Anterior segment of eyeball

Anterior Segment of the Eyeball

The anterior segment or anterior cavity is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens.

• Within the anterior segment are two fluid-filled spaces:
• the anterior chamber between the posterior surface of the cornea (also called the endothelium) and the iris.
• the posterior chamber between the iris and the front face of the vitreous.

Anatomy

Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. The cornea, with the anterior chamber and lens, refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power.

Iris

The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina.

Ciliary Body

The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor.

Lens

The lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina.

Function

The anterior segment of the eyeball plays a crucial role in vision by refracting the light that enters the eye onto the lens. The cornea and lens help to focus the light onto the retina, which then sends signals to the brain to form a visual image.

Clinical significance

Diseases of the anterior segment of the eye can cause a range of symptoms and can affect vision. These include corneal ulcer, glaucoma, cataract, and iritis.

See also

• Posterior segment of the eyeball
• Human eye