Treatment outcomes for amblyopia using PEDIG amblyopia protocols: a retrospective study of 877 cases

The landmark Pediatric Eye Disease Investigators Group (PEDIG) Amblyopia Treatment Studies (ATS) 2A and 2B concluded that 6 hours of occlusion were as efficacious as full-time occlusion in treating severe amblyopia and that 2 hours occlusion were as effective as 6 in treating moderate amblyopia. We present the first retrospective study of real-world outcomes of amblyopia treatment using PEDIG amblyopia protocols in 877 patients treated at a single center.

Electronic patient records were reviewed retrospectively to identify children meeting ATS2A (severe amblyopia) and ATS2B (moderate amblyopia) inclusion criteria who presented at the Gloucestershire Eye Unit from 2013 to 2017. Clinical data for each patient were entered during routine clinical care. Severely amblyopic children were prescribed 6 hours occlusion daily, and moderately amblyopic children 2 hours, after 12 weeks refractive adaptation.

A total of 288 children were in the ATS2A group and 589 in the ATS2B group. Of the severely amblyopic eyes, 40% achieved best-corrected visual acuity better than 0.4 logMAR at 32 weeks, increasing to 55% at 48 weeks; of the moderately amblyopic eyes, 71% achieved best-corrected visual acuity better than 0.3 logMAR at 32 weeks. The mean number of lines of visual improvement was 4.2 for severely amblyopic eyes and 2.1 for moderately amblyopic eyes.

This is the largest reported series of amblyopia treated according to PEDIG protocols. The study population achieved outcomes comparable to those demonstrated by the PEDIG studies. This audit represents a "real-world" benchmark for treatment outcomes in clinical practice.