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Patient Corner

Eye Anatomy

 

                       

           

Anterior chamber. The space inside the eye between the corneal endothelium (innermost layer of the cornea) and the iris. This space is filled with fluid called the aqueous humor.

 

Aqueous (A-kwee-us), aqueous humor. Clear watery substance filling the space between the cornea and the vitreous. The fluid contains nutrients that nourishes certain structures of the eye. It also plays a role in maintaining the intra ocular pressure (IOP), and in the normal state maintains a fine balance between its production and its drainage.

 

Conjunctiva (kohn-junk-TI-vah). Transparent mucous membrane covering the outer surface of the eyeball. It is continuous with the inner part of the upper and lower eyelid (fornices).

 

Cornea (KOR-nee-ah). This is the transparent structure at the front of the globe. It provides a pathway for light to enter the front part of the eye in order to reach the retina, playing an integral part of the refractive power of the eye.

 

Crystalline lens. The eye’s natural lens is usually a transparent biconvex structure that helps to focus the light entering the eye and thereby helping to focus images onto the retina.

 

Eyelids. These structures help to protect the eye and aids in distributing the tear film over the cornea. The eyelids also contain tear glands and ducts for the normal production and secretion of the tear components.

 

Fovea (FOH-vee-ah). The central indented part of the macula at the back of the globe that is responsible for the sharpest vision. Light entering the eye must be focussed on this part of the retina in order to obtain the sharpest image of an object.

 

Fundus. The posterior pole or the back part of the inside of the eye. Structures include the retina with the macula and the fovea at the centre, and the optic nerve/disc.

 

Iris. The coloured part of the eye that lies behind the cornea and in front of the lens. At the centre of the iris is an opening called the pupil. This controls the amount of light that enters the eye and reaches the retina.

 

Lacrimal gland. A gland that is located at the upper and outer part of the orbit on the outside of the globe. This is the main gland responsible for producing tears.

 

Macula. Small central area of the retina surrounding the fovea.

 

Optic nerve. Also referred to as the optic disc. This nerve is responsible for carrying information of sight from the eye to the brain.

 

Pupil. Opening at the centre of the iris that controls the amount of light entering the eye.

 

Retina. A very thin layer of nerve tissue located on the inside of the globe that is sensitive to light. The light that enters the eye is then converted into information that travels to the visual centre via the optic nerve where this information is then converted into the “images that we see”.

 

Sclera The white outer layer of the eye covered by the conjunctiva. This layer is continuous with the cornea at the front of the globe and the sheath covering the optic nerve at the back.

 

Trabecular meshwork Mesh-like structure inside the eye at the iris-scleral junction of the anterior chamber angle. This structure filters aqueous fluid out of the eye and controls its flow into the canal of Schlemm, prior to its leaving the anterior chamber.

 

Uvea, uveal tract. Pigmented layers of the eye (iris, ciliary body, choroid) that contain most of the intraocular blood vessels.

 

Vitreousvitreous humor. This transparent, colorless gelatinous fills the rear two-thirds of the eyeball, between the lens and the retina. This structure is responsible for maintaining the integrity of the globe.

 

Zonules. Radially arranged fibers that suspend the lens from the ciliary body and hold it in position.