Search results
Results From The WOW.Com Content Network
The cornea is transparent and more curved and is linked to the larger posterior segment, composed of the vitreous, retina, choroid and the outer white shell called the sclera. The cornea is typically about 11.5 mm (0.45 in) in diameter, and 0.5 mm (500 μm) in thickness near its centre.
The sclera, [note 1] also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective outer layer of the eye containing mainly collagen and some crucial elastic fiber. [2] In the development of the embryo, the sclera is derived from the neural crest. [3]
Maintains the intraocular pressure and inflates the globe of the eye. It is this hydrostatic pressure that keeps the eyeball in a roughly spherical shape and keeps the walls of the eyeball taut. Provides nutrition (e.g. amino acids and glucose) for the avascular ocular tissues; posterior cornea, trabecular meshwork, lens, and anterior vitreous.
The anterior segment or anterior cavity [1] is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens. [2] [3] Within the anterior segment are two fluid-filled spaces: the anterior chamber between the posterior surface of the cornea (i.e. the corneal endothelium) and the ...
Light entering the eye is refracted as it passes through the cornea. It then passes through the pupil (controlled by the iris) and is further refracted by the lens. The cornea and lens act together as a compound lens to project an inverted image onto the retina. S. Ramón y Cajal, Structure of the Mammalian Retina, 1900
An organism's "eye color" is actually the color of one's iris, the cornea being transparent and the white sclera entirely outside the area of interest. Melanin is yellowish to dark hazel in the stromal pigment cells, and black in the iris pigment epithelium, which lies in a thin but very opaque layer across the back of the iris.
When a cornea is needed for transplant, as from an eye bank, the best procedure is to remove the cornea from the eyeball, preventing the cornea from absorbing the aqueous humor. [ 10 ] There is a global shortage of corneal donations, severely limiting the availability of corneal transplants across most of the world.
The fibrous tunic, also known as the tunica fibrosa oculi, is the outer layer of the eyeball consisting of the cornea and sclera. [4] The sclera gives the eye most of its white color. It consists of dense connective tissue filled with the protein collagen to both protect the inner components of the eye and maintain its shape. [5]