Free VCS Test
A free, open-source visual contrast sensitivity test.
The chart above is a Campbell-Robson plot: every column is one spatial frequency, every row is one contrast. The boundary you can just barely see traces out your contrast sensitivity function.
About this test
This measures the faintest pattern you can see at several scales — your contrast sensitivity function. Reduced sensitivity can reflect uncorrected refraction, fatigue, dry eye, cataract, glaucoma, MS, concussion, certain biotoxin exposures, or normal aging. This is a non-specific screening signal, not a diagnostic test. If something feels off about your vision, see a clinician with a calibrated chart.
Best done on the device's largest screen, with normal indoor lighting (not dark), and wearing your usual corrective lenses if any.
Privacy & analytics
Your test results live only in this browser's localStorage.
We do not send results to a server. If you clear your browser data,
your past results are lost.
If you opt in to anonymous usage data we capture event counts that help us improve the test:
app_loaded·test_started·calibration_completestaircase_complete(spatial frequency, threshold contrast, log CS, trials used)test_complete·result_viewed·result_shared·pdf_download
What we never capture: your name, your email, your IP, your individual per-trial responses. Browser-generated anonymous IDs only. We honor Do Not Track — if your browser sets DNT, analytics stays off and you'll never see the consent banner.
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