Eye color is a polygenic phenotypic character determined by two distinct factors: the pigmentation of the eye's iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris.

In humans, the pigmentation of the iris varies from light brown to black, depending on the concentration of melanin in the iris pigment epithelium (located on the back of the iris), the melanin content within the iris stroma (located at the front of the iris), and the cellular density of the stroma. The appearance of blue and green, as well as hazel eyes, results from the Tyndall scattering of light in the stroma, a phenomenon similar to that which accounts for the blueness of the sky called Rayleigh scattering. Neither blue nor green pigments are ever present in the human iris or ocular fluid. Eye color is thus an instance of structural color and varies depending on the lighting conditions, especially for lighter-colored eyes.

The genetics and inheritance of eye color in humans is complicated. So far, as many as 15 genes have been associated with eye color inheritance. Some of the eye-color genes include OCA2 and HERC2. The earlier belief that blue eye color is a simple recessive trait has been shown to be incorrect. The genetics of eye color are so complex that almost any parent-child combination of eye colors can occur. However, OCA2 gene polymorphism, close to proximal regulatory region, explains most human eye-color variation.

Most newborn babies who have European ancestry have light-colored eyes. As the child develops, melanocytes (cells found within the iris of human eyes, as well as skin and hair follicles) slowly begin to produce melanin. Because melanocyte cells continually produce pigment, in theory eye color can be changed. Adult eye color is usually established between 3 and 6 months of age, though this can be later. Observing the iris of an infant from the side using only transmitted light with no reflection from the back of the iris, it is possible to detect the presence or absence of low levels of melanin. An iris that appears blue under this method of observation is more likely to remain blue as the infant ages. An iris that appears golden contains some melanin even at this early age and is likely to turn from blue to green or brown as the infant ages.

Changes (lightening or darkening) of eye colors during early childhood, puberty, pregnancy, and sometimes after serious trauma (like heterochromia) do represent cause for a plausible argument stating that some eyes can or do change, based on chemical reactions and hormonal changes within the body.

Optometry: Open Access Journal deals with eyes and related structures which includes such as vision, processing information related to vision. Optometrists are health professionals provide care related to vision. They give a clear idea related to diagnosis, treatment and management of vision. Optometry journal deals with medications, vision tests and abnormalities of eye.

Manuscripts can be submitted online athttps://www.scholarscentral.org/submissions/optometry-open-access.html  or send an email attachment tooptometry@emedsci.com

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Hannah
Journal Co-ordinator
Optometry: Open Access
ISSN: 2476-2075
omoa@emedicalsci.org