Learn about the causes of Glaucoma & find a practitioner in Auckland, Hamilton, Bay of Plenty, Wellington, Christchurch, Dunedin to help you overcome Glaucoma within New Zealand.
Glaucoma is a group of eye diseases that affects the optic nerve (the main nerve for vision). Glaucoma occurs when fluid that passes through the space in front of the eye doesn't drain properly. The fluid builds up and increases pressure inside the eye that can lead to vision loss or blindness. Symptoms of glaucoma include sore or red eyes, enlarged pupils, hazy vision or loss of peripheral vision.
There are four main types of glaucoma which can affect both eyes: open angle glaucoma, acute angle closure glaucoma, secondary glaucoma and developmental glaucoma.
Open angle glaucoma (chronic glaucoma) – This is the most common type and develops slowly. The drainage tubes in the eye become blocked preventing fluid in the eye from draining properly. This leads to a build up of pressure (known as intraocular pressure) which can damage the optic nerve and retina nerve fibres.
Acute angle closure glaucoma (acute glaucoma) – This refers to a narrowing of the angle between the iris (the coloured part of the eye) and sclera (the white of the eye). Narrowing can occur rapidly causing a painful pressure in the eye. This type of glaucoma is rare.
Secondary glaucoma – This occurs as a result of an injury to the eye or by a condition known as uveitis.
Developmental glaucoma – Another rare type of glaucoma, this is usually present at birth or shortly after and is an abnormality of the eyeball.
When the eye is healthy, the watery fluid in the eye (known as aqueous humour) flows in and out to provide nourishment and drains into the bloodstream at the same rate as its produced to maintain pressure.
When the drainage tubes that regulate this process become blocked, the aqueous humour fluid can't drain properly and pressure builds causing damage to the optic nerve.
Other causes of glaucoma include:
Symptoms of glaucoma can vary depending on the type you have.
Open angle glaucoma (chronic glaucoma) is a slow process and people are often unaware of any damage to their sight. The outer field, or peripheral field, of vision is the first to be affected and slowly works its way inwards.
Acute angle closure glaucoma (acute glaucoma) is more rapid and symptoms can include:
Symptoms can last for a few hours and each episode damages vision a bit more. It is important to seek medical attention as soon as possible if you have these symptoms.
Secondary glaucoma can be disguised because an injury or other condition triggers it and the symptoms can be explained by the original problem. Secondary glaucoma can cause hazy vision and coloured halos around light sources.
Developmental glaucoma is present at childbirth or shortly after and the child may display the following symptoms:
For most people with glaucoma, eyesight problems develop slowly and therefore realising there is a problem can be difficult. Regular eye tests are important so any problems can be identified and treated early.
If glaucoma is suspected, there are three tests your optician or ophthalmologist can perform:
Tonometry tests – This tests the pressure of the eye and involves anaesthetic and dye placed into the cornea. A blue light held against the eye then measures the intraocular pressure of the eye.
Opthalmoscopy – This optic disc test uses a torch and magnifier to examine the optic nerve.
Perimetry test – This is a visual field test to identify missing areas of vision. A random sequence of lights are shown to test peripheral vision.