Visual field plays a vital role in everyday life. 'Visual field' refers to the entire area a person can see while looking straight ahead. This includes peripheral vision, which is critical not just for seeing objects but for interpreting your environment.
A loss of any part of your vision can greatly impact your independence and quality of life. Vision is, of course, crucial in helping us to navigate the world around us, and detect potential hazards. Something that's highly relevant in our place of work, where we need to see things outside our direct line of sight.
Visual field tests, also called perimetry, are important in jobs where safety and health depend on a person's vision. This includes machine operators, commercial drivers, pilots, and transport operators, to name a few.
What is peripheral vision?
Your eyes typically perceive a broad expanse of the space in front of you. Without shifting your gaze, you can observe not only what lies directly ahead but also parts of what is above, below, and to either side.
This area outside of your direct line of sight is known as your peripheral vision. This is within your normal vision, unlike (what we refer to) as blind spots. It encircles the central vision that is directly in front of you. If you have problems seeing things in this area it suggests a loss of peripheral vision.
What is a visual field test?
A visual field test measures your entire range of vision, including central and peripheral. It helps detect vision loss caused by conditions such as glaucoma, stroke, brain tumours, or retinal diseases. An optometrist or ophthalmologist usually performs the test as a preliminary assessment.
Visual field tests have various types. Each one checks a different part of your vision. Here are the main types of visual field test:
Confrontation Visual Field Test
A basic and quick test where the examiner compares their own field of vision to the patient’s. Primarily used as a screening tool to detect gross defects in the peripheral vision.
Automated Perimetry Test
The most commonly used and precise method of visual field testing. Detects detailed vision loss patterns associated with eye diseases like glaucoma and retinal diseases as well as stroke.
Amsler Grid Test
A simple, handheld test used to detect visual field loss. Commonly used to monitor macular degeneration and other central retinal conditions.
Goldmann or Kinetic Perimetry
A manual test using a specialised machine (Goldmann perimeter) to map the visual field. This is useful for patients who may not be able to perform automated tests, including children or those with certain disabilities.
Frequency Doubling Perimetry
A test that uses a special type of visual stimulus involving high-frequency flickering patterns. it is particularly sensitive to early nerve fibre damage so is useful for early detection of glaucoma.
Humphrey Visual Field or Static Perimetry Test
A type of automated perimetry using the Humphrey Field Analyser, a commonly used device in clinical settings. Used for diagnosing and monitoring glaucoma, optic nerve diseases, and other visual field defects.
Microperimetry
A specialised form of perimetry that measures the light sensitivity of specific points on the retina. Useful for evaluating diseases affecting the macula, such as age-related macular degeneration (AMD).
Short Wavelength Automated Perimetry (SWAP)
A subtype of automated perimetry that uses blue light on a yellow background. It helps with early detection of glaucoma, particularly damage to the small ganglion cells that get affected first.
Octopus Visual Field Test
Another type of automated perimetry using the Octopus perimeter machine. Often used for glaucoma diagnosis and management, as well as other visual field defects.
What to expect during the test
The patient is seated comfortably and positioned to focus on a central point. For automated tests, one eye is covered and the patient presses a button each time they see a flash of light or any movement within their peripheral vision.
The results are mapped onto a chart to show any areas of vision loss or abnormalities. Typically, a test lasts no more than five to 10 minutes per eye.
What is a normal visual field result?
A normal visual field result means that someone can see well through the centre and around the edges of their vision. This is measured in degrees from the central point in four quadrants. These quadrants are referred to as temporal, nasal, superior, and inferior. A standard visual field test result shows 90 degrees temporally, 50 degrees superiorly and nasally, and 60 degrees inferiorly.
What does an abnormal visual field result mean?
If someone has a glaucoma-suspicious visual field defect, their optometrist will investigate this thoroughly. If a visual field test provides unusual results, it might suggest initial symptoms of glaucoma. As a result, additional examinations would be conducted for verification.
It's important to note that patients who don't understand a visual field test may struggle to complete it accurately on their first attempt. An optometrist can ask a patient to repeat the test or run further tests to see if a consistent defect exists. Generally, only repeatable field defects are a cause for concern.
What are the limitations of visual field screening?
Visual field screening tests are not comprehensive and may miss small or subtle vision changes. Limitations to consider when conducting a visual field test include:
- Subjectivity of results
- Limited resolution
- Fatigue and discomfort
- Artefact errors
- Environmental and equipment limitations
- Disease-specific limitations
- Accessibility
- To mitigate these limitations, clinicians often interpret visual field tests alongside other clinical findings and imaging.
Vision testers
At Amplivox, we offer several vision testers designed to provide occupational health professionals with a class-leading vision screening programme. This includes traditional desktop devices and PC-based options.
Our vision testers offer a range of test features, including full visual field (peripheral, nasal and central). With fully customisable and automated test routines, our devices can also greatly improve workflow and time management.
For more information on our vision screening devices, please visit our vision testers webpage, contact our customer support team on +44 (0)1865 880 846 or email us.
References
American Academy of Opthalmology, Visual Field Test (Mar 2025). Accessed at: https://www.aao.org/eye-health/tips-prevention/visual-field-testing