The Structure of the Eye

The eye is shaped like a ball. Its tough white outer coat is called the sclera and its surface is covered by a thin skin (the conjunctiva). The outer coat is clear at the front of the eye and this area is called the cornea.

Behind the cornea is the iris - the coloured part of the eye - with the pupil forming a hole in its centre.

The space between the cornea and the iris is filled with a clear fluid, called 'aqueous humour', which maintains the pressure in the eye (the intraocular pressure).

The pressure is determined by a balance between the fluid entering and leaving the eye.