Plain answers about what the test measures, what your result means, and what it cannot tell you.
A three-minute-per-eye visual contrast test that runs on your own phone. It shows circular patches of faint bars at five bar widths and nine levels of faintness, and asks which way the bars lean. The result describes how faint a pattern each eye could still identify at each bar width: your contrast sensitivity.
It was designed by Dr Cameron Jones, PhD, environmental microbiologist, for people who want a simple, repeatable measure of visual function to track over time alongside the quality of the air and buildings they live in.
No. It measures your vision, not your home and not your body's exposure. A low result has many possible causes, most of them ordinary: glasses that need updating, early cataract, tiredness, a dim room or a dirty screen. No test of a person, this one included, can show that mould or any other exposure caused a result.
Whether a building has a mould problem is answered by sampling the building itself, as set out in the Australian Mould Guideline 2026.
Because the people who come to us want to know two things: what is in the air they breathe, and whether anything is changing in how they feel and function. Air and surface sampling answers the first. A short, objective test you can repeat at home is a practical way to keep a personal record of the second, and research has linked contrast sensitivity to a range of environmental and age-related factors. The Evidence page sets out what is and is not established.
The full test shows all 45 patches to each eye and takes about three minutes per eye. The quick test stops a column after two misses in a row and is a little shorter. Use the full test for your first two runs, which set your baseline, and whenever you want the most complete record.
Every report opens with one of three headlines. They tell you what to do next. They do not say whether anything is wrong with you, or why.
The rules behind the headline are listed in every report (version guidance-v1-provisional). They will be reviewed when the normative study reports.
No. It means your result is worth an optometrist's look. Contrast sensitivity falls with many common, often treatable things: an out-of-date prescription, cataract, dry eye, and also conditions worth finding early such as glaucoma, macular disease and diabetic eye disease. Research shows a contrast test on its own is not accurate enough to diagnose any of them, which is exactly why the app sends you to someone who can examine your eyes.
The report lists the reason. The usual ones are that the camera lost sight of your face for much of the test, your distance from the screen changed several times, the app was left part-way through, or your two eyes differed for the first time. A repeat under the same conditions settles most of these.
Not yet, and we will not invent one. A normal range for this test has to come from measuring many healthy people on real phones, at different ages, twice each. That study is planned. Until it reports, the most meaningful comparison is with yourself: two baseline runs, then repeats under the same conditions.
Two runs 2–14 days apart to set your baseline, then about every three months, and before and after any change you want to track, such as remediation of a damp building, moving house, or a change of glasses. Use the same phone, room and time of day if you can.
The three faintest rows are fainter than an ordinary phone screen can be assumed to draw faithfully. They are still shown so the record is complete, but they never contribute to the headline and are shaded in the charts until their real on-screen contrast has been measured.
No. Australian licensing standards assess visual acuity and visual fields, and no licensing cut-off exists for contrast sensitivity anywhere. Reduced contrast sensitivity is, however, linked to difficulty seeing at night and in glare. If you find driving at night or into headlights harder than it used to be, see an optometrist whatever this test shows.
Wear whatever you normally use to read your phone. The test measures your vision as you use it.
Screen brightness at maximum with auto-brightness off, Night Shift, blue-light filters and dark mode off, a normally lit room with no glare on the screen, and the phone held where you would read a message (about 40 cm). The app checks distance with the camera and records the rest from your answers.
The phone edition is designed and checked for phones. It will run on a tablet, but the distance and density checks are tuned for phones, so keep to one device type for your own repeat tests.
To measure how far your eyes are from the screen, from the size of your iris, so the patches are drawn at the right size. The images are processed on your phone and never stored or sent. Only the distance number is kept. If you decline the camera you can type the distance instead, and the report says so.
They are kept on your phone. The app collects no name, email, address or date of birth. You can share the PDF and the full record from the results screen or from Past results at any time. If you later choose to contribute to the research dataset, the record is sent only with your consent, identified by a short code, and can be withdrawn.
Biological Health Services, an environmental microbiology laboratory in Melbourne (ISO 9001:2015, ISO/IEC 17025:2017). Concept and scientific lead: Dr Cameron Jones, PhD, co-author of the Australian Mould Guideline 2026. More at biologicalhealthservices.com.au, mould.net.au and drcameronjones.com.