Glaucoma occurs when the optic nerve, which carries information from your eyes to your brain, becomes damaged. This is usually due to raised pressure in the eye or a weakness in the optic nerve itself. It can come on slowly over a period of time, or suddenly, but both can result in a loss of sight if not treated. The risk of glaucoma increases with age, if anyone else in the family has suffered with the condition, if you are of African origin or are short sighted.
Since glaucoma can be hereditary, it is especially important to have your eyes tested regularly if a close relative suffers from glaucoma. If you are over 40 and a close relative suffers from glaucoma you are eligible for a free eye test paid for by the NHS.
For more information, download a PDF Fact Sheet for Glaucoma from The Eyecare Trust.