Powell C, Porooshani H, Bohorquez M C, Richardson S
Cochrane Eyes and Vision Group, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK, WC1E 7HT.
Cochrane Database Syst Rev. 2005 Jul 20(3):CD005020. doi: 10.1002/14651858.CD005020.pub2.
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.
The objective of this review was to evaluate the effectiveness of vision screening in reducing the prevalence of amblyopia.
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.
We planned to analyse data from randomised controlled trials and cluster-randomised trials comparing the prevalence of amblyopia in screened versus unscreened populations.
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.
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.
