The Endemic Part 2

Different endemic though. Achromotopsia. A rare color blindness that is a form of monchromacy, or the inability to distinguish between all colors, not just red/green (which is just one of many different color blindnesses). Without getting into too much detail, inside the eyes there are rods, which are responsible for low light vision, and cones, which are responsible for daylight and color vision. There are a few "cone systems" in the eye that are each responsible for different colors. In normal monochromacy, there is only one cone system in the eye, so distinguishing between different colors is impossible. In Achromotopsia, there are no cone systems. So not only is color impossible to see, but normal intensity light can be painful. Fortunately, achromotopsia is extremely rare. Except for the Pingelap in The Federated States of Micronesia. It is an edemic there, which means that the infection (in the sense that it is commonly used) or disorder is maintained with no external inputs. Such as chicken pox in the U.S. or malaria in Africa. Apparently the island was devastated by a storm in the 18th century and one of the surviving men had the condition. Now, 1/12 of the population of the island has the disorder that they call maskun, and 30% of the population carries the genes for it.

1 out of 33,000 people in the U.S. suffer from maskun. Many lead normal lives with the aid of darkened lenses.