Optical Treatment of Strabismic and Combined Strabismic–Anisometropic Amblyopia

Abstract

Objective To determine visual acuity improvement in children with strabismic and combined strabismic-anisometropic (combined-mechanism) amblyopia treated with optical correction alone and to explore factors associated with improvement. Design Prospective multi-center cohort study Participants 146 children 3 to <7 years old with previously untreated strabismic amblyopia (N=52) or combined-mechanism amblyopia (N=94). Methods Optical treatment was provided as spectacles (prescription based on a cycloplegic refraction) that were worn for the first time at the baseline visit. Visual acuity with spectacles was measured using the Amblyopia Treatment Study HOTV© visual acuity protocol at baseline and every 9 weeks thereafter until no further improvement in visual acuity. Ocular alignment was assessed at each visit. Main outcome measure Visual acuity 18 weeks after baseline. Results Overall, amblyopic eye visual acuity improved a mean of 2.6 lines (95% confidence interval: 2.3 to 3.0), with 75% of children improving ≥2 lines and 54% improving ≥3 lines. Resolution of amblyopia occurred in 32% (95% confidence interval: 24% to 41%) of the children. The treatment effect was greater for strabismic amblyopia than for combined-mechanism amblyopia (3.2 versus 2.3 lines, adjusted P=0.003). Visual acuity improved regardless of whether eye alignment improved. Conclusions Optical treatment alone of strabismic and combined-mechanism amblyopia results in clinically meaningful improvement in amblyopic eye visual acuity for most 3 to <7-year-old children, resolving in at least one quarter without the need for additional treatment. Consideration should be given to prescribing refractive correction as the sole initial treatment for children with strabismic or combined-mechanism amblyopia before initiating other therapies.

Ambliyopi ve Tedavisi

“…Başlangıç görme keskinliği daha iyi olanlarda ve anizometropisi daha düşük olanlarda tedavi sonucu daha iyi bulunmuştur.32 Yine daha önce tedavi edilmemiş, 3-7 yaş arasındaki şaşılığı, şaşılığı ve anizometropisi beraber olan çocuklarda sadece refraktif düzeltme ile görme keskinliğinde ortalama 2,6 sıralık artış elde etmiştir. 33 Şaşılığa bağlı ambliyopide, kombine şaşılığı ve anizometropisi olan ambliyoplara göre daha başarılı sonuç elde edilmiştir. Az sayıda şaşılığa bağlı ambliyop olguda yapılan bir çalışmada sadece refraktif düzeltme ile görme keskinliğinde ortalama 2,2 sıra artış elde edilmiştir.…”

Accommodative Performance of Children With Unilateral Amblyopia

“…This includes complete resolution of amblyopia in 27% to 30% of previously untreated children aged 3 to 8 years after 16 to 22 weeks of refractive correction. [5][6][7] Other factors, including accommodation, pupil size, higher-order monochromatic aberrations, and chromatic aberration, also contribute to retinal image quality, but among these, the accuracy of accommodative responses is likely to have the greatest contribution. 8 It is generally thought that a minimum level of accommodative effort is exerted to place the image of an object of regard within the depth of focus (DOF) of the visual system, which has been found to be 60.10 to 60.50 diopter (D) in typical adults.…”

Designing clinical trials for amblyopia

“…In a subsequent prospective observational study 7 of 146 children 3 to <7 years old with previously untreated strabismic amblyopia (n=52) or combined amblyopia (n=94), optical treatment alone was provided as spectacles based on a cycloplegic refraction (allowing plus sphere to be cut by up to +0.50D). At 18 weeks, amblyopic eye visual acuity improved a mean of 2.6 lines, with 75% of children improving ≥2 lines.…”

“…Resolution of amblyopia occurred in 32% of the children and visual acuity improved regardless of whether eye alignment improved. 7 …”