What do you see when you look at a page of text?

Some adults and children see more than letters or words. They see things that are not really there: illusions such as movement of the words, movement of the letters, blurring, colours or shapes and describe the distortions in a variety of ways: They may say the letters “fizz”, “wobble”, “shimmer”, “fly of the page”, “drop off the end of the line”, “the page comes up and hits my eyes the white paper may glare and cause eye strain or headaches. The result in perceptual distortion and visual discomfort may interfere with reading. The distortion is common in adults and children who have binocular vision problems. It can also occur quite independently of any ocular problem in people whose eye sight is otherwise perfect. Frustration and low self-esteem can occur in adults and children who are under-achieving due to visual stress.

There is a solution for distortion when reading:

Scientific research has shown that visual stress from reading can be reduced by colouring the page using spectral filters. The filters are either placed
directly over the page (these are known as coloured overlays) or they
are worn in spectacles (Precision Tints).

The Intuitive Colorimeter is an instrument designed and developed by the Medical Research Council Applied Psychology Unit, for selecting the optimum colour for the relief of Visual Stress in Dyslexia, Migraine and Photosensitive Epilepsy.