You may have heard of colour blindness but what is it? And how does it really affect people?
Colour blindness is a condition of the eye in which the different wavelengths of light are not properly received by the photoreceptors in the eye.
The eye utilizes cells called cones to pick up red, green, and blue wavelengths of light. These are then compared by the brain to show the bright and colourful world that most people know.
When a person has colour blindness some of these cones do not work properly or don’t work at all leading to an incorrect colour vision.
Most of the time a person’s colour blindness starts at birth as a genetic condition but it can result from an injury or a disease.
There are many different types of colour blindness that range in how strongly they affect vision with 4 (Deuteranomaly, Protanomaly, Protanopia, and Deuteranopia) being categorized into Red-Green colour blindness, 2 (Tritanomaly, and Tritanopia) into Blue-Yellow colour blindness (usually from a resulting injury). There is also the rare condition known as Achromatopsia in which a person can only see in shades of grey.
Optometrists screen for colour blindness in practice, most often using an Ishihara Test. Screening is usually done once, when a child is young, and not at every visit.
Should you ever have difficulty telling apart colour consult your local eye doctor.