Study highlights lack of information about the global prevalence of childhood cataracts
Researchers at City, University of London have conducted the first systematic review of the prevalence and incidence of childhood cataracts worldwide.
The study, which reviewed studies from around the globe, found that there are still substantial gaps in the knowledge of childhood cataract prevalence and incidence, particularly from low income economies. As a result, further studies are urgently needed to address this public health problem and the issue of childhood blindness.
Childhood cataract is the major cause of treatable blindness in children in developing countries. The City review estimates that there are approximately 191,000 cases of childhood cataract worldwide, and around 314,000 new childhood cataract - both developmental and inherited - cases every year.
However, the current lack of specific knowledge when it comes to prevalence and incidence rates in many countries is preventing adequate identification, policy and treatment of the disease according to the authors. The study is published in the journal Eye.
Cataract occurs due to a clouding of the lens in the eye leading to a decrease in vision. It occurs normally in the aging eye, but in children cataracts may be inherited or acquired, and can occur in one or both eyes. Although it is rare, cataract is one of the most common causes of blindness and severe visual impairment in children and is responsible for as much as 20 per cent of paediatric blindness worldwide. Cataract blindness in children presents an enormous problem to developing countries in terms of human morbidity, economic loss, and social burden.
To assess the global prevalence of childhood cataract, the City, University of London researchers performed a literature search for studies reporting estimates of prevalence or incidence of cataract among children aged less than 18 years at any global location using the Cochrane Library, Medline and Embase up to January 2015. Twenty prevalence and four incidence studies of childhood cataract from five different geographical regions were included.
The researchers found that the median prevalence for childhood cataract was 1.03 per 10,000 children, and a median incidence of 1.69 per 10,000. There was a similar prevalence for childhood cataracts occurring in one or two eyes. Both have significant impact on vision in different ways.
Speaking about the study, Ms Sheeladevi Sethu, a PhD scholar in ophthalmic public health at City, University of London, said:
"Cataracts are responsible for a large proportion of childhood blindness, but the good news is that they are treatable. Our new review has highlighted substantial gaps in the epidemiological knowledge of childhood cataract worldwide that urgently needs to be addressed, particularly from low and lower middle-income economies, where the burden of childhood cataract is presumed to be high.
"More studies are needed using standardised definitions and methods with large enough sample sizes, as these estimates could then inform policy decisions to prioritise funding of programs to reduce visual impairment and blindness due to childhood cataract at regional and global levels. Delivering timely surgical intervention and appropriate follow-up after surgery would avoid blindness in children due to cataract, as emphasised and advocated by the Vision 2020 initiative: The Right to Sight Initiative."
