It is possible to divide glaucoma into two main categories, open-angle and closed-angle. The angle refers to the area between the iris and cornea which fluid (aqueous humour) must flow through to drain via the tiny channels of the trabecular meshwork.

Closed-angle glaucoma symptoms can develop quite quickly and are often painful, with the onset of visual loss being very progressive. Because of the discomfort and obvious deterioration in vision, suffers are more likely to seek medical attention.

Open-angle glaucoma, also known as chronic glaucoma, progresses at a much slower rate than closed-angle glaucoma. The loss of vision often occurs gradually over a long period of time and to such a degree that it can often go unnoticed until the disease is quite advanced.

Open-angle glaucoma is often caused by an increase in pressure within the eye which results in damage to the optic nerve at the back of the eye; it is painless and the only symptom is the creeping deterioration in the visual field which may only be noticed when the disease is quite advanced. If it is left untreated, open-angle glaucoma can cause permanent damage and blindness.

Glaucoma management involves the lowering the intraocular pressure (IOP) to a level that will lessen any further optic nerve damage. Treatments include medication (usually prescribed eye drops), laser surgery or conventional surgery.

There are several different medications and surgical procedures available and factors such as the age of the patient, the severity of the condition and other risk factors will help determine the correct course of treatment.