350 million people worldwide experience color vision deficiency. Most don't know it until something goes wrong. An interactive exploration of the data behind the invisible condition.
CVD prevalence varies dramatically across populations — from less than 1% in Fijian males to over 10% among Druze Arabs. The disparity reveals a complex interplay of genetics, geography, and possibly evolutionary selection.
Female CVD is far rarer due to X-linked recessive inheritance — two defective copies are needed. Many studies report no female cases, marked "N/A" above.
Color vision deficiency is not a single condition. It spans a spectrum from mild anomaly to total color absence, each affecting different cone photoreceptors in the retina.
The most common form. Green appears more red, and red-green distinctions collapse. Affects up to 6% of males.
Reds appear darker and shift toward brown or black. Creates dangerous situations with brake lights and warning signals.
Blue-green and yellow-violet confusions. Rare, autosomal dominant — affects both sexes equally.
Complete colour blindness — the world in greyscale. Accompanied by light sensitivity, nystagmus, and severely reduced acuity.
These simulations approximate how a colour-rich scene appears to individuals with different types of CVD. The transforms are based on established colour-science matrices.
CVD is far more than a clinical curiosity. It shapes education, limits careers, and erodes confidence — especially when it remains undiagnosed.
"I always felt anxious during art class because I could never be sure if I was using the right colors. It made me want to avoid those activities altogether."
— Study participant, Chakrabarti (2018)"I wanted to be a pilot, but when I failed the color vision test, I felt like a door had closed before I even had a chance to try."
— Study participant, Chakrabarti (2018)| Profession | Colour vision requirement | Notes |
|---|---|---|
| Aviation (pilots) | Strict | Universal exclusion. UK CAA introduced CAD test allowing some CVD pilots. |
| Railway / transport | Strict | Signal recognition critical. Most jurisdictions enforce testing. |
| Electrical work | Moderate–strict | Wire colour codes essential for safety. Varies by employer. |
| Healthcare | Variable | Some specialties (pathology, dermatology) require it; others don't. |
| Armed forces | Strict | Camouflage detection, signal identification. Often disqualifying. |
| Graphic design | Variable | Not formally restricted but practically challenging without tools. |
Most individuals with CVD are diagnosed only after years of unexplained difficulties. Testing is reliable from age 4–6, yet routine screening remains absent in most school systems worldwide.
Unusual colour choices in drawings. Parents may notice but often attribute it to creativity or preference.
Struggles with colour-coded materials in school. May be mislabelled as inattentive or underperforming. Testing is reliable but rarely conducted.
Repeated confusion in science labs, geography maps, and art class. Peer awareness grows — teasing and embarrassment may increase.
Discovery often comes through occupational screening, a driving test, or an incidental eye exam. By now, career paths may already be narrowed.
Early detection, inclusive design, and systemic awareness can dramatically improve outcomes for people with CVD. These are the key interventions supported by the research.