Astigmatism
Astigmatism happens when the cornea or lens of your eye isn’t perfectly curved, causing light to focus unevenly on the retina. This can make vision blurry or distorted at all distances, unlike nearsightedness or farsightedness, which mainly affect one range. A common way to screen for it is a radial fan chart — a pattern of lines radiating out from a center point. In an eye with normal focus, every line looks equally dark and sharp. In an eye with astigmatism, the lens focuses some orientations more clearly than others, so certain lines can appear bolder, blacker, or more in focus than the rest.
For an accurate at-home screening:
- Sit at a comfortable reading distance, about arm’s length from your screen
- Keep your glasses or contacts on if you normally wear them for reading
- Test one eye at a time, covering the other without pressing on it
- Focus on the center dot, not the lines themselves
Keep in mind that results can be affected by screen glare and display quality, and are intended for awareness only — not a medical diagnosis.
Astigmatism Test
This test uses a radial fan chart to check whether your eyes focus all directions equally, or whether astigmatism might be causing some lines to look sharper than others. It takes about 2 minutes and tests each eye separately.
How This Works
You'll see a chart of lines radiating from a center dot, like the spokes of a wheel. Cover one eye at a time and focus on the dot in the center — don't look directly at the lines themselves.
Look at the Center Dot
Do all the spokes look equally dark and sharp, or do some stand out as bolder or more in focus?
Which Line Looked Boldest?
Click the clock position closest to the darkest, boldest, or sharpest-looking line.