Glaucoma

Glaucoma develops when the optic nerve at the back of the eye becomes progressively damaged. In many cases, this is associated with increased pressure inside the eye, known as intraocular pressure. The eye continuously produces a clear fluid called aqueous humour, which normally drains through specialised channels. If this fluid does not drain efficiently, pressure can increase and place additional stress on the optic nerve. However, glaucoma can also occur when eye pressure falls within the statistically normal range, meaning pressure is an important risk factor rather than the sole cause of the disease.

The most common form is primary open-angle glaucoma, which usually develops slowly as drainage becomes less efficient. Because early peripheral vision loss can be subtle, people may remain unaware of the condition for years. Other forms include angle-closure glaucoma, in which the drainage angle becomes obstructed, and secondary glaucoma caused by another eye condition, injury or certain medications. Some forms of glaucoma can also be present from birth or develop during childhood, although these are much less common.

The likelihood of developing glaucoma generally increases with age, while family history and genetics can substantially influence risk. Certain medical and eye conditions, previous eye injuries and long-term corticosteroid use can also increase susceptibility in some people. Importantly, optic nerve damage caused by glaucoma cannot currently be reversed. Detecting the condition before substantial vision is lost is therefore particularly important, as appropriate management can often slow or prevent further damage.