Visual stress can contribute to reading difficulties in many children and adults.

Visual stress is when the visual cortex (the visual processing area of the brain) is over stimulated due to sensitivity to visual patterns, for example lines of black text on white paper.

Symptoms of visual stress include:

  • Blurring of print
  • Letters and words appearing as if they are moving
  • Discomfort when reading
  • Glare from a white page
  • Patterns in the print
  • In some cases migraines

Signs of visual stress include:

  • Skipping words or lines
  • Re-reading the same line frequently
  • Moving the book around the desk
  • Moving closer or further away from the book
  • Poor comprehension of reading content
Colorimetry Test

Visual stress can be a major part of the problem in poor readers even with those who are diagnosed 'dyslexic'. If visual stress can be identified and treated, any remaining issues can be easier to manage.

The first thing we would recommend is a full eye examination. It may be that if there are any other underlying issues, a more thorough examination will be required.

If symptoms continue after appropriate spectacles or vision training exercises have been prescribed then our next step would be to carry out an overlay assessment. (Vision training is not covered by the NHS unless provided via a hospital.)

This involves the individual viewing text through various coloured acetate sheets. The response to each colour is recorded and the best colour or colour combination is determined.

If, after a trial period, the individual is working well with the overlay and finding it beneficial then the next stage would be a diagnostic colorimetry assessment.

This measures the individual's response to text that is viewed under different highly controlled coloured light conditions. The appropriate coloured tint can be diagnosed and coloured spectacles ordered.

The cost of the coloured overlay and colorimetry assessment are not covered by the NHS.

The cost for the coloured overlay appointment is £45 including provision of an overlay and the colorimetry assessment is £60. The cost of precision tinted lenses starts around £200.