Visual Difficulties
Visual reading difficulties can have an optical or perceptual origin. An optometrist must investigate optical problems before a dyslexia assessment. Information is on: https://www.bdadyslexia.org.uk/dyslexia/neurodiversity-and-co-occurring-differences/visual-difficulties
Meares-Irlen Syndrome (MIS)
A coloured plastic overlays sometimes helps symptoms of visual stress. Visual stress is not always caused by defective eyesight; then it is known as Meares-Irlen Syndrome (MIS). MIS is caused by pattern glare from striped patterns. Pattern glare, considered to have a perceptual origin, is diagnostic of MIS when an optometrist using binocular vision and other tests eliminates optical defects. Certain wavelengths of radiation; glare spots on overhead projectors; repeating patterns such as lines of text or Venetian blinds; lights that flicker with regularity, all can provoke visual discomfort from MIS. An image centrally placed in the field of view adds risk of visual discomfort.
Symptoms
Some symptoms of Meares-Irlen Syndrome from pattern glare are:
- need to rub eyes frequently
- page too bright
- 3D movement
- print moves from side to side or up and down
- words break up or join
- words falls off the page
- print changes size or blurs
- letters muddle or double, appear, fade or darken
- illusions of shape, pattern and motion appear in the dark print or in the white spaces, sometimes described as ‘worms’, ‘rivers’ or ‘waterfalls’
- illusions of colour move across the page
- colour highlights or rainbows around words, letters, people or objects
- eyes tired and sore
- nausea
- dizziness
- discomfort or pain from glare
- headaches
- photophobia
- asthenopia (weakness or fatigue of the eyes, usually accompanied by headache and dimming of vision)
- sensitivity to fluorescent lights or screens