Irlen Syndrome, or Scotopic Sensitivity Syndrome, was first identified by Educational Psychologist Helen Irlen while she was working with adult learners in the early 1980's. Until described in her book, Reading by the Colors (Avery Press, 1991), there was no explanation or treatment for this perceptual disorder. Many people with this disorder were misdiagnosed as dyslexic or slow learners. In 1991, Dr. Margaret S. Livingstone of Harvard Medical School published research which offered a medical explanation for this disorder.
Individuals with Irlen Syndrome perceive the printed page and/or their environment differently. If they are severely affected, they must constantly make adaptations or compensate. Individuals are often unaware of the extra energy and effort they are putting into reading and perception.
Reading may be slow and inefficient, or there may be poor comprehension, strain, or fatigue. Irlen Syndrome can also affect attention span, listening, energy level, motivation, work production, and mental health.
People with Irlen Syndrome are often seen
as underachievers or as having behavioral, attitudinal, or motivational
problems. Irlen Syndrome can also coexist with other learning
problems, such as attention deficit disorder, dyslexia, or autism.
Treatment for Irlen Syndrome may lessen many of the symptoms of
The following is a short excerpt from the Irlen Survey form, used to determine if screening for Irlen Syndrome is advisable. The full version (4 pages) can be downloaded here: Word Document PDF File
If an individual answers yes to 3 or more of the following questions, there is a good chance that they are affected by Irlen Syndrome, and they should be tested by a qualified Irlen Screener. In the screening, he/she will find out for certain if they are affected, determine their level of severity, and learn about treatment. More information about screening can be found at the bottom of this page.
Other signs of Irlen Syndrome include:
To see what the printed page can look like to someone with Irlen Syndrome, click here.
Although the exact cause of Irlen Syndrome has yet to be established, it has been shown to be a visual-perceptual problem, most likely originating either in the retina of the eye or in visual cortex in the brain. The following is a hypothetical explanation, based on current research into this syndrome.
In the visual system, there are two separate visual processing pathways, the Magnocellular, or Fast, and the Parvocellular, or Slow. The Fast pathway does not see colours, and is responsible for discerning movement, depth, and high contrast images. The Slow pathway determines colour, fine details and resolves low contrast images. The Fast pathway is also responsible for inhibiting the slow pathway when the eyes are moved, so that the image of what was previously being looked at does not persist. It appears that in people with Irlen Syndrome, the Fast pathway is disabled to some extent. This seems to affect the ability of the Fast pathway to inhibit the Slow pathway, which in turn results in images persisting when the eyes are moved. As a result, the brain perceives overlapping images. In severe cases, when the brain tries to interpret these images, it perceives images that aren't there. The individual may "see" letters moving on the page, blurring, or forming strange patterns. In less severe cases, the misperceptions do not occur or may be suppressed, but the brain expends more energy in processing the images than is required by most people, resulting in headaches, eyestrain, and/or fatigue. These problems generally get worse the longer a person tries to read, or do other visually intensive activities.
Bright lights, fluorescent lights, or glossy
paper will often make the problems worse, as the extreme contrast
will increase the problem of persistent images. Irlen Syndrome
manifests itself most strongly when reading words or music, because
of the repetitive patterns on the page. When the eyes scan across
the page, the patterns of words on the page and persistent images
will jumble in a manner that is difficult for the brain to interpret
properly. In the Irlen Method, the individual is assesed with
a wide array of colour filters, singly and in combination, to
find the most suitable colour. The colour filters appear
to act by blocking some of the light which would normally activate
the Slow visual pathway, in effect taking over the inhibitory
role of the Fast pathway, and thus appear to reduce or eliminate
the persistent images. The filters stop the confusing signals
from being sent to the brain, and the individual will see the
page more normally and easily. This treatment may also be
helpful to individuals who experience other related problems,
such as faulty depth perception or night driving difficulties.
The screening for Irlen Syndrome involves challenging the visual system to determine the severity of symptoms. Then colour overlays are used to alter the contrast between the words and the page. Once the proper colour combination has been determined, overlays of that colour are placed over the page while reading. As a second step, tinted Irlen filters (lenses) are recommended for most people. Although the treatment is simple, the results are often very dramatic. The use of the colour filters will allow a person with Irlen Syndrome to see the words on the page clearly. The individual can then develop the skills necessary for efficient reading. Once the skills are in place, individuals can read for long periods without discomfort. Therefore, the affected individual can more effectively practice reading, one of the most important elements in learning how to read. This allows for quick and dramatic improvement of reading skills, and will enhance academic performance and self esteem.
For those individuals in whom Irlen syndrome
is only one layer of their disability, the Irlen filters remove
that layer of difficulty, making it easier to identify and remediate
the other difficulties. For these individuals improvement in reading
and other language skills will require intensive intervention
and progress will be slower.
Reading & Writing Consultants is now also the Irlen Centre-Alberta. We handle both Screening and Irlen Lens Assessment. For more information, phone (780) 439-8120 or e-mail firstname.lastname@example.org. We are happy to answer specific questions about Irlen Syndrome.
As numbers warrant, we travel to Alberta communities to do lens assessments and tint checks
International: To find a screener in your area, go to The Irlen Institute screeners list, where they list screeners and centers around the world.
Western Canada: We now have a web page which contains an up-to-date list of active screeners. To find one in your area, click here.
For more information on Irlen Syndrome and other reading disorders, try the following pages: