Boston Amblyopia Study 1: Complete Resolution of Subthreshold Amblyopia with Standard Clinical Treatment
Suzanne M. Michalak, MD; Kaila M. Bishop, BA; Talia N. Shoshany, BA; David G. Hunter, MD, PhD
Boston Children’s Hospital
Boston, MA, USA
Introduction: Published studies of amblyopia include only patients with visual acuity (VA) worse than 0.30 logMAR bilaterally or an interocular VA difference (IOD) of >/=2 lines. This study examines the outcomes of patients who were coded as and treated for amblyopia despite not meeting official criteria for amblyopia.
Methods: Retrospective review of 4096 patients seen at a teaching hospital from 2010-2015 and coded as amblyopic. Unilateral amblyopia was defined as IOD >/=0.14 with VA <0.30 in one eye; bilateral was defined as VA >/=0.30 bilaterally. Statistical analysis was performed using Wilcoxon signed-ranked test within groups.
Results: Of 642 patients reviewed to date, 48 did not meet traditional criteria for either bilateral or unilateral amblyopia but had an IOD >0. Half (24 patients, 67% male) returned for follow-up. No follow-up visit was requested for 13 patients; another 11 were lost to follow-up. The average age at treatment initiation was 7.1±4.0 years and average length of follow-up was 2.8±1.8 years. Patients improved significantly with traditional amblyopia therapy (median IOD_initial =0.08, IOD_final =0.00, p =.007), with over half achieving a VA of 0.0 bilaterally. For patients who were treatment naive, 88% achieved a final visual acuity of 0.0.
Discussion: Patients with IOD <0.14 do not meet published diagnostic criteria for amblyopia and thus do not always receive treatment. When offered treatment, visual acuity improves significantly and usually reaches 0.0 (20/20) or better.
Conclusion: Patients with any IOD should be offered treatment for amblyopia.
References: American Academy of Ophthalmology Pediatric Ophthalmology/Strabismus Panel. Preferred Practice Pattern®Guidelines. Amblyopia. San Francisco, CA: American Academy of Ophthalmology; 2012. Available at: www.aao.org/ppp.
Koo, Euna B., Aubrey L. Gilbert, and Deborah K. VanderVeen. “Treatment of amblyopia and amblyopia risk factors based on current evidence.” Seminars in ophthalmology. Vol. 32. No. 1. Taylor & Francis, 2017