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The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens , the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power .
The iris consists of two layers: the front pigmented fibrovascular layer known as a stroma and, behind the stroma, pigmented epithelial cells.. The stroma is connected to a sphincter muscle (sphincter pupillae), which contracts the pupil in a circular motion, and a set of dilator muscles (dilator pupillae), which pull the iris radially to enlarge the pupil, pulling it in folds.
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 ...
The anterior segment is made up of the cornea, iris and lens. 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.
Together, the cornea and lens refract light into a small image and shine it on the retina. The retina transduces this image into electrical pulses using rods and cones. The optic nerve then carries these pulses through the optic canal. Upon reaching the optic chiasm the nerve fibers decussate (left becomes right). The fibers then branch and ...
A refractive cornea type eye of a human. The cornea is the clear domed part covering the anterior chamber of the eye. In the eyes of most mammals, birds, reptiles, and most other terrestrial vertebrates (along with spiders and some insect larvae) the vitreous fluid has a higher refractive index than the air. In general, the lens is not spherical.
The pupil is the central opening of the iris on the inside of the eye, which normally appears black. The grey/blue or brown area surrounding the pupil is the iris. The white outer area of the eye is the sclera. The central outermost transparent colorless part of the eye (through which we can see the iris and pupil) is the cornea.
The lens is located towards the front part of the vertebrate eye, called the anterior segment, which includes the cornea and iris positioned in front of the lens. The lens is held in place by the suspensory ligaments (Zonule of Zinn), [1] attaching the lens at its equator to the rest of the eye [2] [3] through the ciliary body.