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Effectiveness of screening preschool children for amblyopia: a systematic review
Christine Schmucker1, Robert Grosselfinger, Rob Riemsma
1Department of Medical Biometry and Statistics (German Cochrane Center), Institute of Medical Biometry and Medical Informatics, University Medical Center, Freiburg, Germany. schmucker@cochrane.de
Insights
Preschool vision screening may reduce amblyopia prevalence in children. However, current evidence is limited by study weaknesses, necessitating further research for definitive conclusions on program effectiveness.
Area of Science:
- Ophthalmology
- Pediatric Vision Care
- Public Health
Background:
- Amblyopia and related factors like strabismus and refractive errors are common childhood vision impairments.
- Preschool vision screening programs aim to reduce amblyopia prevalence, but their effectiveness remains debated.
- This systematic review evaluates vision outcomes associated with preschool vision screening in children up to age six.
Purpose of the Study:
- To systematically review the literature on the effectiveness of preschool vision screening for amblyopia.
- To assess the impact of screening programs on vision outcomes in young children.
- To identify limitations in current research and guide future studies.
Main Methods:
- A systematic search of ten bibliographic databases was conducted.
- Included studies comprised randomized controlled trials, non-randomized controlled trials, and cohort studies.
- Handsearching of bibliographies supplemented the database search.
Main Results:
- Five studies met the inclusion criteria; three suggested screening reduced amblyopia prevalence (0.9%-1.6% absolute reduction).
- Significant limitations in study validity and reliability were identified, including selective analysis of participants and insufficient statistical power.
- Quality of life and adverse effects of screening were inadequately investigated.
Conclusions:
- Current literature does not sufficiently support population-based preschool vision screening programs.
- Significant methodological weaknesses in existing studies limit definitive conclusions.
- Future research should address identified limitations to better evaluate screening program efficacy.
Background:
Amblyopia and amblyogenic factors like strabismus and refractive errors are the most common vision disorders in children. Although different studies suggest that preschool vision screening is associated with a reduced prevalence rate of amblyopia, the value of these programmes is the subject of a continuing scientific and health policy discussion. Therefore, this systematic review focuses on the question of whether screening for amblyopia in children up to the age of six years leads to better vision outcomes.
Methods:
Ten bibliographic databases were searched for randomised controlled trials, non-randomised controlled trials and cohort studies with no limitations to a specific year of publication and language. The searches were supplemented by handsearching the bibliographies of included studies and reviews to identify articles not captured through our main search strategy.
Results:
Five studies met the inclusion criteria. Of these, three studies suggested that screening is associated with an absolute reduction in the prevalence of amblyopia between 0.9% and 1.6% (relative reduction: between 45% and 62%). However, the studies showed weaknesses, limiting the validity and reliability of their findings. The main limitation was that studies with significant results considered only a proportion of the originally recruited children in their analysis. On the other hand, retrospective sample size calculation indicated that the power based on the cohort size was not sufficient to detect small changes between the groups. Outcome parameters such as quality of life or adverse effects of screening have not been adequately investigated in the literature currently available.
Conclusion:
Population based preschool vision screening programmes cannot be sufficiently assessed by the literature currently available. However, it is most likely that the present systematic review contains the most detailed description of the main limitations in current available literature evaluating these programmes. Therefore, future research work should be guided by the findings of this publication.
