"Some children do receive vision screening in school - this is usually done around the age of five. The primary aim is to find those children with reduced vision or binocular vision problems, so they can be referred to a local optometrist or hospital eye service for further investigation, and treatment if necessary.
Unfortunately, the reality is that provision of these services is very patchy in the UK, and in many areas children receive no vision screening at all.
A sight test is a much more comprehensive check than vision screening, because it includes a check to see whether glasses or contact lenses are necessary, and an examination of ocular health. Everyone should have a sight test every two years, or more often if your optometrist recommends it, and all children are entitled to NHS-funded sight tests up to the age of 16."