It consists of the sclera and cornea, which are continuous with each other. Their main functions are to provide shape to the eye and support the deeper structures. The fibrous layer of the eye is the outermost layer. Each of these layers has a specialised structure and function. The eyeball is formed by three layers - fibrous, vascular and inner. In this article, we shall consider the anatomy of the eyeball in detail, and its clinical correlations. It lies in a bony cavity within the facial skeleton - known as the bony orbit.Īnatomically, the eyeball can be divided into three parts - the fibrous, vascular and inner layers. The eyeball is a bilateral and spherical organ, which houses the structures responsible for vision. If the drainage of aqueous humor is obstructed, a condition known as glaucoma can result. The aqueous humor is produced constantly, and drains via the trabecular meshwork, an area of tissue at the base of the cornea, near the anterior chamber. The chambers are filled with aqueous humor – a clear plasma-like fluid that nourishes and protects the eye. The anterior chamber is located between the cornea and the iris, and the posterior chamber between the iris and ciliary processes. There are two fluid filled areas in the eye – known as the anterior and posterior chambers. In old age, the lens can become opaque – a condition known as a cataract. The shape of the lens is altered by the ciliary body, altering its refractive power. The lens of the eye is located anteriorly, between the vitreous humor and the pupil. Holds the layers of the retina in place.Contributes to the magnifying power of the eye.The vitreous body has three main functions: It is marked by a narrow canal which runs from the optic disc to the lens – the hyaloid canal. The vitreous body is a transparent gel which fills the posterior segment of the eyeball (the area posterior to the lens). The area that the optic nerve enters the retina is known as the optic disc – it contains no light detecting cells. It is the area responsible for high acuity vision. The macula contains a depression called the fovea centralis, which has a high concentration of light detecting cells. It is yellowish in colour, and highly pigmented. The centre of the retina is marked by an area known as the macula. The optic part of the retina can be viewed during ophthalmoscopy. Posteriorly and laterally, both layers of the retina are present.

It is located posteriorly and laterally in the eye.Īnteriorly, the pigmented layer continues but the neural layer does not – this is part is known as the non-visual retina. Neural (inner) layer – consists of photoreceptors, the light detecting cells of the retina.It continues around the whole inner surface of the eye. It is attached to the choroid and supports the choroid in absorbing light (preventing scattering of light within the eyeball). Pigmented (outer) layer – formed by a single layer of cells.The inner layer of the eye is formed by the retina its light detecting component.

Vascular tunic