Visual stress is a sensitivity to visual patterns, especially stripes. This can interfere with reading even if there are no other vision problems. Typically print will appear to move about on the page, print may blur, letters will appear to change size or shape, or patterns may appear within the text.
Coloured filters can help, used either as an overlay (a transparent coloured plastic sheet) which is placed over the text when reading, or as coloured glasses, which are much more convenient, and can be worn for reading, writing, computer use and board work at school or college.
Coloured overlays are used by many teachers in schools, and you, or your child, may be referred to the Practice for further examination. Overlay testing is carried out at the Practice particularly with younger children; the coloured sheet which most improves reading fluency is selected from a set of ten, and an overlay of the selected colour will be given to you to take home for trial use for a few weeks. If after that time the overlay is still helpful a further assessment for coloured glasses will be carried out.
Finding the most effective colour for these glasses is found using an instrument called a Colorimeter, which can produce light of many different colours and degrees of brightness (several thousand combinations are possible), so that the exact shade which is most helpful can be found.
A full eye examination is recommended before colour testing to identify any other visual problems which may also be present, and ensure that we can find the most effective combination of colour and glasses.
If colour is not helpful further investigation, possibly involving Vision Therapy may be suggested.