What are electrodiagnostic tests?
Electrodiagnostic tests involve recording tiny electrical responses that are produced by the eyes and the brain when a child looks at flashing lights or moving patterns. These electrical responses can be abnormal in many conditions that affect the eyes, the nerve pathways that connect the eyes to the brain and parts of the brain concerned with vision.
What are the benefits of having this test?
Electrodiagnostic tests can be useful in determining whether a child has a particular condition, the location of the problem and its extent. They can also be used to estimate the level of vision.
Where will the test take place?
Testing takes place in the Eye Department in Outpatients at the Royal Hallamshire Hospital. Please report to the Orthoptic Clinic Reception and hand over your appointment letter. This is located opposite the multi-storey car park on ‘A’ floor through the children’s entrance labelled 1 A. There is a ramp access if required.
Car parking at the hospital and in the surrounding areas is very limited. It is recommended that you leave plenty of time to allow for parking before the appointment time or use public transport wherever possible.
What happens during the test?
Your child will be asked to sit on a comfortable chair, (babies and toddlers sit on your lap). Your child will then have small buttons (called electrodes) attached to the skin on the head and the face with some paste. These buttons pick up and record electrical responses produced by the eyes and the brain. Your child will be shown coloured flashing lights and moving patterns on a television screen.
Are there any risks or side effects?
The skin needs to be prepared by gently rubbing it with a gritty paste before fitting the electrodes. Sometimes this can cause mild irritation. Flashing lights can be a problem for people with photosensitive epilepsy. However, we avoid unsafe flash rates and regularly test epileptic patients without any difficulty. The flashing lights cannot harm your child's eyes.
Sometimes your child may require eye drops to enlarge the pupils. The drops can make vision blurred for several hours; therefore you may prefer your child to remain away from school or other activities until the effect of the drops has worn off. It would be a good idea to bring a pair of sunglasses and / or peaked cap because bright lights may be uncomfortable until the pupils are able to return to their normal size.
Are there any alternatives to this test?
Much of the information we get from these tests cannot be obtained in any other way. Some parts of these tests can be done in theatre under general anaesthetic.
How long will the test take?
Testing usually takes less than one hour. Some tests can take longer because your child may need their eyes to adapt to the dark or your child maybe having eye drops to enlarge their pupils.
What should we bring with us?
As well as your appointment letter, you should bring any prescription glasses with you because they may be needed for the test, even if your child finds them of little or no use. Successful testing often depends on having plenty of favourite toys, food and drink.
Can we bring someone else with us?
Yes, but we ask that you are not accompanied by more than one other person in the test room because space is limited. Some tests are done under darkened conditions; please consider that other children might become bored and could distract the one being tested! If you do need to bring other children, we have a playroom they can use if accompanied by another adult.
How can I amend my appointment?
If you wish to make a change to you appointment please telephone the Electrodiagnostics Clerical Officer on 0114 27 12978 as soon as possible.
When will we get the results?
The results will be given to you at your child's next clinic appointment by the Consultant Ophthalmologist who requested the tests. We are unable to give you results on the day.
What do I do if I have any questions or concerns?
If you have any concerns about the test, please contact:
Dr. Lawrence Brown (Lead Clinical Scientist) on 0114 27 11746
