Causes of Glaucoma

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How the eye works:

The eyeball is filled with a watery fluid called aqueous humour, which creates pressure in the eye to give it shape. In healthy eyes, this fluid constantly flows in and out of the eye to nourish it. It drains back into the bloodstream at the same rate that it is produced in order to maintain the correct pressure.

Causes of glaucoma:

In an eye affected by glaucoma, the flow of fluid is blocked. This can happen if the tiny filters that drain fluid from the eye (called the trabecular meshwork) become partially blocked. Or it can happen if the iris moves forward and obstructs the filters. Pressure in the eye builds up and damages the optic nerve and nerve fibres of the retina, leading to glaucoma.

However, the cause of glaucoma is not completely understood, as optic nerve damage can occur even when pressure in the eye is not high. Factors such as poor blood supply to the optic nerve or a weakness in the nerve may affect it.

By the age of 70, about one person in ten has significantly raised eye pressure. Chronic (acute angle) glaucoma also runs in families and is more likely to occur in relatives of people with the disease.

People of Afro-Caribbean origin, very shortsighted people and those with diabetes are at a higher risk of developing open angle glaucoma.