Colorimetry Assessment

Colorimetry assessment specialists

Do you suffer with Dyslexia or Visual Stress or other reading difficulties?

What is Visual Stress?

Simply explained, Visual Stress (Meares-Irlen 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 the more anterior visual areas, which is reduced by precise individual colour.

The Symptoms of Visual Stressdyslexia-low-res

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 the desk
  • Fidgets constantly
  • Uses finger as a marker on the page
  • Skips words or lines
  • Frequently re-reads the same word or 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 under-achieving 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 migraine sufferers 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 Parkinson’s 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 managed.

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 lenses worn in spectacles. The reduction occurs only when the colour is selected to suit the individual.  The selection of coloured 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 also be used for writing as well as reading.  They can also be worn to reduce glare. It is important to note that the 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 specialises in colorimetry.  Appropriate tinted lenses 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 1-2 years within a few weeks of acquiring lenses.  In others, the lenses may offer greater comfort when reading, but the improvement may be less dramatic because of other factors.


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  • Eye Examination

Every child who displays problems with reading should be referred to an optometrist for a full vision test. It is recommended that the chosen practice should also specialise in using the Intuitive Colorimeter. If a refractive prescription is required (eg for long or short sight) then this can be incorporated into the coloured lenses

  • Overlay Assessment

An assessment with overlays may already have been carried out in school. If the school does not use overlays an optometrist can also carry out this assessment.  The optometrist may suggest the patient use an overlay and return within a few weeks, noting any improvements that result.  Alternatively, in cases where the benefit from an overlay is clear, the optometrist may suggest moving directly to testing with the Intuitive Colorimeter.

  • Colorimetry Assessment

If overlays are beneficial, the optometrist may suggest Colorimetry as the next stage. This may result in the prescribing of spectacles with coloured lenses.  The colour will be more specific to each individual’s needs, much more precise than the overlay and very often a different colour to the overlay.  Coloured lenses are also much more convenient than overlays for board and computer work.

If you would like more information about any of the above, please contact one of our specialist optometrists, Alison Jarah or Sally Richards on 01278 422978 or email:

Above information provided by courtesy Cerium Technologies

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