Some people experience visual discomfort and perceptual distortions when they look at certain materials, particularly text. These include blurring, movement of letters, haloes of colour around text, shadowy lines and flickering which may interfere with reading. Visual stress (also known as called Mearles-Irlen Syndrome or Scotopic Sensitivity Syndrome) is estimated to be present in 20% of the general population and tends to be higher in the dyslexic population.
Perceptual distortions can sometimes be reduced or eliminated by using coloured overlays and tinted glasses. They enable people to read more fluently and with less discomfort and fewer headaches. Migraine sufferers whose attacks are visually induced by flickering light, patterns or reading may also be helped with coloured overlays and coloured spectacle lenses.
It should be suspected in individuals who have difficulties in learning to read, if there are reports of letters or words appearing to move or reporting glare from the white paper.
Glare from the page
Headaches when reading
Sore eyes when reading
Movement/blurring of print
Rubbing eyes
Excessive blinking
Poor concentration
Inefficient reading
Difficulty in keeping place
Poor comprehension
Coloured Overlays are sheets of transparent or translucent coloured plastic that can be placed over a page or a book in order to colour the text and/or background beneath without interfering with the clarity. The appropriate choice of colour for reducing the distortion varies from person to person. Sometimes the colour gives an improvement in reading fluency and helps a person to read longer and more comfortably, without eye strain. The overlays are used for a short period to see if the perceptual distortion improves. Some people use the overlays for several months and then stop using them. Sometimes this is because reading without the overlays has improved or the visual problems still exist, but the choice of colour is no longer effective. The overlay selection should then be repeated. Some people prefer to have text printed on coloured paper. If the overlays have been used over a period of time and are found to be beneficial glasses with coloured tints may be considered.
Precision Tinted Lenses are a more convenient method of using colour when writing or copying from the board, for VDU work or for patients who are particularly light sensitive. Coloured glasses can be used for every task for which the individual perceives a benefit. The appropriate colour for use in glasses is not the same as that in overlays. The colour of the lenses can only be assessed by optometrists who use the Intuitive Colorimeter. The Colorimeter offers several thousands of colour combinations and is assessed specifically and precisely for each patient in terms of hue, saturation and brightness.
For more information about Intuitive Colorimetry visit Cerium Tech
For simulations of visual stress visit Opticalm
For video of actress Kara Tointon learning about her visual stress and being prescribed her Precision Tinted lenses visit this YouTube video
To book a private consultation or for more information please telephone the practice on the number above. You will also find it beneficial to read the following document on our Visual Stress Assessment Procedure