What does deuteranope mean?
A deuteranope is a person with deuteranopia, the most widespread form of red-green colour vision deficiency. The condition stems from the absence or malfunction of the medium-wavelength (M) cone cells in the retina, which are normally responsible for perceiving green light. As a result, a deuteranope has difficulty distinguishing reds from greens; greens may appear tan or beige, and reds tend toward brownish-yellow, though blue and yellow vision remains intact. The trait is far more common in men than women because it is carried on the X chromosome — roughly one in twelve males versus about one in two hundred females. The term belongs chiefly to medical and scientific registers, alongside its sibling terms protanope and tritanope for other types of colour blindness. It matters practically in fields such as design, transport signage, and workplace accessibility, where colour choices must remain legible to deuteranopes.
nounA person who has deuteranopia, a form of red–green colour blindness in which sensitivity to green light is reduced or absent due to a missing or abnormal M-cone pigment.
- A person affected by deuteranopia, the most common form of red-green colour vision deficiency, in which green-sensitive cone cells are absent or defective.
"As a deuteranope, he could not distinguish the ripe red apples from the green ones on the tree."
"The designer tested every palette with a colour-blindness simulator to make sure a deuteranope could still read the chart."
"Because his father was a deuteranope, Marcus learned early to navigate traffic lights by position rather than colour."
Regular plural formation; standard in scientific and general usage.
"Roughly six percent of males are deuteranopes."
A deuteranope doesn't simply see the world in grey — greens shift toward beige, reds toward brownish-yellow, and roughly one in twelve men carries this exact genetic quirk.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of deuteranope
The word combines the Greek-derived prefix 'deutero-', meaning second, with '-anope', from Greek 'an-' (without) and 'ops' or 'ōps' (eye), reflecting that the second of the three cone systems is missing. It was coined in the late nineteenth century within the developing science of colour vision, when physiologists first classified colour deficiencies according to which receptor type was deficient. Related coinages include deuteranopia, deuteranomaly, and the parallel terms protanope and tritanope built on the same Greek roots.
Word family
Usage notes
A clinical and technical term used mainly in medicine, optometry, psychology, and accessibility discussions; in everyday speech, 'colour-blind' is more common. It refers specifically to a person, while 'deuteranopia' names the condition itself.
Don't confuse with
A protanope has reduced sensitivity to red light (missing L-cone function), whereas a deuteranope has reduced sensitivity to green light (missing M-cone function).
A tritanope has extremely rare blue–yellow colour blindness affecting S-cones, whereas a deuteranope has red–green colour blindness affecting M-cones.