Vision screening for amblyopia in childhood.
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.


OBJECTIVE
The objective of this review was to evaluate the effectiveness of vision screening in reducing the prevalence of amblyopia.


METHODS
We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2008), MEDLINE (January 1950 to August 2008) and EMBASE (January 1947 to August 2008). The electronic databases were last searched on 15 August 2008. No language restrictions were placed on these searches. No handsearching was done.


METHODS
We planned to analyse data from randomised controlled trials and cluster-randomised trials comparing the prevalence of amblyopia in screened versus unscreened populations.


METHODS
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.


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.


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.
Powell
Christine
C
Department of Ophthalmology, Royal Victoria Infirmary, Claremont Wing, Queen Victoria Road, Newcastle upon Tyne, UK, NE1 4LP.
Hatt
Sarah R
SR
D000550:Amblyopia / Q000175:diagnosis* / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D006801:Humans; D015995:Prevalence; D015351:Vision Screening