The rather vague nature of the symptoms associated with Visual Stress makes it difficult to assess the prevalence of the condition. In several studies , children in primary schools were individually shown a passage of text covered in turn by a variety of coloured overlays, including grey or clear overlays for comparison. About 20% of the children found one or other of the colours improved the clarity of the text. They continued to use an overlay of that colour without prompting for more than three months. They read more quickly with their overlay, both before and after they had become accustomed to its use.


The most common symptoms associated with Visual Stress syndrome are:


  • glare from the page
  • headaches when reading
  • sore eyes when reading
  • movement/blurring of print
  • The most common signs are:
  • rubbing eyes
  • excessive blinking
  • poor concentration
  • inefficient reading
  • difficulty in keeping place


Before commencing colour sensitivity screening, it is important to confirm that the patient has had a recent eye examination by an optometrist. Many optometrists take a special interest in reading difficulties and will be able to perform additional tests to rule out an ocular cause of the problem. If no ocular cause of the symptoms is found, screening for colour sensitivity should be performed.


ReadEZ has been designed to be used by teachers, educational psychologists, optometrists, orthoptists and others with an interest in this area. The program is simple to set up and use and has been shown to produce reliable results.


However, the program must be viewed as a tool, and like all tools it must be used in the correct manner in order to produce accurate results. You are strongly advised to read through this manual carefully before attempting to use the program.


For some, the effects of colour are dramatic, for others they are slight, for others there may be a positive placebo effect and for many there are no benefits. Some will use a coloured overlay or tinted spectacles throughout their lives while others seem to “grow out” of the need for colour.


While prescribing a coloured overlay or spectacles when there is no clear benefit is unlikely to be inherently detrimental, the patient/client may be disadvantaged if other forms of assessment and management are delayed as a result. Colour sensitivity screening should therefore be viewed as part of the assessment of individuals with reading problems.