We use visual field tests to assess your field of vision and in particular your peripheral vision (round the edges rather than central vision).
Please note
During this test we use eye-drops to dilate (open) the pupil – the drops can cause blurring of vision for a few hours, and it can take up to 24 hours for the effects of the drops to wear off. Therefore we advise that you do not drive yourself home from the eye clinic.
Before your test
You will be given a hand held buzzer, which you will be told to press when you see a light. One eye will be covered and you will be positioned on the machine with your chin on the chin rest and head against the bar. The test takes about six minutes for each eye.
During your test
You will need to keep your eye fixed on the light on the centre of the white bowl. The computer will then display flashes of light in different areas and you have to press the buzzer every time a light flashes. Do not worry if you wrongly pressed or missed pressing the buzzer by mistake. The computer will retest that area again.
You must look at the central light at all times and avoid following the flashes in the periphery by moving the eye.
Please blink normally as you do not miss the flashes if you blink normally.
The flashes may be of different sizes and brightness and there may be periods when you may not see the flashes at all. The computer is trying to determine the smallest and the dullest light you can see.
The test is not painful and enables us to determine very early loss of vision in the periphery and also the progression of glaucoma.
After your test
If the assessment show you do have glaucoma, the nurse may prescribe some eye drops for you to put in every day. In the majority of cases this is sufficient to control the pressure within the eye and so prevent your sight from getting worse.
If you have any problems at all with your drops you should tell your specialist who may suggest alternative treatment. It is most important that the drops are used regularly and also that you use them as usual on the days when you are due for your check-up at the hospital.
You will need to attend the Eye Clinic for regular checks of the eye pressure. If the pressure remains high despite using drops your specialist may advise you to have a small operation.
Glaucoma tends to run in families and so you should encourage the older members of your family to have their eyes checked every year.
If you are are driver and have been diagnosed with Glaucoma you should notify the Driver and Vehicle Licensing Authority (DVLA) – the address will be on your driving licence. You should also inform your Insurance Company.
