Open and Closed Iridocorneal Angles
The eye is made up of two chambers (anterior and posterior) that are filled with a clear fluid called aqueous humour which nourishes the eye, maintains its natural shape and optical properties as well as determines its intra-ocular pressure. This pressure is maintained by the balance in the production and drainage of the aqueous humour. The iridocorneal angle is the angle formed by the iris (coloured part of the eye) and cornea (transparent, dome-shaped layer covering the eye) to allow the drainage of the aqueous humour from the eye.
Anatomic abnormalities such as the narrowing or closing of the iridocorneal angle causes difficulty in drainage of aqueous humour and increases the intra-ocular pressure. Elevated intra-ocular pressure can lead to glaucoma. Depending on the angle made by the iris and cornea, this glaucoma can be categorised as either open or closed.
Open angle glaucoma: The angle between the iris and cornea appears wide and open as it normally should, but the drainage of aqueous humour is reduced.
Closed angle glaucoma:The angle between the iris and cornea is closed resulting in reduced drainage of aqueous humour.