Background
The use of colour in helping people with reading difficulties was first mentioned by Critchley in 1964, but gained ground in the early 1980s following reports from Olive Mears in New Zealand and Helen Irlen in the USA. All of these authors reported cases where individuals who reported symptoms of eyestrain, headaches, and perceptual distortions when reading had their symptoms lessened or relieved by using coloured lenses, coloured overlays, or by printing text on coloured paper. This group of symptoms or syndrome later became known as Meares-Irlen Syndrome. In the late 1980s Professor Arnold Wilkins invented an instrument, the Intuitive Colorimeter, which facilitated the assessment of the precise colour to help different individuals, and this in turn allowed a randomised double masked placebo controlled trial sponsored by the Medical Research Council (MRC) to take place. This research showed that the use of individually prescribed precision tinted spectacle lenses in Mears-Irlen syndrome did indeed work. Later work has demonstrated these lenses may also help certain individuals who suffer from migraine, photosensitive epilepsy, autism, and multiple sclerosis.
What is Visual Stress?
Visual stress is a condition relating to reading difficulties, eye strain and headaches when reading. This condition may affect both adults and children. The condition is related to light sensitivity and can produce distortions on the printed page such as blurring of print; movement of words and letters; fading of areas of print and the apparent appearance of patterns within the text. Many people experience distortions of this nature when viewing striped patterns, or ironing a stripy shirt, but in sensitive individuals these distortions are induced by print.
Is This Dyslexia?
No. Visual stress can co exist with dyslexia, and individuals with dyslexia will find reading even more difficult if they also suffer from visual stress. The condition can affect people who are able readers, and research by Prof. Wilkins and others estimates that as many as 20% of individuals are affected to some extent and up to 5% of the population are severely affected.
How is the condition treated?
If an individual suffers from symptoms of visual stress such as:
- words moving on the page;
- getting headaches when reading;
- complaining of the page being too bright and the words blurring;
- eye ache or eyestrain when reading;
The first thing we recommend is a full eye examination with particular emphasis on how well the eyes work together.
After any appropriate spectacles or exercises have been prescribed, and if the symptoms are still present, then an assessment using Intuitive Overlays is carried out. This consists of allowing the individual to view print (usually random letters arranged with similar spacing to normal text) through acetate sheets of various different colours. Their response to the different colours is recorded, and through a process of elimination the best colour or combination of colours is determined.
Coloured Overlays and Tinted Lenses |
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Acetate sheets of this colour are then prescribed for use when reading, and if the individual finds these of benefit over a four to six week period an appointment is arranged to carry out an assessment with the Intuitive Colorimeter. With children we ask for parents and teachers to monitor the child’s reading speed and comprehension both with and without the overlay, and also how frequently they use the filter when reading - without being reminded. |
Intuitive Colorimetry
The Intuitive Colorimeter is an instrument which allows text to be viewed under different coloured light sources. The hue (colour), saturation (how densely coloured) and brightness can be altered by tiny increments until a precise shade is found which helps the individual by minimising or eliminating their symptoms. The instrument is then used to make repeated measurements, and in individuals with this condition a unique combination of hue, saturation and brightness is found.
Trial coloured lenses are then used to match the chosen colour, and rate of reading tests carried out to confirm the findings. Coloured spectacles, either with or without a prescription lens, can then be ordered. |
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The Intuitive Colorimeter |
How much does it cost?
The assessment of visual stress and the relief of symptoms using both coloured overlays and the intuitive colorimeter are outside the remit of a standard NHS sight test. In a recent reply to a parliamentary question on this issue the government indicated that it was up to individual Education Authorities or Primary Care Trusts (PCTs) to consider funding the provision of this service. In our experience to date, such funding is not usually forthcoming and therefore the service has to be funded privately. Where possible an initial overlay assessment will be carried out during the NHS sight test (time permitting), but in many circumstances further testing is required.
The cost of an examination including overlay assessment is £25, each A4 overlay is £5, and an Intuitive Colorimetry assessment is £40. The cost of tinted lenses starts at around £60 for plano tinted lenses and costs vary for prescription lenses depending on whether NHS vouchers can be used. A full discussion of likely costs will take place before any individual is committed to any fees. If you require further information please contact the practice team.
Other Useful Websites:
The Institute of Optometry www.ioo.org.uk
Cerium Visual Technologies www.ceriumvistech.co.uk |
