Anterior chamber of eyeball

At a glance

English

Anterior chamber of eyeball

Latin (TA2)

Camera anterior bulbi oculi

System

Eye

Region

Head

Side

Paired, left and right

About the anterior chamber of eyeball

The anterior chamber is the front of the two small compartments of the eyeball that hold aqueous humour. Its anterior wall is the inner face of the cornea, lined by the corneal endothelium; its posterior wall is the front of the iris and, through the pupil, the central part of the lens. Around its rim, where the cornea meets the root of the iris, the chamber narrows to a recess called the iridocorneal angle. Through the pupil it opens freely into the posterior chamber, the narrow slit behind the iris.

Aqueous humour is secreted by the ciliary processes into the posterior chamber, flows forward through the pupil into this space and leaves at the angle. There it filters through the trabecular meshwork into the scleral venous sinus (canal of Schlemm) and so into the episcleral veins. A smaller share drains backwards through the ciliary muscle. The balance between production and outflow sets the intraocular pressure, while the fluid also feeds the cornea and lens, which have no blood vessels of their own.

In the centre the chamber is normally about three millimetres deep, though the figure ranges between roughly one and a half and four millimetres. It becomes shallower with age, as the lens thickens, and in long-sighted eyes, which are shorter than average.

Several conditions show up here. When outflow through the meshwork is impaired, pressure rises and the optic nerve head is slowly damaged, which is glaucoma; a shallow chamber, especially one under about two and a half millimetres, makes closure of the angle by the iris more likely. Bleeding into the chamber, usually after a blunt blow, gives a hyphaema, and a layer of pus is a hypopyon. Inflammation of the iris and ciliary body, anterior uveitis, scatters cells and protein in the fluid. Depth is measured with a slit lamp, ultrasound or rotating camera imaging.

Function and supply

Function

Holds circulating aqueous humour, which nourishes the cornea and lens, carries away their waste and helps maintain intraocular pressure and the shape of the front of the eye.