Glaucoma can be regarded as a group of diseases that have as a common end-point a characteristic optic neuropathy which is determined by both structural change and functional deficit. The medical understanding of the nature of glaucoma has changed profoundly in the past few years and a precise comprehensive definition and diagnostic criteria are yet to be finalised. There are several types of glaucoma, however, the two most common are primary open angle glaucoma (POAG), having a slow and insidious onset, and angle closure glaucoma (ACG), which is less common and tends to be more acute.


The number of persons estimated to be blind as a result of primary glaucoma is 4.5 million, accounting for slightly more than twelve per cent of all global blindness. Risk factors are those limited to the onset of disease and those associated with progressive worsening in already established disease. The primary risk factors that are linked to the individual and the onset of the disease are age and genetic predisposition. The incidence of POAG rises with age and its progression is more frequent in people of African origin. ACG is the common form of glaucoma in people of Asian origin.

Types of glaucoma

  1. Primary open angle glaucoma (POAG) is the most common type of glaucoma. It’s a chronic condition which means damage to your optic nerve occurs as well as gradual changes to your sight.
  2. Acute angle closure glaucoma happens when your eye pressure rises very suddenly. It’s very painful and can cause permanent damage to your sight if it’s not treated quickly.
  3. Secondary glaucoma occurs as a result of another eye condition, eye injury or inflammation, eye surgery complications, diabetes and the use of certain medications.
  4. Congenital glaucoma is a very rare condition that affects young babies. It’s usually diagnosed in early years and managed by specialist clinics.

Video animation of Glaucoma

Video animation of Glaucoma

Source: National Eye Institute (NEI)​

Prevention and treatment

There is little known about primary prevention of glaucoma; however, there are effective methods of medical and surgical treatment if the disease is diagnosed in its early stage. Through appropriate treatment, sight may be maintained; otherwise the progression of the condition leads eventually to severe restriction of the visual field and irreversible blindness.

All treatment for glaucoma aims to lower your eye pressure to prevent damage to your optic nerve and your sight. Treatment to lower your eye pressure usually starts with eye drops, and for most people with glaucoma. This is all the treatment needed.

Sometimes, laser treatment or surgery may also be needed to help control your eye pressure and prevent sight loss.

Your ophthalmologist (hospital eye doctor) will be able to discuss the best treatment for you.

Over time the disease develops into a loss of peripheral (side) vision. If glaucoma is untreated it could advance to later stages where central vision narrows to "tunnel" vision, or it may result in blindness. Early detection and treatment is essential to prevent severe vision loss or blindness.

There is no treatment to restore sight loss caused by glaucoma.

The number of people estimated to be blind as a result of primary glaucoma is 4.5 million, accounting for slightly more than twelve per cent of all global blindness.