A Randomized Trial to Evaluate 2 Hours of
Daily Patching for Strabismic and
Anisometropic Amblyopia in Children
Pediatric Eye Disease Investigator Group*
Objective: To compare 2 hours of daily patching (combined with 1 hour of concurrent near visual activities)
with a control group of spectacle wear alone (if needed) for treatment of moderate to severe amblyopia in children
3 to 7 years old.
Design: Prospective randomized multicenter clinical trial (46 sites).
Participants: One hundred eighty children 3 to 7 years old with best-corrected amblyopic-eye visual acuity
(VA) of 20/40 to 20/400 associated with strabismus, anisometropia, or both who had worn optimal refractive
correction (if needed) for at least 16 weeks or for 2 consecutive visits without improvement.
Intervention: Randomization either to 2 hours of daily patching with 1 hour of near visual activities or to
spectacles alone (if needed). Patients were continued on the randomized treatment (or no treatment) until no
further improvement was noted.
Main Outcome Measure: Best-corrected VA in the amblyopic eye after 5 weeks.
Results: Improvement in VA of the amblyopic eye from baseline to 5 weeks averaged 1.1 lines in the
patching group and 0.5 lines in the control group (P = 0.006), and improvement from baseline to best measured
VA at any visit averaged 2.2 lines in the patching group and 1.3 lines in the control group (P0.001).
Conclusion: After a period of treatment with spectacles, 2 hours of daily patching combined with 1 hour of
near visual activities modestly improves moderate to severe amblyopia in children 3 to 7 years old.
Ophthalmology 2006;113:904 –912 © 2006 by the American Academy of Ophthalmology.
Amblyopia is a leading cause of monocular visual impair-
ment.
1,2
In previous studies, we reported similar effective-
nesses for 6 hours versus 2 hours of prescribed patching per
day for moderate amblyopia and for full-time versus 6 hours
of prescribed patching for severe amblyopia.
3,4
Despite expert opinion
5,6
and experimental evidence that
amblyopia improves with patching,
3,4,7
some authors
8 –10
have questioned whether there is benefit to patching, be-
cause few studies have included an untreated control group.
Although results from randomized clinical trials comparing
patching with a control have been reported,
11,12
no study
has been published to date that has done all of the following:
(1) clearly defined amblyopia at enrollment, (2) incorpo-
rated a prolonged spectacles run-in phase with criteria for
determining when maximum improvement occurs, and
(3) included a no-patching control group.
To address the question of whether patching improves
amblyopia after a period of refractive correction, we con-
ducted a randomized clinical trial to compare the effect of 2
hours of daily patching combined with 1 hour of near
activities versus a control group in children ages 3 to 7 years
with amblyopia caused by strabismus, anisometropia, or
both.
Patients and Methods
The study, supported through a cooperative agreement with the
National Eye Institute of the National Institutes of Health, was
conducted by the Pediatric Eye Disease Investigator Group at 46
clinical sites. The protocol and Health Insurance Portability and
Accountability Act– compliant informed consent forms were ap-
proved by institutional review boards, and the parent or guardian
(referred to subsequently as parent) of each study patient gave
written informed consent. Study oversight was provided by an
independent data and safety monitoring committee.
Patient Selection
Eligibility criteria included age 3 to 7 years (at the time of
enrollment) and the presence of or a history of an amblyogenic
factor meeting study-specified criteria for strabismus and/or aniso-
metropia (Table 1). At the time of randomization, the primary
cohort required visual acuity (VA) in the amblyopic eye to be
between 20/40 and 20/400 inclusive, VA in the sound eye to be
20/40 or better, and an interocular acuity difference of 3 lines
(0.3 logarithm of the minimum angle of resolution [logMAR]). A
Originally received: November 17, 2005.
Accepted: January 24, 2006. Manuscript no. 2005-1118.
Supported by the National Eye Institute, Bethesda, Maryland (cooperative
agreement no.: EY11751).
Correspondence to David K. Wallace, MD, c/o Jaeb Center for Health
Research, 15310 Amberly Drive, Suite 350, Tampa, FL 33647. E-mail:
pedig@jaeb.org.
*See “Acknowledgments” for the writing committee and where to find a
list of the members of the Group participating in the trial.
904 © 2006 by the American Academy of Ophthalmology ISSN 0161-6420/06/$–see front matter
Published by Elsevier Inc. doi:10.1016/j.ophtha.2006.01.069