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Coloured Overlays

Coloured Overlays

Scientific research has shown that the use of coloured filters on spectacles or coloured overlays laid over text can help some children and adults to read better.

The coloured overlays help to reduce the perceptual distortions of text which can sometimes be reported. This enables more fluent reading with less discomfort and fewer headaches.

Some symptoms which can often be described are:

  • Eye strain or headaches when reading
  • Words moving or being blurry
  • Poor concentration
  • Problems associated with glare from the page

A coloured overlay assessment is carried out only after a full eye examination and if symptoms are still present after the appropriate spectacles or exercises have been prescribed.

This consists of allowing the individual to view text through different coloured acetates. Their response is then recorded to the different colours, and through a process of elimination, the best colour or combination is determined.

Suffer from Visual Stress?

...our unique precision coloured lenses can help with reading difficulties

What is Visual Stress?

Visual Stress and Photosensitive Migraine

Simply explained. Visual Stress (Meares-lrlen syndrome) is a sensitivity to visual patterns, particularly stripes.

In some individuals this condition can cause visual perceptual problems which interfere with reading. The symptoms can occur despite normal vision.

One current scientific explanation is that the perceptual problems are due to a hyperactivation of the visual cortex of the brain, particularly in more anterior visual areas, which is reduced by precise individual colour.

The Symptoms of Visual Stress

All or some of the following may be present

  • Movement of the printed text.
  • Blurring of print
  • Letters changing size or shape
  • Patterns in the print (Sometimes described as rivers or    worms)
  • Halos of colour surrounding letters or words
  • Tiring easily whilst reading
  • Headaches or visual discomfort
  • Red, sore, watery eyes


The Signs of Visual Stress

  • Moves closer to or further away from the book
  • Moves book around on the desk
  • Fidgets continuously
  • Using finger as a marker on the page
  • Skips words or lines.
  • Frequently re-reads the same line
  • Rubs eyes or blinks frequently when reading
  • Poor comprehension of reading content
  • Frustration and low self-esteem

Frustration and low self-esteem can occur in children who are underachieving due to visual stress. Early diagnosis of the problem is essential. The longer it takes to identify and remedy visual stress, the greater the loss of confidence that can result.

Visual Stress and Photosensitive Migraine

Migraine attacks have many triggers, including stress, particular foods, and hormones. About 40% of migraine attacks may be visually-induced by flickering light, patterns or reading. These attacks may be helped by precision tinted lenses.

Research in the US undertaken recently by a team of neuro-scientists, using brain imaging, has shown that a suppression of hyper-excitability in the visual cortex occurs in migraineurs when individually selected precision tinted lenses are worn.

The lenses for the study were selected using the Intuitive Colorimeter. Symptoms of other neurological conditions such as Autism, MS, ME and Parkinsons have been shown to reduce with the application of a precise colour.

Is this Dyslexia?

‘Dyslexia' is a term used to refer to reading problems that are not due to poor teaching. Dyslexia is often associated with spelling difficulty. 

Visual Stress is NOT the same as dyslexia but is more common in those who are dyslexic. People who fail to read because of visual stress are frequently mis-diagnosed as dyslexic. For this reason it is important that the existence of visual stress is identified at an early stage. Once the visual stress has been treated, the remaining problems are more easily dealt with.

Visual stress can occur in non-dyslexic individuals. Symptoms may become more apparent when intensive reading is necessary, as when studying for exams.

A Solution

Visual Stress can be reduced by the use of coloured filters: a coloured overlay placed over text or coloured tenses worn in spectacles. The reduction occurs only when the colour is selected to suit the individual. The selection of lenses is best undertaken with the aid of the Intuitive Colorimeter.

Coloured overlays are widely used by teachers in schools throughout the UK. If an overlay proves useful it is likely that precision tinted lenses will also be beneficial. Lenses can be used for writing as well as reading. They can also be worn to reduce glare. It is important to note that the most effective coloured overlay is unlikely to have the same colour as the optimal precision lenses.

A full eye examination is necessary before prescribing precision tinted lenses. This procedure is best undertaken by an optometrist who also specializes in colorimetry. Appropriately tinted tenses frequently result in reading that is more fluent and comfortable. Some lens wearers enjoy significant improvement in both reading rate and accuracy.

The degree of improvement differs: some individuals experience improvements in reading age of one - two years within a few weeks of acquiring the lenses. In others the lenses may offer greater comfort when reading, but the reading improvement may be less dramatic because of other reading difficulty.

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