Colour Blindness (Colour Vision Deficiency)
Symptoms, causes, treatment, and when to see an optician
Overview
Colour blindness — more accurately called colour vision deficiency (CVD) — is a condition in which a person has difficulty distinguishing between certain colours. The most common form is red-green colour deficiency, which affects approximately 1 in 12 men and 1 in 200 women in the UK. Total colour blindness (achromatopsia) is extremely rare. Colour vision deficiency is usually inherited and present from birth, though it can occasionally be acquired due to eye disease, medication, or ageing.
Symptoms
- Difficulty distinguishing between red and green shades — they may appear similar or muted
- Confusion between colours such as brown and green, or blue and purple
- Difficulty identifying colours in dim lighting
- Colours appearing less vivid or saturated than others perceive them
- Problems with colour-coded information such as charts, maps, or traffic lights (though the position of lights is typically used as a cue)
- May not be aware of the deficiency — many people learn to compensate and do not realise their perception differs
Causes & Risk Factors
- Inherited genetic mutations affecting the cone photoreceptors in the retina — the most common cause
- X-linked inheritance pattern, which is why the condition is much more common in males
- Acquired colour vision changes due to eye conditions such as glaucoma, macular degeneration, cataracts, or diabetic retinopathy
- Certain medications including some anti-epileptics, antibiotics, and heart medications
- Ageing — colour discrimination naturally declines slightly with age
- Optic nerve disease or damage
Treatment Options
Inherited colour vision deficiency cannot be cured or treated with medication or surgery. However, awareness of the condition is the most important first step, as many practical strategies can make daily life easier. Colour vision testing — usually with Ishihara plates — is quick and simple and should be included in every child's first eye test.
For those who find their colour deficiency affects daily tasks, tinted lenses and filters (such as EnChroma glasses or Colorlite lenses) may enhance colour contrast for some individuals, though they do not provide normal colour vision and results vary. Smartphone apps that identify colours from the camera can be helpful for matching clothes, interpreting colour-coded labels, or identifying wiring colours in practical tasks.
In terms of career implications, certain professions in the UK require specific colour vision standards. These include the armed forces, police, fire and rescue services, aviation (pilots and air traffic controllers), maritime roles, electrical engineering, and some healthcare positions. Your optometrist can provide a detailed colour vision assessment and, if needed, a report for employers. For children, early identification allows parents and teachers to make simple adjustments — such as labelling coloured pencils and avoiding colour-only instructions — to support learning without disadvantage.
Prevention Tips
- Inherited colour vision deficiency cannot be prevented
- Have children's colour vision tested as part of their first eye test to ensure early awareness
- If you have a family history of colour blindness, mention this to your optometrist
- Protect your eye health generally to reduce the risk of acquired colour vision changes
- Attend regular eye tests as you age, since some colour discrimination changes can be linked to treatable conditions
When to See an Optician
Book an eye test that includes colour vision assessment if you suspect you or your child has difficulty with colours, or if accurate colour vision is required for your career — early diagnosis helps with practical adaptation and career planning.
Key Facts
- Category
- Common condition
- Typically Affects
- All ages (usually present from birth if inherited)
- Key Symptoms
- 6 identified symptoms
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Detecting Colour Blindness (Colour Vision Deficiency)
The following eye tests can help detect signs of colour blindness (colour vision deficiency):
- Standard eye test
- OCT retinal scan
- Visual field test
Protect your vision with a regular eye test
Early detection is key. A routine eye test can identify signs of colour blindness (colour vision deficiency) before symptoms become noticeable. Book yours today.
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