Schematic diagram of the human eye, with the fovea at the bottom.

The fovea, also known as the fovea centralis, is a part of the eye, located in the center of the macula region of the retina. ^{[1] [2]} The fovea is responsible for sharp central vision, which is necessary in humans for reading, watching television or movies, driving, and any activity where visual detail is of primary importance. The fovea is surrounded by the parafovea belt, and the perifovea outer region:^[2] the parafovea is the intermediate belt where the ganglion cell layer is composed of more than five rows of cells; the perifovea is the outermost region where the ganglion cell layer contains two to four rows of cells, and is where visual acuity is below the optimum. This, in turn, is surrounded by a larger peripheral area that delivers information of low resolution. A human eye. ... Human eye cross-sectional view. ... Human eye cross-sectional view. ... This article or section does not cite its references or sources. ... Reading is a process of retrieving and comprehending some form of stored information or ideas. ... This is a dorsal root ganglion (DRG) from a chicken embryo (around stage of day 7) after incubation overnight in NGF growth medium stained with anti-neurofilament antibody. ... Peripheral vision is a part of vision that occurs outside the very center of gaze. ...

Description

At the center of the fovea there is a pit (termed the "foveal pit") with a diameter of about 0.2 mm, containing a high concentration of cone cells and virtually no rods. ^[1] Compared to the rest of the retina, the cones in the foveal pit are smaller and more densely packed (in a hexagonal pattern), and they are not obscured by a layer of nerve cells or blood vessels; all of this together accounts for the sharp vision associated with them. A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ... Normalised absorption spectra of human cone (S,M,L) and rod (R) cells Cone cells, or cones, are cells in the retina of the eye which only function in relatively bright light. ... Normalised absoption spectra of human rod (R) and cone (S,M,L) cells. ... Human eye cross-sectional view. ... A regular hexagon In geometry, a hexagon is a polygon with six edges and six vertices. ...

Due to the lack of a vitreal blood supply, the fovea must receive its oxygen from the vessels in the choroid, which is across the retinal pigment epithelium and Bruch's membrane. This blood supply alone does not satisfy the metabolic needs of the fovea under conditions of bright light, and the fovea thus exists in a state of hypoxia when under bright illumination. The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye lying between the retina and the sclera. ... The retinal pigment epithelium is the pigmented cell layer just outside the neurosensory retina that nourishes retinal visual cells, and is firmly attached to the underlying choroid and overlying retinal visual cells. ... Bruchs membrane is the innermost layer of the choroid. ... Hypoxia is a pathological condition in which the body as a whole (generalised hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply. ...

Since cones contain the pigmented opsins that allow humans to discriminate color, the fovea is largely responsible for the color vision in humans which is superior to most other mammals'. A rhodopsin molecule in the cell membrane. ... Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths (or frequencies) of the light they reflect or emit. ... Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ... I smoke weed im growing a blue penis dude#REDIRECT penises are cool ...

The foveal pit is not located exactly on the optical axis, but is displaced about 4 to 8 degrees temporal to it. In telecommunication, the term optical axis has the following meanings: 1. ...

The fovea is less than 1% of the retina but takes up over 50% of the visual cortex in the brain. ^[3] The fovea sees only the central two degrees of the visual field, which is roughly equivalent to twice the width of your thumbnail at arm's length. ^[4] Brodmann area 17 (primary visual cortex) is shown in red in this image which also shows area 18 (orange) and 19 (yellow) The visual cortex refers to the primary visual cortex (also known as striate cortex or V1) and extrastriate visual cortical areas such as V2, V3, V4, and V5. ...

Surrounding the foveal pit is the foveal rim, where the neurons displaced from the pit are located. This is the thickest part of the retina.

Since the fovea does not have rods, it is not sensitive to dim lights. Astronomers know this: in order to observe a dim star, they use peripheral vision, looking out of "the side of their eyes". An astronomer or astrophysicist is a person whose area of interest is astronomy or astrophysics. ... Peripheral vision is a part of vision that occurs outside the very center of gaze. ...

The fovea is covered in a yellow pigment called xanthophyll,^[1] with the carotenoids zeaxanthin and lutein (Balashov and Bernstein, 1998), present in the cone axons of the Henle fibre layer.^[1] The pigment area absorbs blue light and is probably an evolutionary adaptation to the problem of chromatic aberration. This article or section does not cite its references or sources. ... Carotenoids are organic pigments that are naturally occurring in plants and some other photosynthetic organisms like algae, some types of fungus and some bacteria. ... Zeaxanthin is one of the two carotenoids contained within the retina. ... Lutein (LOO-teen) is one of over 600 known naturally occurring carotenoids. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Chromatic aberration is caused by the dispersion of the lens material, the variation of its refractive index n with the wavelength of light. ...

See also

• Eye movement
• Eye movement in language reading
• Eye movement in music reading
• Gaze-contingency paradigm

An eye is an organ that detects light. ... The study of eye movement in language reading stretches back almost a thousand years. ... A string trio comprising a pianist, violinist and cellist. ... The gaze-contingency paradigm, also known as the moving window technique, is a method of electronically manipulating a stimulus display—typically of linguistic text—in real-time, automatic response to the location of a readers fixations. ...

Additional images

Horizontal section of the eyeball. Image File history File links Gray869. ...

References

External links