Macula

The macula or macula lutea (from Latin macula, "spot" + lutea, "yellow") is an oval-shaped highly pigmented yellow spot near the center of the retina of the human eye. It has a diameter of around 1.5 mm and is often histologically defined as having two or more layers of ganglion cells. Near its center is the fovea, a small pit that contains the largest concentration of cone cells in the eye and is responsible for central, high resolution vision. The macula also contains the parafovea and perifovea.

Because the macula is yellow in colour it absorbs excess blue and ultraviolet light that enter the eye, and acts as a natural sunblock (analogous to sunglasses) for this area of the retina. The yellow colour comes from its content of lutein and zeaxanthin, which are yellow xanthophyll carotenoids, derived from the diet. Zeaxanthin predominates at the macula, while lutein predominates elsewhere in the retina. There is some evidence that these carotenoids protect the pigmented region from some types of macular degeneration.

Structures in the macula are specialized for high acuity vision. Within the macula are the fovea and foveola which contain a high density of cones (photoreceptors with high acuity).

Read more about Macula:  Clinical Significance

Other articles related to "macula":

Macula (disambiguation)
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Macula Of Saccule
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Tubuloglomerular Feedback - Background
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Macula - Clinical Significance
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