Treatment Outcomes for Amblyopia Using PEDIG Amblyopia Protocols – A Prospective Study of 852 Cases
Miranda Buckle, FRCOphth; John D. Ferris, FRCOphth; Parth Shah, FRANZCO; Catherine Billington, DBO
Gloucestershire Eye Unit
Introduction: The landmark PEDIG ATS2a and ATS2b studies concluded that 6 hours of occlusion were as efficiacious as full-time occlusion in a cohort of 175 children with severe amblyopia (logmar 0.7-1.3), and that 2 hours of occlusion were as effective as 6 hours, in a cohort of 189 children with moderate ambylopia (logmar 0.3-0.6). This is the first prospective analysis of ‘real-world’ outcomes of amblyopia treatment using PEDIG amblyopia protocols.
Methods: Using the Medisoft EMR audit tool we identified a cohort of 280 children who met the ATS2a inclusion criteria, and 572 children who met the ATS2b inclusion criteria. The mean pre-treatment visual acuity (VA) in the amblyopic eye, mean age at presentation and type of amblyopia were almost identical to the ATS2a and ATS2b cohorts. Severe ambylopes were prescribed 6 hrs occlusion per day, and moderate ambylopes 2 hours occlusion per day, after a period of at least 12 weeks refractive adaptation. The audit tool compared VA in the amblyopic eye at baseline, with best-corrected VA (BCVA) at 32, 48 and 64 weeks.
Results: In ATS2a and ATS2b, 67% of severely amblyopic eyes achieved BCVA ≥ 0.4 at 17 weeks, and 81% of moderately ambylopic eyes achieved BCVA ≥0.3. In our cohort, 44% of severely ambylopic eyes achieved BCVA ≥ 0.4 at 32 weeks, increasing to 59% at 48 weeks. 74% of moderately amblyopic eyes achieved BCVA ≥ 0.3 at 32 weeks. The mean number of lines of visual improvement was 4.3 for severe ambylopes versus 4.8 in ATS2a, and 2.2 for moderate ambylopes versus 2.4 in the ATS2b study.
Discussion: Although PEDIG reported outcomes at 17 weeks, this did not include the period of refractive adaptation and our 32 week data is therefore likely to be equivalent to PEDIG 17 week data. Our ‘real-world’ data shows that acuities continued to improve up to 32 weeks for moderate ambylopes, and up to 48 weeks in severe ambylopes, but not beyond these periods.
Conclusion: This is the largest reported series of children with amblyopia treated according to PEDIG protocols. The Medisoft EMR is a powerful tool for analysing amblyopia treatment outcomes.
Holmes JM, Kraker RT, Beck RW, et al. Ophthalmology. 2003 Nov;110(11):2075-87. A randomized trial of prescribed patching regimens for treatment of severe amblyopia in children.
Repka MX, Beck RW, Holmes JM, et al. Arch Ophthalmol. 2003 May; 121(5):603-11. A randomized trial of patiching regimens for treatment of moderate amblyopia in children.