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Vision screening in preschool children: do the data support universal screening?
1Universitäts-Augenklinik Freiburg. wolf.Lagreze@uniklinik-freiburg.de
Insights
Preschool vision screening shows potential benefits but lacks definitive proof of efficacy and cost-effectiveness. More research is needed to confirm its value in preventing vision loss.
Area of Science:
- Ophthalmology
- Public Health
- Pediatrics
Background:
- Systematic reviews in 2008 from Germany and the UK heightened public interest in preschool vision screening.
- Major national organizations published comprehensive reviews on the topic.
Purpose of the Study:
- To discuss the sensitivity, specificity, efficacy, and cost-effectiveness of preschool vision screening.
- To analyze existing national reports and relevant literature.
Main Methods:
- Review of two major national reports from Germany and the UK.
- Selective PubMed literature search for relevant studies.
- Discussion of screening test performance metrics (sensitivity, specificity, positive predictive value).
Main Results:
- Studies on preschool vision screening efficacy have methodological flaws; benefits are suggested but not proven.
- Screening tests alone have inadequate positive predictive value; number needed to treat (NNT) for preventing bilateral vision loss is 13.
- Cost-effectiveness depends on the probability of long-term benefits, such as preventing adult vision loss.
Conclusions:
- Current data are insufficient to definitively conclude on the efficacy and cost-effectiveness of preschool vision screening.
- Further clinical studies are required to establish firm conclusions.
Background:
Comprehensive, systematic reviews on the benefit of vision screening in preschool children were published in 2008 by major national organizations in both Germany and the United Kingdom. These reviews raised public interest in the topic.
Methods:
This article contains a discussion of the sensitivity, specificity, efficacy, and cost-effectiveness of preschool vision screening, on the basis of the two national reports mentioned above as well as relevant literature retrieved by a selective PubMed search.
Results:
All studies that have been published to date on the efficacy of preschool visual screening suffer from methodological flaws. The available data suggest a benefit from screening, though this has not been proven. Model calculations reveal that the positive predictive value of screening tests performed in isolation is inadequate. The authors of the two national reports applied different methods and arrived at similar, but not identical conclusions. Preschool vision screening may also be cost-effective; whether this is the case or not depends on the probability of a long-term benefit--specifically, on the probability of preventing bilateral loss of vision in adulthood. To prevent one such case, it is estimated that 13 cases of childhood amblyopia must be identified and successfully treated (number needed to treat [NNT] = 13).
Conclusion:
The available data do not allow any firm conclusion about the efficacy and cost-effectiveness of preschool vision screening. Further clinical studies are needed to answer these questions.
