See Also Visual Stress or Irlen Syndrome FAQ
What is Visual Stress?
Visual Stress is also known as Meares-Irlen, named after the two researchers who first discovered the connection between white page "glare" and reading difficulties in the early 1980s. It is also called Scotopic Sensitivity Syndrome, although scientifically it has now been shown that this is not a very accurate term, as it refers to an area of the visual system that is not actually affected by the condition. Visual stress is the name most commonly used in the UK.
There is as yet no proven scientific explanation for Visual Stress although many experts agree that the problem is visual-perceptual in nature, most probably originating in the visual cortex of the brain, arising from a deficiency in one of the visual pathways. Because it is perceptual, rather than visual in nature, it is not corrected by prescription glasses, and it cannot be detected by standard visual, educational or medical tests.
How do you know if you have Visual Stress?
Symptoms of Visual Stress vary , but can include headaches and migraines (especially when working at the computer), eyestrain, and words or letters appearing to "jump" or move on the page. People who have Visual Stress see the page differently because of distortions of the print or white background.
In general, somebody with Visual Stress may
Some, or all, or the following can be noted while reading. Sufferers may:
Visual Stress typically causes the following distortions of print, although not all of the following will necessarily be experienced by one person:
Does Visual Stress go away?
Generally, no; although there are cases reported where the contrary has been the case. Sensitivity does seem to change though, especially in a changed response to coloured filters. Somebody who has found a particular colour most beneficial may find that this preference changes and a different tint will be more helpful.
What can be done?
People with Visual Stress can read with much greater ease if they cover a print with a specially treated coloured overlay. Screening can help to identify which colour is most beneficial. Crossbow Education supply convenient reading rulers and the larger A4 size coloured overlays in ten colours that have been carefully selected to cover the full spectrum in different combinations. Crossbow also supply the Visual Stress Assessment pack for thorough screening of individual colour preferences. For any optical difficulties, it is important that an optometrist is also consulted to ensure that there are no underlying medical or ophthalmic conditions. Some optometrists prescribe coloured lenses, and have specialist equipment to test for colour preference. It is often found that lenses of a different colour from the overlays are needed. A list of specialist optometrists and Irlen centres can be found on