and Irlen Tinted Filter Lenses
Have you heard of tinted lenses as a remedy for
reading disabilities, rapid fatigue when reading, headaches, sore eyes and
poor depth perception? For more than fifteen years this new technique has
been available in Australia with some very exciting results. The technique
uses precisely prescribed tinted filter lenses to correct perceptual disorders
which often cause reading disabilities.
The technique was developed in the early 1980s by Professor Helen Irlen,
a Californian psychologist. She was the director of a research project,
investigating adult reading disabilities at the University of California.
She was talking with a group of adults who had severe reading difficulties.
Their comments prompted her to ask them what the reading page looked like
to them and she was astonished by some of the comments they made. Around
her she was hearing people saying, "That's what I see too! When I tell my
family, they laugh at me." They described how the letters on the page seemed
to move around, how the white page strained their eyes, how they saw streaks
of white on the page, how the print went blurry, how they saw ghosting of
Since 1986 over 80,000 children and adults world wide have been prescribed
Irlen lenses. Most have been people with reading disabilities ranging from
severe to mild, while others suffered from chronic glare headaches and Chronic
Fatigue Syndrome. Some have visual disorders and reading problems resulting
from head injuries due to an accident, or to central nervous system infections
and some have Autism Spectrum Disorder. The technique is seen as the biggest
breakthrough in assisting individuals with learning disabilities for more
than twenty years.
It must be stressed that this method does not help every person with reading
disabilities. Recent research indicates that approximately 60% of individuals,
both children and adults, who find reading difficult, fatiguing or stressful,
can be helped considerably with Irlen tinted filter lenses. When one considers
that recent research on adult literacy in Australia, shows that between
15% and 20% of all adults, or more than 1.5 million adults, are functionally
illiterate, then the number of people who might benefit from the lenses
is apparent. All the more reason why children at school, especially in primary
school, should be screened if they are struggling with reading skills or
they avoid reading consistently.
Helen Irlen called this disorder "Scotopic Sensitivity". Essentially it
is a specific sensitivity of the visual system to certain frequencies within
the white light spectrum. This appears to be an inherited disability which
causes rapid fatigue of the visual system resulting in a range of symptoms,
most of which interfere with effective and efficient reading performance.
It should be stressed that these symptoms persist despite thorough optometric
assessment and the wearing of prescription lenses.
However, prior to assessing a client for Irlen lenses, a recent optometric
assessment is recommended. This is to ensure that any refractive or astigmatic
problems have been corrected. The individualised Irlen tint can only be
added to existing prescription lenses if they have been manufactured according
to our precise specifications. Often, some optometrists prescribe low-powered
stress lenses for children with reading difficulties. Sometimes this is
quite helpful, but it rarely solves a serious reading difficulty.
There are still many "sceptics" within the community. When the lenses were
first used, there was very little scientific evidence to support the theory.
However there are now over a hundred research publications on Irlen tinted
lenses, including research from Harvard Medical School and the Canadian
A recent breakthrough in research on dyslexia at Harvard University clearly
links disorders in a person's visual perception as a major cause. A team
of neuroscientists, lead by Dr Margaret Livingstone has reported research
in the prestigious research journal "Proceedings of the American Academy
of Sciences". Their findings show that Visual dyslexia is the result of
the failure of the visual perceptual system's neuro-circuits to keep proper
timing. They also reported that coloured filters can correct this imbalance
and so reduce the effect of dyslexia, such as chronic loss of place, reversing
words, blurred vision, movement of the print and rapid fatigue when reading.
Dr Drake Duane, an authority on dyslexia and learning disorders at the Arizona
State University, states that this research provides "convincing evidence
that the nervous system of those who are dyslexic are atypical and provides
theoretical support for one treatment of dyslexia through the use of coloured
filters for reading".
Dr Galaburda, Director of the Dyslexia Neuro-anatomical Centre at Beth Israel
Hospital in Boston, views this research breakthrough as indicating that
the visual system consists of two major neural pathways. "One of these pathways,
the magnocellular system, is composed of large cells that carry out fast
processes and is used for seeing motion, stereoscopic vision, depth perception,
low contrast and locating objects in space. The second pathway, the parvocellular
system, is composed of smaller cells that carry out slower processes. It
specialises in colour, detailed forms, high contrast and stationary images."
Dr Galaburda explains that a neurological timing imbalance or 'sluggishness'
in the timing between these two systems leads to visual dyslexia.
This is because of the visual perceptual demands of the reading process,
usually in situations of high contrast of black print on white paper. It
also accounts for why a significant number of people with reading difficulties
have poor depth perception and are clumsy. In essence, the disturbed synchronisation
of the two visual perceptual pathways leads to these perceptual disorders.
Autopsies conducted by Dr Galaburda on the brains of ten deceased people,
five known dyslexics and five normal readers, showed distinct anatomical
cell differences (in size) when the parvocellular and magnocellular cells
Professor Mary Williams, University of New Orleans, has completed research
which indicates that the 'sluggish' timing or lack of synchronisation of
these two visual pathways in dyslexic children is corrected with the use
of coloured filters.
Dr Solman, a research psychologist and Professor Dain, a research optometrist,
both at the University of New South Wales, recently published research that
also provides strong evidence that contrast sensitivity of white to black
when reading print on white paper, was a significant factor in creating
reading perceptual disorders. Also coloured filters that were specifically
prescribed for particular reading disabled children, dramatically reduced
sensitivity and improved reading.
From this recent research evidence, there can no longer be any doubt that
Helen Irlen was correct. Carefully and precisely prescribed spectrally modified,
Irlen tinted filters substantially reduce perceptual disorders for those
children and adults who have this visual perceptual dysfunction she calls
"Scotopic Sensitivity / Irlen Syndrome".