Glaucoma is a common eye condition affecting the optic nerve, which transmits vision from the eye to the brain. Each optic nerve contains more than a million nerve fibres, and these appear to be most vulnerable just where they leave the back of the eye. In untreated glaucoma, these fibres gradually die off, resulting in blurred or blank patches in the field of vision.
There are many different types of glaucoma. Sometimes it results from other eye disease or an eye injury. However, the commonest sort, called primary open angle glaucoma, usually starts in a previously healthy eye.
Primary open angle glaucoma becomes commoner with age, is painless, and doesn't cause other symptoms such as redness, watering etc. Like other types of glaucoma, it is often caused by raised pressure inside the eye, but in some cases can occur even with a normal pressure. Usually a patient can only tell they have it when significant damage has already been done. Unfortunately, there is no treatment which can undo the damage. It is therefore very important to detect glaucoma early, and optometrists are trained to do this as part of an eye check.
Treatment can slow or stop further progression of glaucoma. All current treatments work by lowering the pressure inside the eye, and for most patients, this will mean lifelong eyedrops, administered usually once or twice a day, depending on the type of drop. Where eyedrops are insufficient, surgery can also be carried out to lower the pressure in the eye.
Glaucoma is one of the world’s leading causes of blindness and affects about one person in every 50 over the age of 40.