Free 3-minute screening • Not a diagnosis — see an ophthalmologist
Glaucoma and contrast sensitivity
A free, calibrated contrast sensitivity screening test. Three minutes, no signup, results stay on your device.
Take the testFree • 3 minutes • No signup • Phone, tablet, or laptop.
Why a CSF check, alongside your eye exam.
Glaucoma damages retinal ganglion cells, often the magnocellular (mid-low spatial frequency) population, before visual-field defects appear on standard perimetry.
Contrast sensitivity can show changes earlier than 20/20 vision or visual fields — it is one of several “early signals” the field has investigated.
Our test is a free, calibrated CSF measurement. If you’re high-risk (family history, age 40+, high myopia, Black or Hispanic heritage, prior eye trauma) it’s a useful adjunct to a comprehensive eye exam — never a replacement.
What this test can and can’t tell you.
It can
- Surface unusual contrast loss at mid-low spatial frequencies.
- Give you a baseline to track over months/years.
- Provide a number to bring to an ophthalmologist.
It can’t
- Does not diagnose glaucoma — IOP, OCT, perimetry, and dilated exam are the standard workup.
- A normal CSF does not rule out glaucoma; early disease can have normal CSF.
- A reduced CSF does not mean you have glaucoma — many causes.
The longer read.
We’ve written about this in depth — with citations and a “what the science says vs. what we don’t know” section.
Glaucoma and contrast sensitivity: an underused early signal→Take the test
Free, 3 min. No signup. Results stay on your device.