colorimeterIntuitive Overlays, Intuitive Colorimeter and Precision Tints to help people with reading problems and dyslexia.

Some individuals experience visual discomfort and distortion on attempting to read. These distortions include blurring of print, movement of words and letters while reading, fading of print while reading, appearance of patterns in the text and glare effects. They often report with symptoms of headaches and in some cases with light sensitivity.

The use of colour, either in the form of overlays or as tinted lenses, to help these symptoms is not new. Until recently, there was no controlled and masked investigation available to prove their benefit and to rule out a placebo effect.


In the early 1990s, a double –masked placebo controlled study into the use of coloured lenses for dyslexia was conducted by the Applied Psychology Unit of the Medical Research Council. Professor Arnold Wilkins led this study with a team of optometrists and special need teachers. This study proved that the application of overlay filters may be of benefit. They developed a rigid clinical procedure to exclude the possibility of placebo.




Intuitive Overlays
Intuitive overlays are transparent sheets tinted in a range of different colours.
The different overlays are being presented to the patient in succession, and by a process of elimination, the overlay giving the maximum relief can be determined.

The appropriate colour for reducing distortion varies from person to person.
In order to rule out a placebo effect, the Wilkins Rate of Reading Test is then applied. This test makes it possible to determine whether the patient has an increased rate of reading (increased speed) in the presence of the overlay. The chosen overlay filter is then issued to the patient to be used for reading.

If it is still being used persistently six weeks later, spectacles with specifically prescribed coloured lenses may be considered. These are more convenient to use, and they can reduce eyestrain from stimuli other than text, such as whiteboards and computer screens.

They have also been found to help migraine sufferers if they have a visual trigger.

The Intuitive Colorimeter
The Intuitive Colorimeter allows the prescribing of tinted lenses for each individual (i.e. coloured spectacle lenses) to be a controlled procedure that can be completed in a period of twenty or thirty minutes.
At the end of this stage of examination, it should be possible to determine which colour and to what intensity it results in relief of symptoms.

The standard of tinting of the lenses is carried out to a high degree of accuracy and uses specially developed dyes.
This system has now been in clinical use for approximately ten years and for research purposes for a considerably longer.
Cerium website for more information is

Many patients report back that there is a significant reduction in headaches with the use of the lenses and that the users are starting to read for pleasure for the first time, as well as having an increased rate of reading and increased concentration span.

It is important to remember that only a proportion of people with dyslexia have visual problems associated with specific learning difficulties and that only a percentage of these have Meares-Irlen Syndrome or sometimes called Scotopic Sensitivity (presence of visual discomfort and distortion that cannot be explained by refractive and binocular anomalies or the presence of pathological conditions and that responds to the presence of colour). The symptoms of Meares-Irlen Syndrome closely resemble those of binocular visual anomalies and can also resemble those produced by pathological conditions. A detailed eye examination will reveal any binocular anomalies and possible pathology, which have to be treated before colour is considered.

At our practice, we will carry out a detailed eye examination at the first visit, and we will treat any problems with binocular vision first, with either exercises or spectacles.

During the second appointment, we will carry out the overlay assessment and issue a coloured overlay and the need for one can sometimes be confirmed with the Rate of Reading Test.

About six months later, we will consider a colorimeter assessment if the coloured overlay has proven to be of benefit in the meantime.

Please ask our staff to e mail or post you some more information and prices.

If you have far to travel to us and would like both appointments at the initial visit please ask our reception staff to arrange a double appointment.

Please click here to read more on Dyslexia.

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