Visual Stress & Migraine

Dyslexia is a term used to describe various specific learning difficulties that affect the ability to learn to read and spell correctly. Visual stress is not dyslexia, but can be particularly prevalent in dyslexic individuals. If visual stress is identified and colour is used to alleviate some of the symptoms, then other learning difficulties such as dyslexia are easier to cope with.

Many people with dyslexia may also suffer with visual stress and can therefore be helped by colour. Equally, there are a large percentage of children, and indeed adults, who are not identified as being dyslexic but still suffer with these symptoms. The appropriate coloured overlay or precision tinted lenses can also help this group of individuals.

As people get older and text is not such a meaningless group of words, visual stress can be less pronounced, but still there. In a lot of cases the syndrome goes undiagnosed and untreated until adult life.

The colour of the lenses can only be assessed by using the Intuitive Colorimeter, which uses a much larger range of colour combinations than the overlay assessment. This gives a much more accurate colour specific to each patient, and is usually carried out by our experienced opticians. The assessment takes about 1 to 1.5 hours.

When you wear glasses the whole of your visual field is coloured, so that you are fully adapted to that colour. The Intuitive Colorimeter takes account of this and tests in the same way, so that no other colour of light is involved. Overlays, on the other hand, only cover part of your visual field, so white light plays a big part. This colour adaptation factor means that the colour of lenses is different to the colour of overlays.

Overlays are sheets of transparent coloured plastic which are placed over the required text. They are used as a screening tool to determine if colour will be of benefit to each patient. They can alleviate some of the visual stress, making reading more comfortable. Each child will benefit from a different colour. To assess the benefit of a chosen colour, the Wilkins Rate of Reading test can be carried out.

• Moving closer to or away from a page
• Becoming restless
• Using a finger as a marker
• Skipping words and lines
• Rubbing eyes and blinking excessively
• Low self-esteem
• Lack of concentration
• Movement of print
• Blurring of print
• Letters changing shape or size
• Letters fading or becoming darker
• Patterns appearing, sometimes described as “worms” or “rivers” running through the print
• Illusions of colour, which can be blobs of colour on the page or colours surrounding letters or words
• Rapidly becoming tired
• Headache or eyestrain

Symptoms of visual stress are not always immediately obvious. Many individuals who suffer with this condition believe the discomfort they feel when reading, or the distortions they experience on the page, is “normal” and experienced by everyone. That is until someone presents them with an appropriate colour and they realise that reading can become more comfortable and even enjoyable.

Visual stress could be a result of light sensitivity, the appearance of patterns in text and glare effect. It is currently believed that visual stress is linked to too much activity in the visual cortex, the part of the brain responsible for processing vision.

If the child continues to use the overlay unprompted, or the teacher or parent reports an improvement, it has most likely been beneficial. The overlay is usually given for a trial period of approximately six weeks to rule out novelty factors. Glasses with coloured lenses can then be prescribed. These are more convenient as they can be used with board work. The tint is a much more precise shade as many more colour combinations can be used. Again, the tint will vary from person to person.

People with visual stress experience discomfort and sometimes pain on viewing specific visual patterns and colour combinations. This can affect their ability to read standard formats of printed text and can even cause migraine. Around 20% of the population experience some symptoms of visual stress. Visual stress was recognised in the 1930s and our understanding of how it works is changing and improving all the time.

• Dyslexia
• Dyspraxia
• Photosensitive migraine
• Photosensitive epilepsy
• Autism
• ADHD
• Head injuries
• Multiple sclerosis