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Laura Smith, Catherine Stewart, Alistair R Fielder, Merrick J Moseley, Michael Wallace; A personalized approach to occlusion therapy for amblyopia.. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2194.
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© ARVO (1962-2015); The Authors (2016-present)
To use data of previous research in to the treatment of amblyopia to generate a computerised model for patching strategies to treat childhood amblyopia.
Statistical modelling analysis was undertaken on a combined data set based on MOTAS (Stewart et al., 2004) and ROTAS (Stewart et al., 2007) studies. We considered an approach that aimed to prescribe a patient's total effective occlusion dose (TED) to be converted to a daily patching for a fixed follow-up period. We assumed that every patient has an optimal visual outcome, and total effective dose of occlusion which they must undertake to achieve it.
In MOTAS and ROTAS there were occlusion data for 149 participants; amblyopia associated with anisometropia in 50, strabismus in 43, and mixed in 56 participants. Median time to optimized visual acuity was 63 days (25% and 75% quartiles of 28 and 91 days respectively). Median visual acuity in the amblyopic eye at start of occlusion was 0.40 logMAR (quartiles 0.22 and 0.68 logMAR). Median residual visual acuity (interocular difference) was 0.34 logMAR (quartiles 0.23 and 0.64 logMAR). Median lower estimate of total effective dose was 120 hours (quartiles 34 and 242 hours), median upper estimate was 176 hours (quartiles 84 and 316 hours). Exploratory plots depict a piecewise linear relationship (p = 0.008) with breakpoint estimated at 2.16 (standard error 0.51) hours/ day. The 2-part model is characterized by a steep gradient from 0 to 2.16 hours a day, followed by a shallower gradient for dose rates above this (figure 1).<br /> Our first model highlighted age, sex, gender, amblyopia type and residual amblyopia as possible predictors of total effective dose. Those with worse amblyopia at start of occlusion tended to have a larger total effective dose. Patients who were older at start of occlusion tended to have a lower total effective dose.
We have presented a new approach to the prescription of occlusion therapy for the treatment of amblyopia in children. We have introduced the concept of total effective dose of occlusion: the total dose a patient requires of occlusion before it stops being effective. Total effective dose depends on the patient's residual amblyopia, amblyopia type, and age at the start of occlusion therapy. Dose-rates prescribed range from 2.5 to 12 hours/ day.
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