Glaucoma is caused by raised pressure inside the eye. As a result, damage to the optic nerve occurs. Sometimes damage can occur with normal eye pressure if the nerve is already weak. The amount of damage depends on how high the pressure is and how long it lasts. A really high eye pressure can damage the optic nerve in a very short period of time while a lower pressure can cause damage more slowly and if untreated can cause gradual sight loss.

   The main types of glaucoma are: Primary open angle glaucoma (POAG) also known as chronic glaucoma,

Acute angle closure glaucoma and Secondary glaucoma

However there are other types of glaucoma as well which are not so frequent.

 

Primary open angle glaucoma

Primary open angle glaucoma (POAG) is the most common type. The pressure of the eye is raised and that slowly damages vision. The peripheral vision is affected first which is why most people do not notice any changes in the eye sight at the early stages. The centre of the visual field is affected last. In the late stages it feels like looking through a long tube - this is so-called "tunnel vision".

If the rise in pressure is left untreated it may eventually lead to blindness.

There are several risk factors in developing POAG such as: Age, race, family history, diabetes and being short sighted.

The treatment for POAG aims to prevent further damage to the sight by reducing the pressure in the eye. This is usually achieved with eyedrops. It cannot repair or improve damage that may have already been caused by high pressure.

Sometimes, in addition to eyedrops, a special kind of laser treatment can be used to reduce the pressure of the eye. Where eye drops and laser treatment have failed to control the eye pressure then surgery may be considered. This is usually required in about five percent of people who suffer from glaucoma

 

Acute Angle Closure Glaucoma

Acute angle closure glaucoma happens when there is a sudden blockage to the flow of aqueous fluid from the eye. As a result the pressure of the eye rises very quickly to very high levels.

This is nearly always very painful and causes permanent damage to the eyesight if not treated promptly. Most people feel very unwell and can be sick.

Acute glaucoma is an emergency and needs to be treated quickly if sight is to be saved.

Treatment which aims at relieving the pain and the pressure of the eye should be given in hospital.

When the acute event has been brought under control laser treatment will be required which will help drain the fluid away from inside the eye. This is called a “laser iridotomy” which creates a new drainage channel at the front of the eye.

 

Secondary glaucoma

An increase in ocular pressure can develop as a complication of another eye condition or injury.

This can lead to damage to the optic nerve and vision and when it happens it is called secondary glaucoma. The treatment aims at reducing the pressure as well as treating the cause.