Visual Field Loss
Visual Field is the wider extent of your vision, the objects that you can see at the periphery of your sight when looking straight ahead.
What is visual field loss?
When you look straight at something you expect to be able to 'see things out of the corner of our eye'. This is because we have a wide extent of vision.
This is called our Visual Field
Normally one eye can see about 180 horizontally and about 140 vertically. With 2 eyes working together the area is a little larger.
Unfortunately some things can reduce this peripheral vision resulting in visual field loss
How is it treated?
Visual field loss can be caused by problems with the eye itself, with parts of the brain we use for seeing, or with the nerves connecting the eye to the brain.
It is possible to measure how good your peripheral vision is with a Visual field test.
At the Yorkshire Eye Hospital we have the most advanced equipment available to measure visual fields with the 'top of the range' Humphrey' Visual Field Analyser'. This advanced computerised machine projects spots of light. If you see the spot you press a button. The machine then works out where you can see & looks to see if there are any weak areas. For most tests, each eye is tested separately.
Testing usually takes about 15 minutes. Our experienced staff explain the test and guide you through it. It is completely painless, and it won't affect your vision afterwards.
You dont need to do anything special to prepare for a test, but, if you are tired or "under the weather" you may find it harder to do. If you have an appointment planned and this is the case it may be worth phoning up to see if it would be better to re schedule it.
Visual field tests may be done for several reasons.
- to monitor an eye problem (eg Glaucoma)
- to help us diagnose a medical condition (eg some strokes)
- to see if someones vision is good enough for certain tasks (eg driving)
We are able to carry out a wide variety of tests, and in particular the DVLA Esterman test to see if your vision is up to the standard required for driving.
Examples of how problems in different places produce different patterns of visual field loss can be seen at
http://www.brown.edu/Research/Memlab/py47/diagrams/visual-field-defects.jpg
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