The week of March 8-14 is World Glaucoma Week. It aims to raise awareness of glaucoma and will emphasise the fact that half of people currently suffering from the disease are unaware they have the condition. Glaucoma is the third biggest cause of blindness worldwide. It affects around 60 million people, of whom about 4.5 million have become blind. It is common in both developed and developing countries.

Glaucoma is not a single disease entity but a group of conditions characterized by damage to the optic nerve (detected by pathological cupping of the optic disc) and loss of the field of vision. The two main types are primary open-angle glaucoma and primary angle-closure glaucoma. Primary open-angle glaucoma is more frequent in whites and Afro-Caribbeans, while primary angle-closure glaucoma is more common in South-East Asia.

Glaucoma is uncommon among persons under the age of 40, but the prevalence increases with age. Other risk factors include raised pressure inside the eye (intraocular pressure), a positive family history and belonging to a susceptible ethnic group. Primary open-angle glaucoma cannot be prevented, but acute attacks of primary angle-closure glaucoma and more chronic forms of the disease can be prevented by early detection, followed by laser treatment or surgery to the iris. As the early stages of both types of glaucoma are often asymptomatic, patients often present late, particularly in developing countries. Once vision has been lost, regardless of the type of glaucoma, it cannot be restored.