Find answers to common questions about performing a test, preparing your environment, understanding your results and using Visual Field Tracker over time.
What is Visual Field Tracker?
Visual Field Tracker is an online application that lets you explore your visual field, record areas where a test stimulus is perceived or not and save the resulting maps over time.
Its main purpose is not simply to perform an individual test, but to let you build a history of your visual map measurements that can be reviewed and compared.
Is Visual Field Tracker a medical test?
No.
Visual Field Tracker is not a medical test and does not diagnose, monitor, treat or rule out any medical condition.
Your results should not be used to make medical decisions. If you notice changes in your vision or have concerns about your eyesight, discuss them with a qualified eye-care professional.
Can Visual Field Tracker replace a visual field test performed by my ophthalmologist?
No.
Professional visual field examinations use calibrated medical equipment and standardized testing procedures.
Visual Field Tracker is intended as a complementary tool that allows you to explore and record your visual field between professional examinations.
Do I need special equipment?
No dedicated medical equipment is required.
You need a computer with a screen and a physical keyboard. The keyboard is important because the test is designed to be controlled without taking your eyes away from the central fixation point.
Phones and tablets without an attached physical keyboard do not provide all the controls required by the test.
Should I practice before taking my first test?
Yes.
Keeping your eyes fixed on the central point while moving another point around the screen may initially feel unusual.
The Practice Room lets you become familiar with the controls without creating records in your Test History.
Practicing first can make your actual testing sessions more consistent.
Do I test both eyes at the same time?
No. Each eye is tested separately.
When testing one eye, comfortably cover the opposite eye without pressing on it.
Visual Field Tracker can then display the recorded results for the left eye, right eye and their combined visual field.
Why must I keep looking at the centre of the screen?
The test depends on maintaining your gaze on the central fixation point while perceiving the moving stimulus with other areas of your visual field.
If you follow the stimulus with your eyes, you are changing which part of your visual field is being explored.
For this reason, keeping your eyes on the central red point is one of the most important parts of the procedure.
What happens when I can no longer see the yellow point?
Keep looking at the central red point and press the Spacebar.
Visual Field Tracker records the current position.
You can approach an area from different directions to explore where the stimulus becomes visible or disappears.
Do I need to test every position on the screen?
No.
Visual Field Tracker lets you decide how extensively you want to explore your visual field during a session.
You can concentrate on particular areas or perform a more extensive exploration.
How long does a test take?
There is no fixed duration.
The testing method is deliberately interactive, so the time required depends on how extensively you explore your visual field.
You can pause whenever necessary and continue later.
What if I become tired or uncomfortable?
Stop the test and take a break.
Press Esc to pause the current session. You can resume when you feel comfortable again.
Testing for longer is not necessarily better if fatigue makes it difficult to maintain fixation or concentration.
Should I always use the same computer and monitor?
Whenever possible, yes.
If you intend to compare measurements over time, try to keep your testing conditions consistent.
Ideally use the same:
- monitor;
- resolution;
- browser zoom;
- display scaling;
- screen brightness and contrast;
- viewing distance;
- room lighting.
The more similar your testing conditions are, the easier it is to meaningfully compare different sessions.
What is screen calibration?
Screen calibration lets Visual Field Tracker estimate visual angles based on the physical size of your display and your viewing distance.
You calibrate the screen by matching an on-screen rectangle to the width of a standard payment card and entering your approximate eye-to-screen distance.
This allows Visual Field Tracker to display approximate 10°, 20°, 30° and 40° angular references on your saved maps.
Calibration does not change the points you record.
Is screen calibration required?
No.
You can perform a test without calibration. Your recorded map will simply not contain angular guides.
Calibration is useful when you want a spatial reference that makes the map easier to relate to visual field diagrams commonly used in eye care.
Why might two tests look different?
Visual field measurements can vary between sessions.
Concentration, fatigue, fixation, viewing distance, lighting, screen configuration and how extensively you explored an area can all influence the recorded result.
For this reason, Visual Field Tracker is designed around repeated measurements rather than interpreting a single test in isolation.
Can I compare two visual field tests?
Yes.
Visual Field Tracker can compare two saved tests and examine differences in recorded points, overlap between investigated areas, display alignment, test configuration and other characteristics of the sessions.
It also calculates a comparability score to help indicate how similar the testing conditions were.
The comparability score does not measure vision quality or disease progression.
Can I download my results?
Yes.
Saved tests can be reviewed from your Test History and exported as a PDF report.
You can keep the report for your own records or use it when discussing your measurements with an eye-care professional.
Can I add notes to a test?
Yes.
You can add private notes to saved tests.
This can be useful for recording information such as the monitor you used, room lighting, fatigue, interruptions or anything else that may help you understand the circumstances of a particular session later.
What is Vision Simulation?
Vision Simulation uses the visual field recorded during your test to apply a visual effect to an everyday photograph.
It is designed to make visual field loss easier to communicate to friends and family.
Instead of showing someone only a visual field diagram, you can demonstrate how the recorded areas might influence the perception of a familiar scene.
Does Vision Simulation show exactly how someone sees?
No.
Human visual perception is complex. The brain processes and compensates for missing visual information in ways that cannot be reproduced exactly by applying an effect to a photograph.
Vision Simulation is an interpretation based on the recorded visual field, not an exact reproduction of a person's subjective vision.
Are photographs used for Vision Simulation uploaded?
No.
The photograph selected for Vision Simulation is processed in your browser and is not uploaded to Visual Field Tracker.
Can Visual Field Tracker tell me whether my vision is getting worse?
Visual Field Tracker can show differences between measurements and help you explore your recorded visual field over time.
It cannot determine the medical significance or cause of those differences.
A change between two tests does not by itself mean that your vision has deteriorated. If you are concerned about a result or notice a change in your vision, consult a qualified eye-care professional.
Why should I repeat the test?
An individual visual field test represents one measurement performed under one set of conditions.
Repeating the test allows you to build a history and examine whether particular patterns appear consistently across different sessions.
One test gives you a map. Repeated tests give you a history.
Where can I learn how to perform the test?
Visit the How It Works section for a step-by-step explanation of preparation, testing, screen calibration, saving results, comparison and Vision Simulation.
If this is your first time using Visual Field Tracker, we recommend visiting the Practice Room before recording your first test.