Visual Field Test: Purpose, Test Details & Results

Purpose of Visual Field Test

The visual field test is a cornerstone of eye care, allowing clinicians to map what you can see “out of the corner of your eye” (your peripheral vision) as well as your central vision. This test isn’t just about eyesight—it’s about protecting quality of life, as changes in your visual field can reveal early signs of diseases like glaucoma, neurological conditions, and retinal disorders. Understanding what the test is for can help reduce anxiety and make you an empowered partner in your own eye health.

Table 1: Core Purposes of Visual Field Testing

Diagnosing Eye and Brain Diseases

Visual field testing is vital for diagnosing conditions that cause patterns of vision loss. In glaucoma—a leading cause of irreversible blindness—damage to the optic nerve produces characteristic blind spots that may go unnoticed until late in the disease. Testing is also crucial for uncovering neurological problems (like strokes or brain tumors) and retinal conditions (such as retinitis pigmentosa) that may alter the visual field in unique ways 8 9 12.

Monitoring Progression and Treatment Response

Once a diagnosis is made, regular visual field tests help doctors track whether your vision is stable, improving, or worsening. This is especially important in glaucoma, where small changes over time can influence management decisions. Guidelines recommend at least one test per year in glaucoma, but more frequent testing may be needed after diagnosis or when progression is suspected 7 8 10.

Early Detection and Screening

Some visual field tests serve as screening tools, helping to catch disease early—even before symptoms appear. While traditional confrontation tests are easy to perform in a clinic, they are not very sensitive and may miss subtle or early defects. Automated or home-based tests, now available on devices like tablets and VR glasses, show promise for screening at-risk individuals outside the clinic 1 5 6 12.

Assessing Impact on Daily Function

Visual field loss can affect mobility, driving, reading, and quality of life. Testing isn’t just for doctors—results can help patients and families plan for changes, seek rehabilitation, or make home adaptations to stay safe and independent 8 12.

Visual Field Test Details

Getting a visual field test can seem intimidating, but knowing what to expect—and the range of methods now available—can make the experience much less daunting. Tests range from quick bedside checks to sophisticated computerized exams and even home-based assessments.

Table 2: Visual Field Testing Methods and Modalities

Confrontation Visual Field Test

This is the quickest method—your eye doctor will sit facing you, ask you to cover one eye, and indicate when you see their hand or a small object moving in your peripheral vision. While convenient, confrontation testing is not sensitive enough to catch early or subtle defects. Combining different confrontation techniques can improve detection, but automated methods are recommended for accurate results 1.

Automated Perimetry

Most visual field testing today is done using automated perimetry—think of the Humphrey Field Analyzer or similar machines. You look into a dome and press a button every time you see a flashing light, which can appear anywhere in your field of view. The test maps areas where your sensitivity is reduced or absent.

• 24-2 Test: Maps the central 24 degrees of vision, standard for glaucoma.
• 10-2 Test: Focuses on the very center (central 10 degrees), useful for detecting central vision loss that 24-2 may miss in early disease 9 11 12.

These tests are highly standardized and produce printouts with detailed plots, indices, and reliability scores 8 9 10.

Home-Based and Portable Testing

Thanks to advances in technology, visual field testing is moving beyond the clinic:

• Tablet and VR-based Tests: Use apps on tablets, smartphones, or VR headsets to deliver perimetric tests that correlate well with traditional machines 2 3 4 5 6. These new methods can be performed at home, are less intimidating, and may improve monitoring for patients who can’t travel easily 4 5.
• Self-Testing Features: Some software monitors ambient lighting, tracks eye movements, and includes expert systems to validate the test, making results more reliable and user-friendly 4 5.

Test Patterns and Customization

Depending on your diagnosis, your doctor may choose different test patterns:

• 24-2: Best for general screening and routine glaucoma monitoring.
• 10-2: Critical for detecting early central vision loss, especially in glaucoma suspects or patients with risk factors for central field progression 9 11 12.
• Some newer algorithms and devices allow even more targeted or rapid testing, adapting to your specific needs and the disease stage 8.

What to Expect During the Test

• You’ll sit with your chin on a rest and look at a fixed target.
• One eye is tested at a time; the other is covered.
• Lights flash in different locations and intensities—your job is to press a button whenever you see one.
• The test takes 3–7 minutes per eye, depending on the device and test type 4 6.
• Reliability indices track if you’re attentive, moving your eyes, or pressing too often or not enough 8.

Visual Field Test Results & Follow-Up

Understanding your visual field test results is key to managing your eye health. Results are more than just numbers—they tell a story about your vision, disease status, and what to expect next.

Table 3: Visual Field Test Results and Clinical Actions

Interpreting the Results

Visual field test results are presented as maps with dots or grids, showing which areas of your vision are normal, reduced, or missing. Key indices include:

• Mean Deviation (MD): Overall measure of vision loss. A negative value means loss; the more negative, the worse the vision 4 6 9 10.
• Pattern Standard Deviation (PSD): Measures irregularities or localized defects.
• Reliability Indices: Show if you pressed the button at the right times, kept your eyes still, or responded to “trick” stimuli 8.

Doctors look for specific patterns to distinguish between glaucoma, neurological, or retinal causes 8 9 12.

What if the Test is Normal?

If your test is normal, but you’re at risk for diseases like glaucoma, regular follow-up is still important. Some subtle changes may only appear over time, so annual or semiannual testing is the norm 7.

What if the Test is Abnormal?

An abnormal result may mean:

• Early or established disease (e.g., glaucoma, stroke, retinal disorder)
• Need for further tests (like optical coherence tomography, MRI, or repeat perimetry)
• A change in your treatment plan—adjusting medications, considering surgery, or closer follow-up 8 9 12

Detecting Progression

Serial testing over months or years helps detect changes that indicate progression. The frequency of testing affects how quickly your doctor can spot worsening:

• More frequent tests (2–3 times a year) can catch progression sooner, but gains diminish above twice yearly for most patients 10.
• At least two reliable baseline tests are recommended, with semiannual follow-up being a good compromise for most 10.

Special Considerations: Central vs. Peripheral Loss

• 24-2 vs. 10-2 Testing: Some cases of early glaucoma or glaucoma suspects may have central vision loss that only shows up on the denser 10-2 test, not the standard 24-2. This is especially true in patients at higher risk or with symptoms; adding a 10-2 test can guide earlier, more aggressive treatment 9 11 12.
• In moderate or severe disease, both 24-2 and 10-2 tests correlate well, but 10-2 remains important for tracking the remaining central vision 12.

Home and Portable Monitoring

Emerging home-based and portable tests show high correlation with standard clinic-based machines for moderate to advanced defects. They make it easier to monitor vision over time, reduce clinic visits, and may even improve early detection, though some have limitations in detecting very early disease 4 5 6.

When Results Are Unreliable

Sometimes, results may be flagged as unreliable due to inattention, fatigue, or technical errors. Your doctor may recommend repeating the test or using alternative methods 8.

Conclusion

Visual field testing is a critical tool in modern eye care, underpinning early detection, monitoring, and management of sight-threatening conditions. Understanding its purpose, process, and what the results mean can help you take an active role in your eye health journey.

Key Points:

• Visual field tests are used for diagnosis, monitoring, screening, and functional assessment of eye and neurological diseases 8 9 12.
• Methods range from basic confrontation to advanced automated perimetry and emerging home-based or portable tests 1 2 3 4 5 6 8.
• Test patterns (e.g., 24-2, 10-2) are chosen based on disease risk, stage, and clinical questions 9 11 12.
• Results guide clinical action—normal results mean ongoing monitoring; abnormalities prompt further workup or treatment adjustments 7 8 9 10 12.
• Regular, reliable testing is crucial for early detection and timely intervention, especially in glaucoma 7 10.
• New technologies are making visual field testing more accessible, portable, and patient-friendly 2 3 4 5 6.

By staying informed and engaged, you can help preserve your vision and quality of life for years to come.