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Screening for amblyopia in childhood
C Powell1, H Porooshani, M C Bohorquez
1Cochrane Eyes and Vision Group, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK, WC1E 7HT. christine.powell@nhs.net
Insights
Vision screening aims to detect amblyopia (lazy eye) early. However, a lack of robust trials means its effectiveness in reducing lazy eye prevalence remains unproven, necessitating further research.
Area of Science:
- Ophthalmology
- Public Health
- Evidence-Based Medicine
Background:
- Amblyopia, or lazy eye, is a treatable vision deficit during critical developmental periods.
- Vision screening programs aim to identify asymptomatic amblyopia for early intervention.
- The efficacy and optimal protocols for vision screening remain subjects of debate.
Purpose of the Study:
- To evaluate the effectiveness of vision screening in reducing the prevalence of amblyopia.
Main Methods:
- Systematic review of randomized controlled trials (RCTs) and cluster-RCTs.
- Searches conducted in CENTRAL, MEDLINE, and EMBASE databases (up to May 2005).
- Independent assessment of study abstracts and full texts; author contact for data.
Main Results:
- No RCTs were identified that compared amblyopia prevalence in screened versus unscreened populations.
- Data for analysis were unavailable, and no meta-analysis was performed.
- Potential data for future updates to the review are currently in preparation.
Conclusions:
- The absence of RCT data hinders the analysis of vision screening's impact on amblyopia prevalence.
- Current evidence does not confirm or deny the benefits of vision screening; robust trials are lacking.
- Future trials require normative data, a consensus on amblyopia definition, and quantified long-term consequences.
Background:
Amblyopia is a reversible deficit of vision that has to be treated within the sensitive period for visual development. Screening programmes have been set up to detect this largely asymptomatic condition and refer children for treatment while an improvement in vision is still possible. The value of such programmes and the optimum protocol for administering them remain controversial.
Objectives:
The objective of this review was to evaluate the effectiveness of vision screening in reducing the prevalence of amblyopia.
Search Strategy:
We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Group Trials Register, on The Cochrane Library Issue 2, 2005, MEDLINE (1966 to May 2005 week 1) and EMBASE (1980 to 2005 week 19). No language restrictions were placed on these searches. No handsearching was done.
Selection Criteria:
We planned to analyse data from randomised controlled trials and cluster-randomised trials comparing the prevalence of amblyopia in screened versus unscreened populations.
Data Collection And Analysis:
Two authors independently assessed study abstracts identified by the electronic searches. Full text copies of appropriate studies were obtained and, where necessary, authors were contacted. No data were available for analysis and no meta-analysis was performed.
Main Results:
Despite the large amount of literature available regarding vision screening no trials designed to compare the prevalence of amblyopia in screened versus unscreened populations were found. Data currently under preparation may be available for updates to the review.
Authors' Conclusions:
The lack of data from randomised controlled trials makes it difficult to analyse the impact of existing screening programmes on the prevalence of amblyopia. The absence of such evidence cannot be taken to mean that vision screening is not beneficial; simply that this intervention has not yet been tested in robust trials. To facilitate such trials normative data on age-appropriate vision tests need to be available and a consensus reached regarding the definition of amblyopia. In addition, the consequences of living with untreated amblyopia have yet to be quantified and a cost-benefit analysis carried out.
