Visual Field Testing

Your field of vision is what you can see directly in front of you as well as above, below, and to the sides (the periphery) without moving your eyes.

Your best vision will normally be in the centre, with things gradually getting less clear the further out into the periphery they are. Some eye conditions, such as glaucoma, ocular hypertension and retinitis pigmentosa can affect your visual field. Certain neurological disorders, diabetes, and stroke, can also affect your visual field. The purpose of a Visual Field test is to:

• To find any reduction in sensitivity within your field of vision
• To assist the doctor in diagnosing and treating medical conditions that may affect or have affected your vision
• To monitor any changes in your field of vision 

It is quite common for chronic eye conditions such as glaucoma and ocular hypertension to have tests repeated at regular intervals to monitor any changes. Changes can be very gradual and a person may not detect them at all by themselves. The visual field test can pick up very small, subtle changes in the visual field so that treatment may begin before any significant visual loss occurs.

1. Visual acuity check:  Your visual acuity (the sharpness of your vision) will be checked before the visual field test, so if you have glasses for distance (driving, television, bifocals, etc.,) please bring them with you.
    
2. Visual Field test:  Normally, each eye is tested separately. A special patch will be placed on the eye not being tested, but for best results both eyes should still remain open during the test. You will be given a buzzer to press and positioned at the visual field machine by the orthoptic assistant. You will be given instructions on how to do the test. On average, each eye will take approximately 3 – 7 minutes to complete the test, although some tests can take longer.
    
3. Test instructions:  During the test, you should watch the orange light inside the machine. It is very important to try to keep your head and eye(s) as still as possible, but do blink normally so that your eye does not get dry.
   
   Fainter lights will begin to appear, one at a time, off to the sides. You will press the button whenever you see one of these lights.
   
   It is normal to have times where there are no lights to be seen. Sometimes the lights will be so faint that it may feel as if you are missing them. This is also normal . The test is measuring how faint a light you can detect, not how many. For a good result, it is more important to be accurate than fast.
   
   We will let you know when the test starts and stops. If you are uncomfortable at any time sitting at the machine, please tell us so we can adjust your position or even pause the test for you to rest. 
    
   After the test is complete, the results will be passed to your doctor.

You will not get eye drops during the visual field test. If you are seeing the eye doctor or having photographs/scans of the eye on the same day you may have dilating eye drops after this test.

Please allow 45 minutes for your visual field appointment. Some tests take more time than others.

Unfortunately it is not always possible to have both appointments on the same day. Please keep your separate visual field appointment. It is important that the visual field results are available for the doctor to make a decision on your treatment when you see them.

If you need to change or cancel your visual field appointment time, please call the ophthalmology outpatient appointment office on 01382 740210 Monday – Friday between 8.30am -1pm.