Visual stress is a term used to describe visual discomfort and perceptual distortions in printed text, and is suffered by some people who struggle to read. Symptoms can be experienced in varying degrees from simple fatigue to difficulties when looking at text.
Symptoms may include:
- Movement of printed text
- Blurring of print
- Letters changing in size or shape
- Patterns in the print (sometimes described as rivers or worms)
- Halos of colour surrounding letters or words
- Tiring easily whilst reading
- Headaches or visual discomfort
Some individuals who find reading tiring and unpleasant may unknowingly experience Visual Stress.
How might colour help?
In some cases, the symptoms of visual stress can be reduced by the use of coloured filters: a coloured overlay placed over text or coloured lenses worn in spectacles. It is thought that offering a large number of colours allows for optimal results. The Intuitive Colorimeter™ offers many thousands of colour combinations.
As a first step, it is important that anyone who struggles to read should be referred to a vision specialist. A primary eye examination which checks for the existence of refractive errors, such as long or short sight or astigmatisms, is free of charge to school age children under NHS provision. It is important to rule out or treat other vision deficits before testing for visual stress.
Once an eye examination has been carried out, the practitioner may then assess for visual stress. At this point the practitioner may use an overlay as part of the testing procedure.
Whilst coloured overlays are useful when reading from a book, precision tinted lenses are more convenient when copying from the board or from another book or for those individuals who are particularly light sensitive and may develop headaches and eye strain when attempting to read.
If visual stress is found to be present, the practitioner may suggest prescribing precision tinted lenses as a longer term aid. From simple improvements in reading performance to dramatic transformations in quality of life, precision tinted lenses may offer a range of potential benefits.