Glaucoma is a condition in which the nerves which transmit information from the eye to the brain become damaged. It is often associated with a build-up of pressure in the eye. The eye is filled with fluid which is constantly being replaced. If too much fluid is produced, or if it cannot drain away properly, the pressure inside the eye can increase. In some forms of glaucoma, the pressure inside the eye can become extremely high, but in other forms the pressure may remain normal.
If untreated, glaucoma can cause blindness. Initially peripheral vision is affected but the damage extends if not treated. The damage to the nerve cells cannot be reversed although it is often possible to prevent further damage. The longer the disease is left untreated, the greater the likelihood of damage.

Who is at risk?
People over the age of 40 years are far more likely to have glaucoma than younger people. Also, glaucoma tends to run in families so anyone over 40 with a blood relative who has the disease should have their eyes checked on a regular basis, at least every two years.

What causes glaucoma?
The exact causes of glaucoma are not known. In some cases the drainage network of the eye may not be formed properly, or may become blocked by natural materials or due to injury; in other cases there is no clear cause.