Glaucoma is an eye disorder in which the fluid pressure inside the eye causes progressive damage to parts of the optic nerve. The pressure usually increases when there is inadequate drainage of fluid from inside the eye. A gradual, but permanent loss of vision occurs unless the condition is treated.
Are there different types of Glaucoma?
There are three main types:
Acute Glaucoma – when a rapid blockage of the drainage system occurs. With little or no warning, the eye becomes red and very painful, and misty vision may cause halos around lights.
Chronic Glaucoma – when the pressure slowly increases over several months or years. No symptoms are present in the early stages and severe loss of vision may occur before a person realises that something is wrong.
Secondary Glaucoma – results when injury, inflammation, or tumour blocks the drainage canals.
How does glaucoma affect sight?
If the pressure is raised for a period of time, some fibres of the optic nerve, which conduct impulses from light sensitive cells of the retina to the brain, are destroyed. Because the loss of vision occurs slowly and away from the direct line of clearest vision, a person with glaucoma may not notice any changes to their sight until a considerable reduction to the field of vision has occurred. Without treatment, this loss continues until the eye is blind.
How is glaucoma detected?
Your Optometrist will check for glaucoma as part of a regular eye examination. Tests include assessing the appearance of the optic nerve head, measuring the pressure in the eye and analysing the complete field of vision. If any signs of glaucoma are detected, you will be referred to an Ophthalmologist (eye doctor) for further evaluation.
Can sight which is lost be regained?
No – treatment aims to prevent any further loss of vision.
EARLY DIAGNOSIS IS ESSENTIAL – VISION ALREADY LOST CANNOT BE REGAINED.
Who gets glaucoma?
Anyone may develop glaucoma, but the risk increases as age increases and the risk is higher if close relatives have glaucoma. About 2 in 100 people over the age of 40 have glaucoma.
Should vision be checked regularly?
Everyone, especially those over 40 years old, should have their eyes examined regularly to check that no eye health problems are present or developing.
A thorough examination will ensure that you continue to have efficient, comfortable vision and healthy eyes. Don’t forget that most people begin to have difficulty with near vision in their 40’s. This is a normal ageing process solved by using spectacles to help with close work. Checks for glaucoma are part of a routine eye examination. These are particularly important for people over 40 years, or where there is a family history of glaucoma.
For more information see links below:
www.glaucoma.org.nz Glaucoma New Zealand
http://www.aao.org American Academy of Ophthalmology