Effectiveness of Early in Comparison to Late(r) Treatment in Children with Amblyopia or Its Risk Factors: A Systematic Review

Abstract

Purpose: To evaluate the effectiveness of early in comparison to late(r) treatment in children with (1) amblyopia or (2) its risk factors, such as refractive errors and strabismus.

Methods: Eight bibliographic databases were searched with no limitation to a specific year of publication or language. Studies including children and juveniles with amblyopia or its risk factors were considered for this review.

Results: In total, five studies (three direct comparisons within one study; one indirect comparison between two studies) met the inclusion criteria. (1) Treatment of amblyopia: one comparison suggested that amblyopia treatment in preschool children is more effective than treatment later in life. However, a subgroup analysis of children who have never received any treatment indicated that patching may also have an effect after the “sensitive phase.” The second comparison showed that a delay in treatment until the age of 5 did not seem to influence effectiveness. (2) Treatment of amblyogenic risk factors: two comparisons showed that hyperopia treatment and strabismus surgery (outcome: remaining amblyopia) is more effective under 2 years of age than later in life. However, the studies showed methodological weaknesses (for example, a high loss to follow-up, unmasked outcome assessments) limiting the validity of their findings. The current literature does not provide data evaluating quality of life or school performance.

Conclusions: Uncertainties remain about the age at which treatment for amblyopia or its risk factors is most effective. Beside methodological limitations, the design of the studies made it challenging to address this question sufficiently.

KEYWORDS::

• Amblyopia
• Amblyogenic risk factors
• Systematic review
• Treatment
• Children

ACKNOWLEDGMENTS

JK, RG and SL developed the protocol and design of the study. Study selection and data extraction were carried out by CS, JK, RG, RR and SL. WL provided clinical advice and GA provided methodological support. All authors were involved in data interpretation and had full access to all of the data. CS wrote the paper. All authors commented on drafts of the paper and approved the final version.

Declaration of Interest: The project was referred by the Federal Joint Committee (Gemeinsamer Bundesausschuss, Auf dem Seidenberg 3a, 53721 Siegburg, Germany) to the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen [IQWiG], Dillenburger Str. 27, 51105 Cologne, Germany).

IQWiG commissioned the review prepared from Kleijnen Systematic Reviews Ltd and the German Cochrane Center. IQWiG prepared the final version of the full study report on which this paper is based and funded the researchers and authors, respectively.

APPENDIX A

Search Strategy in Ovid: MEDLINE