A pilot randomized clinical trial of intermittent occlusion therapy liquid crystal glasses versus traditional patching for treatment of moderate unilateral amblyopia

Abstract

INTRODUCTION This pilot study was designed to compare the effectiveness of intermittent occlusion therapy (IO-Therapy) using liquid crystal glasses versus continuous occlusion therapy using traditional adhesive patches for treating amblyopia. DESIGN A randomized controlled trial. Children 3–8 years of age with previously untreated, moderate, unilateral amblyopia (visual acuity of 20/40 to 20/100 in the amblyopic eye) were enrolled. Amblyopia was associated with strabismus, anisometropia, or both. All subjects had worn optimal refractive correction (if needed) for at least 12 weeks without improvement. Subjects were randomized into two treatment groups: a 4-hour IO-Therapy Group with liquid crystal glasses (Amblyz™), set at 30-second opaque/transparent intervals (occluded 50% of wear time) or a 2-hour continuous Patching Group (occluded 100% of wear time). For each patient, visual acuity was measured with the ATS-HOTV method before and after 12 weeks of treatment. RESULTS At the conclusion of the first 12 week-treatment interval, data from 34 patients were available for analysis. Amblyopic eye visual acuity improvement from baseline was 0.15±0.12 (95% CI=0.09 to 0.15) logMAR in the IO-Therapy Group (N=19) and 0.15±0.11 (95% CI=0.1 to 0.15) logMAR in the Patching Group (N=15). Improvements in both groups were significant. The difference between groups was not statistically significant (P=0.73). No adverse effects were reported. CONCLUSION In this pilot study, IO-Therapy with Amblyz liquid crystal glasses is not inferior to adhesive patching and is a promising alternative treatment for children 3–8 years of age with moderate amblyopia. A larger randomized clinical trial is needed to confirm results in future.

Amblyopia Preferred Practice Pattern®

“…There a few publications suggesting efficacy, 189,190 and one prospective report finds that they are similar to patching in effectiveness. 191…”

Patching and Suppression in Amblyopia: One Mechanism or Two?

“…We recruited 10 children with amblyopia (two with strabismus and eight without strabismus) in this study. Although this sample size might appear to be too small to show a robust result, it had been chosen based on previous studies (Moseley et al, 1997;Pediatric Eye Disease Investigator Group Writing Committee Rutstein et al, 2010;Kehrein et al, 2016;Wang et al, 2016;Zhou et al, 2019). For example, the minimum sample size of six patients is adequate to achieve a power greater than 80% in detecting a visual acuity gain of 0.15 ± 0.12 logMAR (data from Wang et al, 2016).…”

“…Although this sample size might appear to be too small to show a robust result, it had been chosen based on previous studies (Moseley et al, 1997;Pediatric Eye Disease Investigator Group Writing Committee Rutstein et al, 2010;Kehrein et al, 2016;Wang et al, 2016;Zhou et al, 2019). For example, the minimum sample size of six patients is adequate to achieve a power greater than 80% in detecting a visual acuity gain of 0.15 ± 0.12 logMAR (data from Wang et al, 2016). Similarly, the minimum sample size of two patients is adequate to achieve a power greater than 80% if the expected binocular gain in terms of the effective contrast ratio is 0.11 ± 0.055 (data from Zhou et al, 2019).…”

Digital and Technical Developments in the Amblyopia Therapy

“…Eine weitere Studie mit 34 amblyopen Kindern zeigte keinen Unterschied im Therapieerfolg zwischen der Shutterbrille (4 h Tragen der Shutterbrille und 50 % Okklusionszeit) und der klassischen Pflasterokklusion des Führungsauges für 2 h/Tag [19]. Bei den be-handelten Amblyopien handelte es sich um moderate Amblyopien mit einem dezimalen Visus zwischen 0,2 und 0,5 am amblyopen Auge.…”