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Ophthalmology

Visual Stress and Coloured Overlays

Patient Information Leaflet

Introduction

The aim of the visual processing difficulties (VPD) clinic is to diagnose and treat visual problems which will interfere with a child’s education. The clinic is not intended to replace the expertise of the teachers, the special educational needs coordinators (SENCOs), the inclusion teams or the educational psychologists, and neither can our assessment give any diagnoses of dyslexia or any other educational problems.

Our expertise lies in the area of visual processing difficulties, such as ocular motility problems, visual stress, and deficiencies in eye tracking movements and visual perception difficulties. The child may well have some characteristics of dyslexia and an underlying visual problem (for example, over 50 per cent of dyslexics will have visual stress). However, treating one area of visual difficulty will not be a miracle cure for the dyslexia or a specific learning difficulty, but it will help the child manage their problem in a better way.

  1. Q) What is visual stress?
  2. A) Visual stress (sometimes called ‘Meares-Irlen Syndrome’ or ‘Scotopic Sensitivity Syndrome’) is the experience of unpleasant visual symptoms when reading, especially for prolonged periods. Symptoms include illusions of shape, movement and colour in the text, distortions of the print, loss of print clarity, and general visual irritation. Visual stress can also cause sore eyes, headaches, frequent loss of place when reading and impaired comprehension.
  3. Q) What causes visual stress?
  4. A) Visual stress is thought to be stimulated by the stripy effect of the writing, which overstimulates the visual cortex in the brain and produces symptoms.
  5. Q) How does a coloured overlay help?
    A) Coloured overlays are transparent sheets of coloured plastic that can be placed over a page or a book. They are used to colour the text without affecting its clarity. The colour reduces the perceptual distortions of text that children sometimes describe. They enable some children to read more fluently, with less discomfort and fewer symptoms of visual stress.

Coloured overlays and coloured glasses can increase the speed of reading, although with conventional text, the improvement may only be apparent after 10 minutes of reading, when the child would begin to tire were an overlay not used. If the text is closely spaced, the benefit is more immediate.

The children who benefit may already appear to be good readers, but usually they have difficulty with reading. They usually suffer visual discomfort when reading and when questioned, and will often report visual distortions of the text.

A specialist orthoptist has assessed the child’s eyes and prescribed the coloured overlay as a trial. The overlay may not be the correct colour or the child may not like to use it. If the overlay is simply making the page look different, the effect will wear off. If the child voluntarily uses the overlay for one school term, then this is a positive indicator that colour will be beneficial.

The child does not have to use the overlay if they feel it makes no difference. The response to colour is subjective and the user is the best person to judge if there is any benefit.

  1. Q) How is a coloured overlay used?
    A) The coloured overlay should be laid over the text the child is reading. The overlay should be flat and touching the page, and positioned so as to avoid reflections from the surface.

The overlay should not be creased, and it is a good idea to keep the overlay in an envelope when not in use. The child can touch the overlay to help when reading and it can be wiped clean.

What if I have any problems or questions after reading this leaflet?

Please contact the Orthoptic Department at Russells Hall Hospital on 01384 456111 ext. 3636 (9am to 4.30pm, Monday to Friday).

Eye emergency, out of hours

In case of an eye emergency after the closing hours of the Eye Clinic (including weekends and bank holidays), please contact the eye doctor on call by ringing the switchboard at:

Birmingham and Midland Eye Centre on 0121 507 4440

The doctor on call is usually based at the Eye Centre, City Hospital, Dudley Road, Birmingham. They may need to call you back, and if necessary, they will arrange for you to visit them.

Note: The information in this booklet is provided for information only. The information found is not a substitute for professional medical advice or care by a qualified doctor or other healthcare professional. Always check with your orthoptist if you have any concerns about your condition or treatment. This is only indicative and general information for the procedure. Individual experiences may vary and all the points may not apply to all patients at all times. Please discuss your individual circumstances with your orthoptist.

We are always happy to answer any questions regarding your child’s treatment. If, after reading this leaflet, you still have concerns or questions, please call the department on 01384 456111 ext. 3636.

Author
Pam Grewal
Specialist orthoptist

For further information visit: www.orthoptics.org.uk/patients-and-public

If you have any questions, or if there is anything you do not understand, please contact the Russells Hall Hospital switchboard number on 01384 456111 and ask for the relevant department who issued this leaflet.

If you have any feedback on this patient information leaflet please email dgft.patient.information@nhs.net

This leaflet can be made available in large print, audio version and in other languages, please call 0800 073 0510.

Visual Stress LM/PG/CS/ST/DP/09 2024/v4 – review 06 2027 DGH/PIL/02076