Visual Stress - Colourimetry

Who Suffers from Visual Stress?

The causes of visual stress are still unknown with no scientific explanation for the symptoms, however it is commonly agreed to be a visual-perceptual problem believed to stem from the visual cortex of the brain.

It is estimated that 1 in 5 people with dyslexia experience visual stress, but although they may co-exist, visual stress and dyslexia are different conditions.

Visual Stress is found to exist in many conditions including:

• Dyslexia
• Dyspraxia
• Photosensitive Migraine
• Photosensitive Epilepsy
• Autism
• ADHD

The term Meares-Irlen syndrome refers to a form of Visual Stress; it is the collection of symptoms or signs of visual fatigue when reading that are reduced when a colour is used. (Other terms include Irlen syndrome, Scotopic Sensitivity Syndrome SSS or Pattern Glare).

Signs and Symptoms

Symptoms

• Headaches
• Eyestrain
• Movement of letters / print
• Letters changing shape / size
• Illusions of colour on the page
• Letters or lines fading in depth across the page
• Lines jumping on the page
• Blurring of the text

Signs

• Moving closer or away from the page
• Restlessness while reading
• Using a finger or ruler as a marker
• Skipping words and lines
• Rubbing of eyes
• Blinking excessively

What do we do?

Using Colour Overlays

The treatment for visual stress is still debated. Research has come up with mixed results, with divided opinions on the benefits of using colour overlays on text. Presently some scientists believe colour overlays help those who experience visual stress. Interestingly, one study in 2005 found that 37.5% of children with dyslexia were affected by visual stress, whilst 25% of non dyslexic children were affected by it. There are those who believe dyslexia and visual stress are related in some ways.

According to a 1999 study by Evans et al, 80% of people who used coloured overlays found benefits from using them when reading. Another study in 2001 found that children with dyslexia who were allowed to pick their own coloured overlay saw a reading speed increase of 25%.

This has been argued however in a recent 2015 study whereby the author discredits the theory that dyslexia is caused by visual problems, meaning that coloured overlays will not reduce the symptoms. They suggest there was very little difference in performance of visual tests between dyslexic and non-dyslexic children.

Despite this, many people and children make use of coloured overlays when experiencing visual stress.

Different Coloured Overlays

It is commonly believed that a particular colour, hue and saturation will work best for each individual, i.e. an overlay that works for one person might not work as effectively for another. However, there appears to be no agreement on which coloured overlay works best as a whole. In conclusion, coloured overlay helps the symptoms of visual stress, the person affected is the best person to judge this. If no difference is experienced, they do not need to continue using them.

Sources: Irlen H. (1997). Reading problems and Irlen coloured lenses. Dyslexia Rev. Spring 4–7, Evans,B. J. W.,Patel,R.,Wilkins,A. J.,Lightstone,A., Eperjesi,F.,Speedwell,L. and Duffy,J. (1999) A review of the management of 323 consecutive patients seen in a specific learning difficulties clinic.

What we do

You or your child will be asked to view a page of random text whilst being shown a comparison of that text through different coloured overlays.  Colours which make the reading easier and more comfortable will be short-listed then the preferred colour determined. This test is called the Wilkins Rate of Reading Assessment.

An acetate sheet of the preferred colour will be issued, for a small charge, and you will be asked to use this when reading over the next 4 weeks.  If the overlay is of genuine benefit then continue to use it when reading, helping to rule out the placebo effect.

There are different management techniques used for the symptoms of visual stress. At Complete Eyecare our onus is on the comfort in reading and learning that colour overlays produce. There are more refined techniques available which can find the exact depth and hue necessary for correction, however for many families this can be quite costly and sometimes outside of the range of what is affordable.

We have been able to produce high quality tints best matching those of the 12 colour overlays we use for of visual stress testing. This allows us to manufacture prescription and non prescription lenses encorperating the correct tint so that an overlay need not be used. For many, an overlay sheet can be limiting, when many read on tablets and computer screens rather than on paper.

These colour tints can be manufactured for as little as £50.00*.

* Costs shown would be an added cost to the frame and lens prices shown in practice