Eye Health

Updated 25 July 2018

Glaucoma: Background physiology

Glaucoma results from pressure within the eye that damages the retina.

The anatomical structures of the eye involved in glaucoma are the ciliary body, the anterior chamber, the anterior chamber angle, and the optic disc.  

Aqueous humor (the fluid within the eye) is produced by structures in the ciliary body. This fluid then circulates to a space in the front of the eye (anterior chamber).

Here, it leaves the inside of the eye via the anterior chamber angle. 

The balance between the production and drainage of the fluid is important in maintaining a normal pressure within the eye.  

How does glaucoma cause damage to the eye?
In individuals with glaucoma, there’s an impairment in the drainage of the fluid in the eye.

This results in a build-up of fluid, which is believed to increase the pressure within the eye (intraocular pressure). 

This increase in pressure causes damage to a structure in the back of the eye called the optic disc. This disc forms the front portion of the optic nerve – the very important connection between the eye and the brain. 

Damage to this structure can affect many different functions, including the ability to see clearly (for example, while you read), the ability to see well in low light conditions (for example, when driving at night), and the ability to see the area around you while looking straight (your peripheral vision). 

Reviewed by ophthalmologist Dr Tshilidzi van der Lecq. MBChB (UCT), Mmed (Ophth), FC Ophth (SA). March 2018.


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Megan Goodman qualified as an optometrist from the University of Johannesburg. She has recently completed a Masters degree in Clinical Epidemiology at Stellenbosch University. She has a keen interest in ocular pathology and evidence based medicine as well as contact lenses.

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