What is Visual Stress?

Visual Stress also known as Meares-Irlen Syndrome and sometimes Irlen Syndrome, is a type of light and glare sensitivity which affects around 40-50% of Dyslexics (although this number can vary), and causes words to move around on the page. The sentences when alternating with the white spacing mimic a striped pattern. At certain spatial frequencies, this makes the brain very sensitive resulting in visual disturbances which make reading extremely stressful.

There are lots of other symptoms; blurred vision, tired eyes, headaches, swirly patterns on the page, letter reversals, colours and shapes. It’s therefore a visual and perceptual disturbance, although we don’t want to get into a debate here on the difference between Vision and Perception.


If someone has difficulty with reading whereby there is a visual disturbance as described above, then they could have Visual Stress or Meares-Irlen.

Whatever the symptoms are, the consequence of this is a slower reading speed and lower literacy attainment. There are so many cases where this undetected condition has led to a lifetimes worth of heartache and feeling of helplessness.


In fact it’s not even linked necessarily to Dyslexia and many sufferers who have it are not Dyslexic. It must be emphasised, that Visual Stress or Meares-Irlen Syndrome and Dyslexia are two distinct conditions. Some studies suggest this incidence of Visual Stress / Meares-Irlen Syndrome in the general population is around 1 in 3 which means schools CANNOT and SHOULD NOT ignore it if they feel a pupil or student is not reading as well as they should.

What causes Visual Stress? The most popular theory for Visual Stress could be the Visual Cortex Hyperexcitability Theory. The words on the sentence alternate with the white spacing in between lines to create striped patterns. Therefore, at certain frequencies or size of striped patterns, this triggers off a visual disturbance in some people. This then gives rise to the symptoms experienced by Meares-Irlen Syndrome and Visual Stress sufferers.

There is still a lot of research going on in this field, but this is one of the more popular theories.

There is also The Magnocellular Theory whereby the M-Cells in the visual pathway which are responsible for detecting striped patterns are not functioning as fast as they should. Please note how we mentioned above the sentences on a page creating a striped pattern. Researchers of this theory have found Blue and Yellow filter glasses to work.

We feel there is some basis in this theory as experts in the topic, but this doesn’t explain why Visual Stress sufferers need other coloured lenses/filters and overlays e.g. Mint Green and Pink.

Read123 treat Visual Stress with specially coloured filter glasses. Also known as Meares-Irlen Syndrome, it has been known to co-exist with Dyslexia, Migraine and Autism in a number of cases. Visual Stress is managed with colour therapy using coloured overlays and coloured filter lenses. Coloured filters can be non prescription or prescription. The colour in the overlay or lenses helps manage the symptoms. Read123 use 31 specialised filter colours in their Visual Stress glasses with our own unique codes. The choice of colour is purely individual and there is no way to predict which colour will work for any one person. The filter colour required in the Visual Stress glasses may even be a customised bespoke filter which Read123 can produce for our clients at an affordable price.

Dyslexics who suffer from Visual Stress / Meares-Irlen Syndrome can be tested by qualified persons who understand the testing procedure.

Once tested and an appropriate colour has been chosen, this reduces the symptoms of Visual Stress resulting in an INSTANT improved reading speed. We have found an improvement of 70% in some cases which is extraordinary.

Visual Stress or Meares-Irlen Syndrome sufferers should be tested every 6-12 months as the colour of the overlay and filter lenses can change.