The yellow spot is a small depression
forming a shallow pit in the retina
at the back of each eye in the human body. It is slightly yellow in apperance
and so was first called the "Yellow Spot" or "Macula
Lutea" of Sömmerring (the scientist who first discovered
and documented it).
As is true of many terms in anatomy, the term "yellow spot"
is another word for macula
lutea or fovea:
Different terms are used in different texts but the meaning is the same.
Because it contains a large number of the light-sensitive photo-detector
cells called cones,
the yellow spot ("macula lutea", or "fovea")
is the area of greatest acuity of vision.
This means that when an eye is directed at an object, the part of the
image of that object formed on the retina that falls onto the fovea is
the part of the image that will be perceived in the greatest detail.
The existance of such an area is only known to occur in humans, the quadrumana
(a group of primates comprising apes and monkeys), and some saurian reptiles.
The subject of visual (also known as "physiological") optics
is a key component of many courses within the fields of both biology and
physics. It is also an essential consideration in the design of displays
and control units used in many applications from televisions and mobile
telephones to advanced aircraft. In the context of engineering "visual
optics" is one of several medical and psychological topics in the
important area of "Human Factors". |
