---
title: "Colour blindness (colour vision deficiency)"
description: "What colour blindness is, why it is usually inherited, how it affects telling reds and greens apart, and the aids that can help. Clinically reviewed."
url: https://eyehealthguide.org/conditions/colour-blindness/
source: Eye Health Guide
licence: "General information only. Cite the URL and the named medical reviewer."
---

Condition

# Colour blindness (colour vision deficiency)

Medical reviewer [Mr Mohamed Mohyudin](https://eyehealthguide.org/reviewers/mohamed-mohyudin/)· Last recorded site review July 6, 2026

### About this review

This page inherits the site’s previous review record. A separate, current article sign-off has not yet been recorded.

[How review works](https://eyehealthguide.org/reviewers/) · [Official biography & credentials](https://mohamedmohyudin.co.uk/author/mohamed-mohyudin/)

Quick answer

Colour blindness, or colour vision deficiency, is difficulty telling certain colours apart, most often shades of red and green. It is usually inherited and present from birth, mostly affects men, and is not usually serious. There is no cure for the inherited type, but aids and strategies help.

### On this page ⌄

1. Your next step
2. What it is
3. Common symptoms
4. Causes and risk factors
5. Living with it and support
6. Related conditions
7. Frequently asked questions

## What it is

Colour blindness means the colour-sensing cells in the eye do not work in the usual way, so some colours look similar or washed out. Most people with it can see colours, but find it hard to tell certain ones apart, especially reds and greens.

## Common symptoms

Many people adapt and may not realise they see colours differently.

- Difficulty telling reds and greens apart
- Less often, trouble distinguishing blues and yellows
- Confusing colour-coded information such as charts or wiring
- Finding some colours look dull or similar

## Causes and risk factors

Most colour blindness is inherited and present from birth, and it is far more common in men. Less commonly it can be acquired later from eye conditions, some medicines, diabetes, or ageing.

## Living with it and support

There is no cure for inherited colour blindness, but most people adapt well. Good lighting, labelling, and apps that identify colours help with daily tasks, and some people find special tinted lenses useful. An optometrist can confirm the type with simple colour vision tests.

## Related conditions

## Frequently asked questions

### Can colour blindness be cured?

Inherited colour blindness cannot be cured, but most people adapt well, and aids such as labelling, apps, and sometimes special lenses can help with daily tasks.

### Why is colour blindness more common in men?

The most common types are linked to the X chromosome, so men, who have one X chromosome, are much more likely to be affected than women.

### How is colour blindness diagnosed?

An optometrist can diagnose it with simple colour vision tests, such as patterns of coloured dots, often as part of a routine eye examination.

Your next step

## Take this to your appointment

Write down what has changed, when it started, your current medicines and the questions you want answered. Take these to your eye-care appointment.

Sudden loss of sight, severe eye pain or a dark curtain across vision needs immediate assessment. Do not wait to complete a worksheet.

## Sources for this information

These references support the information on this page. Follow the linked source for its full context.

- [National Eye Institute - Color Blindness](https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/color-blindness)