Colour overlays for Visual Stress

Visual stress can contribute to reading difficulties in many children and adults. Visual stress is when the visual cortex (the visual processing area of the brain) is over stimulated due to sensitivity to visual patterns, for example lines of black text on white paper. 

Symptoms of visual stress include:

•Blurring of print

•Letters and words appearing as if they are moving

•Discomfort when reading

•Glare from a white page

•Patterns in the print

•In some cases, migraines

Signs of visual stress include:

•Skipping words or lines

•Re-reading the same line frequently

•Moving the book around the desk

•Moving closer or further away from the book

•Poor comprehension of reading content

Visual stress can be a major part of the problem in poor readers even with those who are diagnosed 'dyslexic'. Frustration and low self-esteem can occur in those who experience visual stress therefore early diagnosis is essential.  

How Overlay Assessments and Colourimetry Can Help

Visual stress can be reduced using coloured filters; a coloured overlay placed over text or coloured lenses worn in spectacles. The reduction occurs only when the colour is selected to suit the individual. Individuals find that viewing text through a coloured sheet of acetate or coloured spectacles lenses can eliminate symptoms and improving their reading performance

The Overlay Assessment Process

An up-to-date eye examination is needed before the colour overlay assessment can be done.  Binocular vision testing should be done as a part of the eye examination.

During the colour overlay assessment, the optometrist will use coloured overlays. These overlays are coloured sheets of robust transparent plastic that are placed over a page of text when reading and using the computer. The overlay assessment is used as a screening tool to identify the benefits of working with colour overlays. 

The rate of reading test is designed to measure the effects on reading of visual perceptual distortions of text, such as apparent movement of the words and letters, blurring and coloured halos. Patients are required to read a text that looks like a passage of prose but consists of random words. In the rate of reading test, reading ability is assessed in terms of rate and errors rather than in terms of difficulty of the words read. It is used to compare the individual’s performance with and without the overlay.
 

After the overlay assessment, a report with all of the findings will be emailed to the patient and can be used to give to a teacher, Special Education Needs teacher or other educational or workplace department.