This test is essential for detecting and monitoring conditions that can cause progressive vision loss, particularly glaucoma, which often affects peripheral vision before central vision. At Pure Sight Eye Surgeons, visual field testing is performed using automated perimetry equipment that provides precise, reproducible results.
Why Is Visual Field Testing Done?
Visual field testing is most commonly used for:
- Glaucoma — detecting and monitoring peripheral vision loss caused by optic nerve damage. Visual field testing is one of the key tests for glaucoma management and is repeated regularly to track any changes over time
- Neurological conditions — certain patterns of visual field loss can indicate problems along the visual pathways in the brain, such as stroke, brain tumour, or optic neuritis
- Retinal conditions — some retinal diseases cause specific patterns of vision loss that can be mapped with this test
- Monitoring medications — certain medications, such as hydroxychloroquine (used for autoimmune conditions), can affect the retina over time, and visual field testing is part of the screening protocol
What Happens During the Test?
The test is straightforward and non-invasive:
- You sit in front of a bowl-shaped instrument and rest your chin on a support
- One eye is tested at a time, with the other eye covered
- You look at a fixed central point inside the bowl
- Small lights of varying brightness flash in different locations across the bowl
- You press a button each time you see a flash of light
The entire test takes approximately 5 to 10 minutes per eye. It requires concentration, and it’s normal to feel like you’re missing some of the lights. The machine is designed to test the limits of your visual field, so not seeing every light doesn’t mean something is wrong.
Understanding Your Results
The results are displayed as a map showing areas of normal sensitivity and any areas where your vision is reduced or absent. Your doctor will compare your results to age-matched normal values and, if you’ve had previous tests, track any changes over time.
A single visual field test provides a snapshot, but the real value often comes from comparing results across multiple tests. This is why regular testing is important for conditions like glaucoma, where changes can be gradual.
Frequently Asked Questions
Is visual field testing painful?
No. The test involves looking at lights and pressing a button. There’s no contact with the eye and no drops are needed specifically for this test.
How often do I need visual field testing?
If you have glaucoma, your doctor will typically request visual field testing every 6 to 12 months, or more frequently if the condition is changing. For other conditions, the testing frequency will depend on your specific situation.
Can I drive after visual field testing?
Visual field testing itself doesn’t affect your ability to drive. However, if your pupils are also dilated during the same visit, you should not drive until the dilation wears off.