Glaucoma results from an abnormal increase in pressure inside the eye. Raised pressure leads to injury to the optic nerve and progressive loss of peripheral vision. As a result, without screening programs for glaucoma, visual loss is not noted until at a later stage. The majority of cases are known as "primary open angle glaucoma" (POAG) whereby the pressure in the eye increases slowly and without pain over a period of some years. Acute, or "primary angle closure" (PAC) glaucoma, on the other hand, may develop suddenly and painfully. If caught at an early stage, either type of glaucoma can be controlled, with no permanent damage to sight, by the use of special lifetime eye drops that reduce the pressure. Some estimates show that over 200,000 people in the UK are living with the permanent effects of the disease due to the fact that it was not treated in time. Glaucoma monitoring represents a logistical exercise, and because patients generally require at least 2 visits each year with visual field testing in order to identify those patients at greatest risk of progression, increased resources are urgently required in order to handle the capacity issues that affects many departments in the UK at present.

Optic disc in glaucoma