• Reference Number: HEY-746/2019
• Departments: Neurophysiology
• Last Updated: 31 May 2020

Introduction

This leaflet has been produced to give you general information about your procedure.  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and the healthcare team, but may act as a starting point for discussion.  If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team caring for you.

What is a pattern reverse visual evoked potential?

A Pattern Reverse Visual Evoked Potential is a test of the pathway between your eye and your brain (the optic nerve). The test provides a way of assessing how well the nerve is working.

Why do I need a PRVEP?

Your doctor has requested we perform a PRVEP because you have reported some symptoms that raise the possibility of a problem affecting your nerves.  There are many conditions that can cause these problems. Your symptoms may not necessarily affect your eyes or your vision.

Can there be any complications or risks?

• Very occasionally people may experience a slight local reaction at the electrode site. This may cause reddening and soreness.  These symptoms resolve quickly on removal of the electrodes. If you experience these symptoms, please inform the staff attending to you.

• If you have to have threads (see below) in your eyes you may feel very mild discomfort and have some slight reddening of the eyes afterwards. Your vision will NOT be affected.

How do I prepare for the PRVEP?

Please read this information leaflet.  Share the information it contains with your partner and family (if you wish) so that they can be of help and support.  There may be information they need to know, especially if they are taking care of you during / following this examination.

• Please ensure your hair is freshly clean and dry with no spray or gel etc. on it.
• If you wear glasses please bring them with you; contact lenses cannot be worn for some of the testing so glasses are needed if you have them.
• Please do not bring children with you as we are unable to accommodate them unless you bring someone to supervise them in our waiting area.
• Please inform us of any eye conditions you may have on the day of the testing.
• Take your medication as normal unless otherwise directed by your doctor.
• Please bring a list of any current medication you are taking.

What will happen?

• On your arrival in the department we will obtain your consent for the procedure before your investigation begins.
• The clinical physiologist performing the PRVEP will introduce themselves, explain the test to you and will be happy to answer any questions you may have.
• The clinical physiologist will first check your visual acuity.
• You will be asked to sit on a chair and the clinical physiologist will measure your head and mark some points on it with a soft pencil. Then a few small electrodes will be placed on your head using sticky paste.  Prior to this the physiologist will rub your head with some gritty paste to obtain a good contact with your skin.
• You will then be asked to look at the centre of a screen that has moving black and white squares on it. Each eye will be tested separately.
• This test is totally painless and there are no after effects. The test can take up to 45 minutes.
• Sometimes following the test, it may be necessary to undertake further testing which involves placing a fine thread across the surface of your eye and asking you to watch the same screen with both of your eyes together. This will be explained to you on the day in more detail and drops can be placed into your eyes if needed so you will not feel the fine threads.  This extra testing will take about 30 minutes.

What happens afterwards?

• The electrodes will be removed and your head cleaned with warm water. You may wish to bring a brush or comb with you to tidy your hair.  Any residue of paste can be removed by shampooing the hair.
• Once you have left the department the recording will be reviewed by the clinical physiologist and then by a member of the medical team who will send a report to the doctor who referred you for the PRVEP. This usually takes up to two weeks.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Neurophysiology Department (01482) 675339 / 675388.

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

• you must be able to give your consent
• you must be given enough information to enable you to make a decision
• you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.