Colorimetry and Coloured Overlays

Visual stress is a condition experienced by many adults and children, which can lead to eyestrain, headaches and difficulty whilst reading. Visual stress to pattern sensitivity in disorders such as dyslexia, migraine, light sensitivity and epilepsy and can be responsible for distortions on the printed page. Distortions include amongst others blurring of print, movement of words and letters, fading print and appearance of patterns in the text.

What are these Coloured Overlays ?

Coloured overlays are clear coloured plastic sheets that can be placed over a page in a book. They work by reducing the perceptual distortions of text (some clients say the words go fuzzy or jump about.) These signs are characteristic of a condition that some have called Meares-Irlen Syndrome or Scotopic Sensitivity Syndrome.

There is evidence to suggest that some people with dyslexia and/or specific learning difficulties, find it easier to read more fluently and quickly when using overlays. They are available in different colours and patients should try them to see which ones they feel most comfortable with. If after a period of time, the patient receives a continued benefit, spectacles can be made, in order that they may use them in other areas of their work.

It is necessary to have a full eye examination prior to being assessed as this can often reveal other previously undiagnosed visual problems. If you suspect someone may have a problem in the first instance coloured overlays are a logical and inexpensive first step towards treatment. This process can be carried out in our Saffron Walden practice by a fully qualified dispensing optician.

The colorimetry test takes about an hour and with the aid of the Colorimeter uses many different colour combinations and depths of colour to create a specific tint for the patient. People who experience movement of text, patches or colours within texts or anyone finding reading "stressful", as well as people with dyslexia, migraine or photosensitive epilepsy have found great benifit from coloured lenses chosen by colorimetry.

Chromagen Lenses

In our Cambridge office, Sean Rock offers Chromagen assessment, suitable for patients who have certain forms of colour vision deficiency, most effective with red/green problems (technically known as Deutan and Deutanamalous defects). Tests are performed to establish if an individuals appreciation of colours can be improved upon using selective colour filters, often worn as a contact lens in one eye only. Occasionally a different colour filter is required for both eyes and can be corrected by contact lenses or tinted spectacles.