Contrast Sensitivity Test

What it measures

Your contrast sensitivity — the faintest difference in shading you can still detect. Unlike acuity, which uses high-contrast black letters, this measures how well you see pale, low-contrast detail, which is important for night driving, reading in dim light and recognising faces.

How it works

A letter is shown against the page in grey, starting clearly visible and fading toward the background across several steps. At each step you identify the character or say you can't see it. The faintest contrast level you still read correctly maps to a contrast-sensitivity band of normal or reduced.

Tips for an accurate result

• 1Don't lean in — Moving closer changes the task — keep a steady, comfortable distance throughout all the steps.
• 2Reduced contrast can precede other changes — Contrast loss can appear early in conditions like cataract or glaucoma, even when acuity still reads 20/20.
• 3Lighting and screen matter — Results vary a lot with display quality and ambient light, so track yourself under similar conditions.
• 4Trouble in dim light? Get checked — If faint detail or night vision is harder than it used to be, mention it at your next eye exam.