Glaucoma is an eye disease causing damage to the optic nerve.
What is glaucoma?
Glaucoma occurs when the optic nerve at the back of the eye is damaged, often in association with an increase in pressure inside the eye.
There are two main types of glaucoma: primary open angle glaucoma and acute angle closure glaucoma.
In primary open angle glaucoma, the most common form, the optic nerve becomes damaged over time. Often (but not always) this is associated with an increase in eye pressure. A normal eye pressure is necessary to keep the eye healthy and functioning properly. It is regulated by the release of fluid, aqueous humour, which circulates from behind the iris into drainage channels between the iris and the cornea. If the ability to drain the fluid is compromised then fluid can build up and eye pressure will rise and can begin to damage the optic nerve.
Damage to vision occurs very slowly and the first signs may be the loss of some parts of the visual field, most commonly the peripheral, or side vision.
Acute angle closure glaucoma, and some other rare types of glaucoma, is when the drainage system blocks completely. This type of glaucoma occurs with the sudden onset of pain in the eye or brow, blurred, haloed or decreased vision, and nausea or vomiting. It can rapidly lead to blindness in the affected eye if not treated promptly.
Glaucoma can affect young children too - in some cases even before birth. In congenital glaucoma, the drainage openings that allow the normal flow of eye fluid in the anterior eye, between the iris and the cornea, do not properly develop. This results in pressure build-up within the infant’s eye, stretching of the cornea (the clear front surface of the eye) and potential vision loss.
Secondary glaucoma is the result of other eye conditions or diseases, such as eye trauma, some medication, inflammation, or abnormal blood vessel growth as the result of diabetic retinopathy.
Who gets glaucoma?
Glaucoma is a leading cause of blindness. Primary open angle glaucoma is the most common form and mainly affects people over 40 years of age.
People who have diabetes, suffer from migraines or have had an eye injury, are more at risk of developing the disease. A family history of glaucoma increases the risk. Infantile glaucoma can occur from birth or can develop in a child’s early years.
What's the magnitude of the problem?
Globally, glaucoma is the second leading cause of blindness, with 8% of blindness caused by the disease.
Glaucoma is the number one cause of preventable blindness in New Zealand.
With high rates of diabetes and eye trauma in the Pacific, glaucoma is of particular concern to our eye health workers.
How is it treated?
The management of glaucoma focuses on reducing or eliminating the chances of further damage to the eye. This involves lowering the pressure in the eye by slowing down the production of the aqueous humour or improving the ability of the drainage system to drain it.
Existing damage and vision loss cannot be restored. Medication (eye drops); laser treatment and surgery are methods used to bring the pressure in the eye under control and reduce or eliminate the risk of further damage.
Note: This information is general in nature and is not a substitute for specialist medical advice. Have your eyes checked regularly every two years, even if you have not noticed any symptoms or changes.