A visual field test is used in diagnosis and to monitor ophthalmic and neurological disease.
The visual field is the area which you can see including your central and peripheral vision.
It is akin to a hillside, with the top of the hill being your central vision and it the lower level it extends, 60 degrees nasally, 50 degrees superiorly, 70 degrees inferiorly and 90 degrees temporally.
Testing your visual field enables and optometrist or ophthalmologist to monitor eye conditions, vision loss and other neurological diseases.
There are two principle methods of testing a person’s visual field:
1. My performing a confrontation test:
The examiner seated in front of the patient brings a target into the visual field and you indicate when you notice it.
2. The other method involves a fixed target.
You sit and look at a large screen, or inside a bowl (perimeter).
Random light flashes appear and you indicate by remote control or vocally how many flashes you see.
In both tests you maintain focus on a target straight ahead and you are indicating when you see objects in your visual field without moving your head or eyes.
An Amsler Grid Test is used to test the central visual field when monitoringconditions such as macular degeneration.
Visual field assessment is important to diagnose and regularly monitor eye problems such as glaucoma, brain conditions and diseases of the retina.
When performing a series of tests every few months,the field test conditions, lighting, eye prescription correction and illuminance of the target objects must be stabilized and maintained.