Colourimetry

How colour can alleviate visual discomfort

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 using specialist equipment called a Colorimeter.

Dyslexic individuals are more likely to experience visual stress than others, although visual stress is quite distinct from dyslexia and the phonological difficulties with which dyslexia is usually associated.

Click here for a short video, showing what reading is like for someone with visual stress (dyslexia)

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 a finger as a marker on the page
• Frustration and low self-esteem 
• Migraine

Coloured Overlays

An essential aid for vision professionals as the first step in identifying Visual Stress.

Coloured Overlays are used widely both in the classroom and by vision professionals in practice. Moderate to significant improvements in both reading rate and accuracy are not uncommon when the optimum overlay is prescribed.

Overlays are coloured sheets of robust transparent plastic that are placed over a page of text when reading. The assessment pack consists of 12 overlays of different colours. The colours have shades that differ systematically. The variety of shades is sufficient to provide a shade optimal for each individual. Assessment involves the presentation of each overlay in turn for comparison with others placed beside it. The assessment can be carried out by our specialised vision professional.

The Overlay Testing Set includes the Wilkins Rate of Reading Test, which measures reading speed independently of language comprehension. It quantifies the improvement in reading.

Our Intuitive Colorimeter Machine

To provide the best care for our patients, we have invested in specialist machinery to help our patients find a solution to their visual stress. Our machine is acknowledged worldwide and offers many thousands of colour combinations so that we can find our patient’s optimal colour setting.

Precision Tinted Lenses 

After a trial period, if your temporary tinted lenses work well for you, your Precision Tinted Lens can be prescribed and precisely produced from specially dedicated laboratories where they are dyed to an exceptionally high degree of accuracy.

They are then scanned using a calibrated spectrophotometer linked to a Medical Research Council software programme ensuring accuracy of the prescribed colour that works for you. Any requirement for refractive prescription can be also be incorporated into your tinted lenses. Each pair of prescribed Precision Tinted Lenses has an accompanying Certificate of Authenticity.