It has been known for over twenty years that some people experience visual distortions when reading. These distortions can lead to sore, tired eyes, headaches, double vision and blurring of the text on the page, and illusions of shape, colour and motion in the text. Visual Stress varies in severity from one individual to another and affects around 15-20% of the population. People who suffer from visual stress when reading also tend to be very sensitive to fluorescent lighting and to flicker on computer monitors. This condition is sometimes known as Meares-Irlen Syndrome after its original discoverers, but is also known by other labels such as ‘visual discomfort’ and ‘scotopic sensitivity syndrome’.
Because visual stress makes the experience of reading uncomfortable it hinders children’s reading development. Even if they have mastered the basic skills of how to decode words, they will avoid spending the time reading that is required to develop reading fluency. Although visual stress can be associated with dyslexia, it is not the same as dyslexia, and the two conditions should not be confused. Most people who suffer from visual stress are not dyslexic and treatment for visual stress will not ‘cure’ dyslexia. However, for someone who is struggling to learn to read, Visual Stress will make the whole situation much worse.
Alleviation of the problem
The symptoms of visual stress can be reduced by enlarging text or by using a reading mask which covers the lines of text above and below the line being read. Crossbow Education (www.crossboweducation.com) produce Reading Rulers which provide such a mask with a coloured insert. The use of coloured overlays or tinted lenses is the most commonly successful way to treat Visual Stress. Using coloured paper rather than white pa-per is often more comfortable. However, the most effective colour varies from one individual to another.
There are two computer products that are helpful when working with a computer:
- Readable (www.dyslexic.com) lets you choose the screen colour that suits you, as well as the font, size and spacing that is most comfortable
- The Textic Toolbar (www.textic.com) is an add-on that enables the colour and fonts of web pages and other Windows applications to be modified
Identification
Identifying Visual Stress can be difficult, particularly in children who are often unaware that what they are experiencing is any different from other people. It would be advisable to consider screening for Visual Stress any child who is struggling with literacy. Indeed, if any of the following symptoms occur after the age of seven years, a test for binocular instability or light sensitivity would be a good idea:
- Reversals of single letters, letters within words, words within sentences, when
- Reversals of single numbers and number order
- Omission or insertion of words
- Losing the place when reading, especially when moving from one line to the next.
- Using a finger or marker to locate the target words when reading
Overlay testing kits are available from Cerium Visual Technologies, Cerium Technology Park, Tenterden, Kent TN30 7DE Tel: 01580 765211 Email: ceriumgrp@aol.com. Cerium also produce coloured overlays and will supply a list of high street optometrists and hospital eye clinics who provide Colorimeter testing and coloured lenses if needed.
Lucid Software have recently produced a computerised, objective screening system called ViSS (Visual Stress Screener). This consists of a word search game that children do under two conditions, one which is visually stressful and one which is normal.
A Health Warning!
Whenever such a problem is suspected or detected it is important that the individual concerned undergoes a full binocular vision check with an optometrist to see if there are any other eye problems which could be causing the condition. The British Association of Behavioural Optometrists maintain a register of optometrists trained in the investigation of visual factors affecting reading http://www.babo.co.uk/default.htm
For more information visit www.visual-stress.com
Signs of vision problems
This list is not necessarily comprehensive: ’symptoms’ indicate that further investigation should take place.
- Blurring of words when reading
- Working distance close when writing or reading
- Blinks or rubs eyes a lot
- Covers one eye when reading
- Moves head when reading
- Reading accuracy and speed below chronological age
- Loses place or line when reading
- Misses out words or letters when reading
- Often has to use a finger as a marker to keep place
- Headaches and/or aching eyes
- Comprehension exercises difficult
- Difficulties with copying from the blackboard or a book
- Poor visual memory
- Poor or variable handwriting, often slow
- Loss of concentration, poor attention span
- Gets rapidly tired at school and is often exhausted at the end of a school day
- Mixes numbers on Maths
- Reverses letters and numbers
- Mirror writing
- Poor co-ordination or history of coordination problems
- Confuses right and left past the age of 7 (and sometimes up and down)
- Poor posture when working
- Poor at ball skills and team games
- Homework takes longer than it should