People with visual stress may experience one or several of the following:
- Blurred letters or words which go out of focus.
- Letters which move or present with back to front appearance or shimmering or shaking.
- Headaches from reading.
- Words or letters which break into two and appear as double.
- Find it easier to read large, widely spaced print, than small and crowded.
- Difficulty with tracking across the page.
- Upset by glare on the page or oversensitive to bright lights.
In some cases any of these symptoms can significantly affect reading ability. It can also make reading very tiring. Of course a child will not necessarily recognise what they see as a problem, as this is how they always see text.
If a child complains of a least one of these problems or has difficulty at school, they should be referred to an optometrist or orthoptist with expertise in this particular field. Many dyslexic people are sensitive to the glare of white backgrounds on a page, white board or computer screen. This can make the reading of text much harder.
- The use of cream or pastel coloured backgrounds can mitigate this difficulty as can coloured filters either as an overlay or as tinted reading glasses. – People with reading difficulties sometimes have a weakness in eye co-ordination or focussing and an specialist practitioner might recommend treating this with eye exercises or glasses. If these problems are present, they should be detected and treated before coloured filters are prescribed.
- Research in the UK and in Australia shows that people who need coloured filters, who are said to have visual stress, need to have exactly the right colour. Many optometrists and orthoptists use a special instrument, the Intuitive Colorimeter, to determine the exact colour that is necessary for coloured glasses.
- The choice of colour of text on white backgrounds can also affect clarity e.g. using red on a whiteboard can render the text almost invisible for some dyslexic students. For information on dyslexia friendly text see Dyslexia Style Guide.
An exmaple of visual stress:
Local Optician Services:
- Leslie Warren- Sevenoaks and Bexleyheath
- Arthur Hayes Optician- Tunbridge Wells
- Wilkinsons- Tonbridge
The Institute of Optometry.
Runs courses for teachers and eyecare practitioners about vision and reading difficulties and has a clinic for people with reading problems.
Tel: 020 7407 4183
Fax: 020 7403 8007
Institute of Optometry Sales Ltd.
Cerium Visual Technologies.
List of optometrists in UK who have a Wilkins Intuitive Colorimeter and can prescribe Precision Tinted. Also supplier of coloured overlays.
Cantor & Nissel.
ChromaGen Haploscopic lenses are a type of colour based system for spectacles or contact lenses.
Licensed practitioners round the UK.
Tel: 01280 702 002
The Irlen Centre. Tinted lenses.
Computer aids for visual stress.
- Monitor ovelays are available in different shades and sizes which are held onto the screen by static.
- Claro View: software offering a simple way of changing the background colour of the screen, with a wide range of different colours.
- Claro Screen Ruler suite: software to help with visual tracking and focusing on-screen. The Screen Ruler allows part of the screen to be highlighted or underlined depending on the user’s preference. It provides a strip or ruler across the screen, which can have the contrast changed and have the background coloured or greyed out.
Dyslexia and Vision. Bruce J.W. Evans. Wiley
Visual Factors in Reading. Edited by Piers Cornelisson & Chris Singleton. Wiley
Tel: 01243 843 294
Fax: 01243 843 303