as a viable treatment option, and have not been prospectively evaluated as a means of amblyopia treatment. The purpose of this study is to evaluate the effectiveness of Bangerter occlusion foils to predictably blur vision in healthy adults with normal best–corrected visual acuity.
Prospective, randomized, single–masked design.
Twenty adults with best–correctable visual acuity of at least 20/20 (Snellen) and no history of ocular disease affecting visual acuity underwent visual acuity examination using the E–ETDRS electronic visual acuity system previously used in prior Amblyopia Treatment Study (ATS) Investigations. E–ETDRS visual acuity was tested in both eyes without Bangerter filters and in one eye (randomly determined) occluded with three Bangerter filters of variable densities: 0.2, 0.1 and < 0.1.
Mean E–ETDRS visual acuity measured in both filtered and unfiltered eyes was 87.2 and 88.2 letters, respectively (approximately 20/20 Snellen equivalent). Visual acuity was degraded to, on average, 61 letters (range 55–67) with the 0.2 filter (approximately 20/63 Snellen equivalent), 31 letters (range 28–37) with the 0.1 filter (approximately 20/250 Snellen equivalent), and 43 letters (range 32–52) with the < 0.1 filter (approximately 20/160 Snellen equivalent).
Bangerter occlusion foils predictably blur vision in normal, healthy adults without ocular pathology. However, the 0.1 filter provides a more consistent and reliable degradation of acuity than the <0.1 filter. If similar results are found in healthy children, Bangerter occlusion foils may be an effective means of pediatric visual penalization. A randomized controlled study of this method of visual penalization in the treatment of amblyopia may be warranted.
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