Epidemiology
Color blindness affects a significant number of people, although exact proportions vary among groups. In Australia, for example, it occurs in about 8 percent of males and only about 0.4 percent of females. Isolated communities with a restricted gene pool sometimes produce high proportions of color blindness, including the less usual types. Examples include rural Finland, Hungary, and some of the Scottish islands. In the United States, about 7 percent of the male population – or about 10.5 million men – and 0.4 percent of the female population either cannot distinguish red from green, or see red and green differently from how others do (Howard Hughes Medical Institute, 2006). More than 95 percent of all variations in human color vision involve the red and green receptors in male eyes. It is very rare for males or females to be "blind" to the blue end of the spectrum.
| Males | Females | Total | References | |
|---|---|---|---|---|
| Red–green (Overall) | 7 to 10% | — | — | |
| Red–green (Caucasians) | 8% | — | — | |
| Red–green (Asians) | 5% | — | — | |
| Red–green (Africans) | 4% | — | — | |
| Monochromacy | — | — | — | |
| Rod monochromacy (dysfunctional, abnormally shaped or no cones) | 0.00001% | 0.00001% | — | |
| Dichromacy | 2.4% | 0.03% | 1.30% | |
| Protanopia (red deficient: L cone absent) | 1% to 1.3% | 0.02% | — | |
| Deuteranopia (green deficient: M cone absent) | 1% to 1.2% | 0.01% | — | |
| Tritanopia (blue deficient: S cone absent) | 0.001% | 0.03% | — | |
| Anomalous Trichromacy | 6.3% | 0.37% | — | |
| Protanomaly (red deficient: L cone defect) | 1.3% | 0.02% | — | |
| Deuteranomaly (green deficient: M cone defect) | 5.0% | 0.35% | — | |
| Tritanomaly (blue deficient: S cone defect) | 0.01% | 0.01% | — |
Read more about this topic: Color Blindness