Colorimetry & Visual Stress
Discover how colour can alleviate visual discomfort and help with Dyslexia and Meares-Irlen Syndrome.
Visual stress is a term used to describe visual discomfort and perceptual distortions in the printed text, suffered by many people who struggle to read. The condition is estimated to be present in about 40 % of poor readers and in 20 % of the general population in varying degrees.
Coloured overlays can improve reading speed and accuracy. They can enable longer periods of reading free of discomfort. When they do, it is an indication that the individual may benefit from Precision Tinted Lenses. The lenses are prescribed at Batty and Dexter Opticians using the ReadEZ Screening System.
Recent imaging studies suggest that the symptoms of visual stress may be caused by a hyper-excitability of the visual cortex in the brain. The problem may be linked to photophobia and migraine.
Dyslexic individuals and those with Meares-Irlen Syndrome are likely to experience visual stress, although visual stress is quite distinct from dyslexia and the phonological difficulties with which dyslexia is usually associated.
Many thousands of individuals who find reading tiring and unpleasant, unknowingly experience visual stress.
They have to work harder than their peers to achieve the same outcomes, often with extra tuition. Many could be helped by overlays or Precision Tinted Lenses. It is therefore essential that every child who struggles to read is referred to a vision practitioner who can undertake a full eye examination and check for the presence of visual stress.
A diagnostic process has been designed that allows for the identification of visual stress, thereby distinguishing it from other barriers to reading. This is achieved by the simple selection of an optimum coloured overlay placed over the reading matter.
The Signs and Symptoms of Visual Stress
All or some of the following may be present:
- Movement of the printed text
- Patterns in the print (described as rivers or worms)
- Tiring easily whilst reading
- Headaches or visual discomfort
- Using finger as a marker on the page
- Frustration and low self-esteem
Colour can make a significant difference to the quality of life for migraine sufferers.
Migraine is often associated with a sensitivity to glare, and most patients are photophobic during an attack. The glare sensitivity occurs in response to bright lights and bold geometric patterns, particularly those of stripes. The sensitivity is associated with an abnormally strong response in the visual cortex of the brain.
Both the brain abnormality and the sensitivity are reduced by Precision Tinted Lenses. Other coloured lenses are without beneficial effect. Occasionally the Precision Tinted Lenses prevent migraine attacks. More usually they enable patients to continue their daily activities despite attacks and to cope in environments that would normally make them seek out dark rooms.
Research: In 2011 Professor Jie Huang, Michigan State University and his team, that included Professor Arnold Wilkins, published the first study, using brain imaging that showed a considerable reduction in visual cortical hyper activation in the brain when prescribed Precision Tinted Lenses.
The study concludes that normalisation of cortical activation in migraines with Precision Tinted Lenses, suggests a neurological basis for the therapeutic effect of the lenses in reducing cortical hyper activation.
Other neurological conditions have been shown to benefit from the use of Precision Tinted Lenses. Research has shown that reading can, in some cases, improve significantly in Autistic spectrum individuals with the use of a precision colour. Acquired brain injury sufferers have also, anecdotally, shown benefits with a chosen colour. This work is ongoing.
The ReadEZ Screening System
The ReadEZ Screening System is designed for Optometrists involved with the diagnosis and management of Meares-Irlen syndrome.
The Screening System enables the Optometrist to diagnose and manage Meares-Irlens syndrome and includes a powerful software app which runs on the consulting room PC, a set of 13 trial clip-ons, 12 ReadEZ Overlays and 12 ReadEZ Reading Guides.
How it works
The ReadEZ Screening Software simulates the effects of coloured overlays and spectacles by changing the background colour of the screen.
To determine the optimum colour, a sample of text is displayed on the screen while the colour of the background is changed systematically. The observer is asked to report which colour is most comfortable or minimises their symptoms. The effectiveness of the colours is assessed using a test devised by Professor Wilkins known as the Rate of Reading.
Computer screening is fast, thorough and sensitive and compares very favourably with manual screening.
Step by Step Guide to the Screening Procedure
The patient views a passage of text on the screen against a white background and is asked to rate the severity of any symptoms they may experience.
Baseline rate of reading:
The patient is required to read a paragraph or random words against a white background. The number of words read in one minute and the number of errors made is recorded. This forms a baseline for the fluency of reading.
Two colours are presented successively and the patient is required to select the “more comfortable” colour. The computer uses a sophisticated algorithm to compare different combinations of colours in order to determine the best colour overall. This algorithm generates a number of indices describing the consistency of the patient’s responses.
Rate of reading with preferred colour:
Having determined the preferred colour, the program repeats the rate of reading test with this colour in order to establish if the ReadEZ tint improves the fluency of reading. An improvement of 10% is generally considered to be the threshold for prescribing a coloured overlay.
The software includes a powerful integrated database for storing results and generating reports. Full details of every screening are stored automatically avoiding the need to take any notes during the test
The program presents a visual comparison of the symptoms and rate of reading result with and without a coloured overlayor tinted lens.
ReadEZ Clip-on trial set
Book your Meares-Irlen Syndrome screening test at our Southport Opticians - Call 01704 540009