Article Text

Original research
Efficacy of vision-based treatments for children and teens with amblyopia: a systematic review and meta-analysis of randomised controlled trials
  1. Taylor Adrian Brin1,
  2. Amy Chow1,
  3. Caitlin Carter2,
  4. Mark Oremus3,
  5. William Bobier1,
  6. Benjamin Thompson1,4,5
  1. 1Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
  2. 2Library, University of Waterloo, Waterloo, Ontario, Canada
  3. 3Public Health and Health Systems, University of Waterloo, Waterloo, Ontario, Canada
  4. 4Center for Eye and Vision Research, 17W Science Park, Hong Kong, Hong Kong
  5. 5Liggins Institute, University of Auckland, Auckland, New Zealand
  1. Correspondence to Mrs Taylor Adrian Brin; ta2brin{at}


Objective To identify differences in efficacy between vision-based treatments for improving visual acuity (VA) of the amblyopic eye in persons aged 4–17 years old.

Data sources Ovid Embase, PubMed (Medline), the Cochrane Library, Vision Cite and Scopus were systematically searched from 1975 to 17 June 2020.

Methods Two independent reviewers screened search results for randomised controlled trials of vision-based amblyopia treatments that specified change in amblyopic eye VA (logMAR) as the primary outcome measure. Quality was assessed via risk of bias and GRADE (Grading of Recommendations, Assessment, Development, and Evaluations).

Results Of the 3346 studies identified, 36 were included in a narrative synthesis. A random effects meta-analysis (five studies) compared the efficacy of binocular treatments versus patching: mean difference −0.03 logMAR; 95% CI 0.01 to 0.04 (p<0.001), favouring patching. An exploratory study-level regression (18 studies) showed no statistically significant differences between vision-based treatments and a reference group of 2–5 hours of patching. Age, sample size and pre-randomisation optical treatment were not statistically significantly associated with changes in amblyopic eye acuity. A network meta-analysis (26 studies) comparing vision-based treatments to patching 2–5 hours found one statistically significant comparison, namely, the favouring of a combination of two treatment arms comparing combination and binocular treatments, against patching 2–5 hours: standard mean difference: 2.63; 95% CI 1.18 to 4.09. However, this result was an indirect comparison calculated from a single study. A linear regression analysis (17 studies) found a significant relationship between adherence and effect size, but the model did not completely fit the data: regression coefficient 0.022; 95% CI 0.004 to 0.040 (p=0.02).

Conclusion We found no clinically relevant differences in treatment efficacy between the treatments included in this review. Adherence to the prescribed hours of treatment varied considerably and may have had an effect on treatment success.

  • child health (paediatrics)
  • treatment other
  • visual perception

Data availability statement

Data are available upon request.

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Data availability statement

Data are available upon request.

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  • Contributors All authors contributed to this project. The responsibilities were as follows: TAB: literature screening, data analysis, writing manuscript, editing manuscript. AC: literature screening, editing manuscript. CC: forming search strategy, literature search, editing manuscript. MO: data analysis, consultation, editing manuscript. WB: project inception, developing search strategy, editing manuscript, guiding the project. BT: editing manuscript, guiding the project.

  • Funding This research project received funding from the Canadian Optometric Education Trust Fund (COETF), The Natural Sciences and Engineering Research Council of Canada (NSERC), and the Canadian Institutes of Health Research (CIHR; grant 156174).

  • Competing interests BT holds two patents for a binocular treatment of amblyopia included in this review.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.