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In this section, we provide some basic information about the eye as well as the most common signs, symptoms and disorders of the Retina and Vitreous. We eagerly await your feedback so as to provide only the most useful information to our valuable patrons. Choose a topic below to learn more:

The Eye


Iris Pupil Cornea Posterior Chamber Anerior Chamber Ciliary Muscle Zonular Fibres Lens Retina Choroid Sclera Optic Disc Optic Nerve Vitreous Humor Fovea

Optic Nerve
The Optic Nerve, also called Cranial Nerve II, is the nerve that transmits visual information from the Retina to the Brain.


Optic Disc
The Optic Disc or Optic Nerve head is the point in the eye where the optic nerve fibers leave the retina. Due to absence of light sensitive rods and cones of the retina at this point, it is not sensitive to light and thus is also known as "The Blind Spot" or "Anatomical Blind Spot". The optic nerve head in a normal human eye carries about 1 million neurons from the eye towards the brain.


Sclera
The Sclera is the (usually) white outer coating of the eye made of tough fibrin connective tissue, which gives the eye its shape and helps to protect the delicate inner parts.

In children, it is thinner and shows some of the inlying blueness.


Choroid
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 Choroid provides oxygen and nourishment to the outer layers of the retina.


Zonular Fibers
The Zonules hold the lens in place and function to change the focusing power of the eye by changing the tension of the zonules by contraction and relaxation of the ciliary muscle.



Iris
The most visible portion of the eye, giving the eye its characteristic color. The iris consists of pigmented fibrovascular tissue known as a Stroma. The stroma connects a sphincter muscle (Sphincter Pupillae), which contracts the pupil and a set of Dialator Muscles (Dilator Pupillae) which open it. The iris and ciliary body together are known as the anterior uvea. Just in front of the root of the iris is the region through which the aqueous humour constantly drains out of the eye, with the result that diseases of the iris often have important effects on intraocular pressure and indirectly on vision.


Pupil
In the eye, the pupil is the opening in the middle of the iris. It appears black because most of the light entering is absorbed by the tissues inside the eye.


Cornea
The Cornea is the transparent front part of the eye that covers the iris, pupil and anterior chamber, providing most of an eye's optical power. Together with the lens, the cornea refracts light and as a result, helps the eye to focus. The cornea contributes more to the total refraction than the lens does. Transparency, Avascularity and Immunologic privilege makes the cornea a very special tissue.


Anterior Chamber (filled with Aqueous Humour)
The Anterior Chamber is the fluid-filled space inside the eye between the iris and the cornea's innermost surface, the endothelium. Aqueous humor is the fluid that fills the anterior chamber.


Ciliary Muscle
The Ciliary Muscle is a smooth muscle that affects zonules in the eye (fibers that suspend the lens in position during accommodation), enabling changes in lens shape for light focusing.



Lens
The Lens or Crystalline Lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to focus on the retina. Its function is thus similar to a man-made optical lens. Opacification of this lens is termed as “Cataract”.


Vitreous Humor
Vitreous Humor is the clear aqueous solution that fills the space between the lens and the retina of the vertebrate eyeball. The solution is 99% water, but has a gelatinous viscosity two to four times that of water. The primary purpose of the vitreous humour is to provide a cushioned support for the rest of the eye, as well as a clear unobstructed path for light to travel to the retina.


Fovea
The Fovea, a part of the eye, is a spot located in the center of the Macula. 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.


Retina
The Retina is a thin layer of neural cells that lines the back of the eyeball of vertebrates and some cephalopods. In embryonal development, the retina and the optic nerve originate as outgrowths of the brain. Hence, the retina is part of the Central Nervous System (CNS). It is the only part of the CNS that can be imaged directly.

The vertebrate retina contains Photoreceptor Cells (rods and cones) that respond to light; the resulting neural signals then undergo complex processing by other neurons of the retina. The retinal output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve. Several important features of visual perception can be traced to the retinal encoding and processing of light.