This free online astigmatism test uses the classic fan (dial) chart: a wheel of evenly spaced black lines on a white background. With astigmatism, the eye focuses some directions more sharply than others, so a few lines in the wheel look darker, bolder, or sharper while the lines at right angles look fainter or blurred. You check one eye at a time. If all the lines look equally black and equally sharp, that's a reassuring sign; if some clearly stand out, that's the hallmark cue of astigmatism and a reason to see an optometrist. Because your screen isn't calibrated and your viewing distance is unknown, this is a self-check, not a diagnosis — it can't measure how much astigmatism you have, its axis, or your prescription.
Vision · interactive self-check
Astigmatism Test
Compare the lines in a fan chart with each eye separately. This visual self-check cannot diagnose astigmatism or measure a prescription.
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How the astigmatism test works
1. Set up
Sit about an arm's length from the screen at full brightness. Keep your usual glasses or contacts on if you wear them — this checks how your everyday, corrected vision sees the chart. Test one eye at a time, covering the other without pressing on it.
2. Look at the fan chart
Look at the center of the wheel of lines. Astigmatism focuses some orientations better than others, so with it some spokes look darker, thicker, or sharper, and the ones at 90° to them look paler or fuzzy. Without it, every line looks equally black and crisp.
3. Answer per eye
For each eye you tell us whether the lines looked uniform or whether some stood out. We summarize both eyes and, if anything stood out, point you to an eye-care professional — who can actually measure the axis and power that a screen can't.
What does astigmatism look like on the fan chart?
This is the fan (dial) chart. With no significant astigmatism, every line looks equally black and equally sharp all the way around. With astigmatism, the eye focuses some meridians better than others, so the lines running in one direction look dark and crisp while the lines at 90° to them look fainter, grayer, or blurred — the wheel looks uneven, as if a band across it is darker. You judge each eye separately, because astigmatism often differs between the two.
What this test can and cannot tell you
It shows the real symptom. If some line directions look darker or sharper than others, that genuinely is the classic perceptual sign of astigmatism — and only your own eyes can report it.
A standout result is a cue, not a verdict. It flags that astigmatism may be present and worth checking. It can't confirm it, and a clean result can't fully rule out a mild case on a screen.
It can't measure or prescribe. An uncalibrated screen at an unknown viewing distance can't measure how much astigmatism you have, find its axis, or give you a prescription.
Get it confirmed. For a real measurement and correction, see an eye-care professional. Astigmatism and color vision are unrelated — you can also screen your color vision.
Astigmatism test — frequently asked questions
- How does the online astigmatism test work?
- It uses a fan or dial chart — a wheel of black lines radiating from the center on a white background. Astigmatism makes the eye focus some meridians more sharply than others, so with it some lines look darker or sharper than the rest while the perpendicular lines look blurred. You view it one eye at a time; if some directions clearly stand out, that's a sign of astigmatism worth checking with an optometrist.
- Can an online test really detect astigmatism?
- It can reveal the classic symptom — some line directions looking darker or sharper than others — which is a useful screening cue. It cannot diagnose astigmatism, measure how strong it is, or find its axis, because that needs calibrated equipment and a known viewing distance, and your screen and seating provide neither. Treat a 'some lines stood out' result as a prompt to get an eye exam, not as a diagnosis.
- What does astigmatism look like on the fan chart?
- With astigmatism, the lines running in one direction appear sharp and black while the lines at 90° to them look fainter, grayer, or blurred — the wheel looks uneven, as if a band across it is darker. With no significant astigmatism, all the lines look equally black and equally sharp all the way around.
- Should I keep my glasses on for the test?
- If you wear glasses or contacts for everyday vision, keep them on — this tells you whether your current correction still leaves uncorrected astigmatism. If you want to check your uncorrected eyes, you can also try it without them. Either way, note that a screen test can't replace the refraction an optometrist does.
- What should I do if some lines stood out?
- It's a reason to book an eye exam, not a cause for alarm — astigmatism is extremely common and easily corrected with glasses, contacts, or other options. An optometrist or ophthalmologist can measure the exact axis and power and tell you whether correction would help. If your vision recently changed noticeably, see them sooner.
- Is astigmatism the same as being color blind?
- No. Astigmatism is a refractive error — the cornea or lens is shaped more like a rugby ball than a sphere, so light focuses unevenly and vision is blurred at certain angles. Color blindness is a difference in the eye's color-sensing cones. They're unrelated and you can have either, both, or neither. To check your color vision, take our color blind test.