Ophthalmology• Updated 21 October 2026
Colour Vision Test
A test that checks your ability to tell colours apart, often using Ishihara plates.
Results: Immediately
Quick Summary
Primary Purpose
To screen for colour blindness, for school, jobs or medicines that affect vision.
What It Measures
Ability to see numbers in coloured dot patterns.
Preparation
Bring your glasses.
Overview
Inherited red-green colour blindness is more common in men.
Some medicines, such as ethambutol, can affect colour vision.
What It Measures
Colour discrimination
Red-green and other defects.
How It's Performed
- 01
Plates
Look at a series of dot patterns.
- 02
Answer
Say the number you see.
- 03
Result
Immediate.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Vision Screening(opens in a new tab) · MedlinePlus, US National Library of Medicine