Visual field testing is a common eye examination often performed during a routine check to analyse patient’s visual field. It helps determine the full horizontal and vertical range of what you are able to see peripherally. Essentially the test measures how much ‘side vision’ you have and it’s used to help diagnose conditions like glaucoma.
At London Vision Clinic, we have the relevant equipment for testing your visual field and can perform these tests in-house.
The purpose of a visual field test is to assess the potential presence of blind spots, which could indicate signs of a variety of eye diseases. Depending on the size and shape of the blind spot (scotoma), it could be linked to optic nerve damage caused by glaucoma.
Brain abnormalities such as those caused by strokes or tumours can also affect the visual field. The visual field test is often used to determine the location of the stroke.
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There are several ways in which this examination can be performed.
This test involves lighted targets being moved from outside of your side vision and in towards the centre of your vision until you see the target. As soon as the target appears, you would indicate this to the doctor – usually by pressing on an indicator button.
This test involves fixed targets, these appear more suddenly into different areas of your vision field (onto a screen). As the target appears, you would indicate this to the doctor, again usually done by pressing a button.
This test is typically used as a preliminary examination, used for screening purposes. In its simplest form, one eye is covered while the other fixates on a target object (eg, doctors open eye) and then you are asked to describe what you see in the far edges of your field of view, or the doctor moves their hand in and out of your visual field to determine the range of side vision.
Other more comprehensive formal types of visual field tests are used for measuring the visual field loss include:
Each eye is tested separately. Sometimes the doctor will want to repeat the visual field test right away to make sure the results are accurate. If the patient is tired, for example, the test results can be unreliable.
Visual field testing is used to measure peripheral vision loss. The tests are repeated at appropriate time intervals to determine if vision loss is progressing or remaining stable. If you are diagnosed with a particular disorder or disease, such as galucoma, visual field tests become a routine part of your treatment.