Glaucoma is the name for a group of eye conditions where the optic nerve becomes damaged leading to vision deterioration. The damage to the optic nerve can be caused by an increase in pressure within the eye or a weakness in the optic nerve, or both.
If you have glaucoma, your optic nerve is damaged at the point where it leaves your eye.
Sometimes the damage can result from an increase in pressure in your eye. If you have glaucoma, the pressure within your eye can be so high that your optic nerve is damaged and you may begin to lose your sight.
Glaucoma can also result from a weakness in your optic nerve, which can lead to damage even when the pressure in your eye appears to be normal.
In most people who have glaucoma, the condition is caused by both high pressure and a weakness in the optic nerve but to varying extents.
Getting treatment early can help prevent you from losing your sight.
This includes primary open-angle glaucoma, the most common type of glaucoma.
Chronic glaucoma develops very slowly so that any damage to the nerve and eyesight happens gradually.
If the drainage channels through which the fluid flows become blocked, this can cause the pressure within your eye to rise very slowly which can lead to chronic glaucoma.
Another form of chronic glaucoma called normal tension glaucoma can occur even if the pressure in your eye is within the normal range. It's thought that poor blood supply or a weakness in the optic nerve can make the nerve more likely to be damaged.
This is also called closed-angle glaucoma. This type is much less common than chronic glaucoma. It happens when the pressure in your eye rises very quickly. The drainage angle that lies between the cornea (the clear window at the front of your eye) and the iris (the part that gives your eye its colour) narrows suddenly. This prevents the fluid from flowing out of your eye.
Acute glaucoma can be very painful and you need to seek urgent medical attention. It can cause permanent sight damage unless treated quickly.
This can occur as a result of other conditions, such as if you injure your eye or you get repeated inflammation in it. It can also develop after cataract surgery, as a result of using certain medicines (particularly steroid-containing medicines) or if you have diabetes.
This is a very rare condition where a baby is born with glaucoma.
The condition occurs while the baby's sight is still developing. The tissues at the angle of the anterior chamber don't develop properly and this blocks the flow of the fluid out of the eye.
If you have chronic glaucoma, you probably won't notice any symptoms until your sight has deteriorated considerably. This is because the first part of your sight to be affected is the outer or peripheral field of vision. Central vision, used to focus on an object (for example when you're reading), isn't usually affected until much later on in the disease.
Acute glaucoma tends to come on very quickly. Symptoms include:
If you think you're having an attack of acute glaucoma, you need to go to hospital immediately.
It can be difficult to recognise symptoms of congenital glaucoma but if your baby has watering eyes, is very sensitive to light or has cloudy, white, enlarged eyes, make an appointment to see your GP.
Glaucoma is caused by an increase in pressure within your eye or a weakness in the optic nerve, or both. Usually the amount of fluid produced is balanced by the amount draining away, so the pressure in the front part of your eye stays constant. But if fluid (the aqueous humour) in the front part of your eye (the anterior chamber) doesn't drain away you usually see an increase in pressure.
While you can get glaucoma at any age, you're more likely to develop it later in life. Two percent of people over the age of 40 and five percent people over the age of 70 will develop some type of glaucoma. Other factors that can increase your chances of getting glaucoma include the following.
Even though people of African or black Caribbean descent are more at risk for glaucoma, current evidence does not suggest that Indigenous Australians are more at risk than the Australian Caucasian population. However, more research is needed in this area to be sure.
You may not get symptoms of glaucoma until you have significant loss of sight. Therefore, screening tests are important to detect glaucoma. An optometrist (a health professional who examines eyes, tests sight and dispenses glasses and contact lenses) or an ophthalmologist (a medical eye specialist), can do these during a routine sight test.
As glaucoma is more common if you're over 50 (for Caucasians and Asians) or over 40 (for people of African descent) it's important to have an eye test regularly from this age onwards. It's also important to be tested regularly if you're at risk of developing glaucoma, such as if a family member has it or you have diabetes.
An eye test usually takes about 30 minutes. If you wear glasses, take them with you and any medicines you're taking.
There are a number of tests for glaucoma. Your optometrist may:
If your optometrist thinks you may have glaucoma, you will be referred to an ophthalmologist (a doctor who specialises in eye health, including eye surgery) for more tests. These may include a gonioscopy test to look at the area in your eye where the fluid drains out.
Treatment for glaucoma aims to lower the pressure inside your eye to reduce the risk of future sight loss if it hasn't already deteriorated, or prevent any further loss of sight. Treatment can't reverse any existing optic nerve damage, so it won't improve your sight if it has already deteriorated.
Options include medicines, laser treatment and other types of surgery.
Topical medicines (eye drops) are the first line treatment for chronic glaucoma. There are different types of eye drops available including:
Several other types of medicine are available in drop and tablet form, as alternatives or in addition to beta-blockers or prostaglandins. There are also combination eye drops that may make it more convenient if you are using two or more medicines to treat glaucoma.
It's important that you use any prescribed eye drops every day as advised by your doctor to ensure consistent lowered pressure in the eye. If you don't, the pressure in your eye will rise again. You doctor or pharmacist can show you the best way to self-administer eye drops.
As with all medicines, there can be side effects for each type of medicine. Ask your doctor or pharmacist for more information and read the Consumer Medicines Information leaflet for your medicine.
If you think your medicine is causing a side effect, speak to your doctor or pharmacist as soon as possible. They can advise you and, if necessary, your doctor can prescribe a different drop or consider other treatments.
A laser can be used to open the holes in the draining system to help fluid drain out of your eye or stop your eye producing as much fluid.
The procedure is usually quick and causes little discomfort. It can be done under local anaesthesia and you will be able to go home the same day. The success of this type of treatment varies from person to person, and you may need to continue using eye drops after laser treatment.
You may be able to have surgery if medicines and/or laser treatment haven't lowered the pressure in your eye.
There are a range of operations and the most commonly performed is trabeculectomy. In this operation a tiny opening is created in your eye wall to allow fluid to escape under the thin lining of the white of your eye (the conjunctiva) and be absorbed back into your bloodstream. You may have the operation under local or general anaesthesia.
If you're over 50 (for Caucasians and Asians) or over 40 (for people of African descent), it's important to have regular eye tests to check for the early signs of glaucoma. If you have a family history of glaucoma, it's important to be tested regularly from the age of 35.
Royal Australian and New Zealand College of Ophthalmologists
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Last Updated: 30 May 2013
Tags: glaucoma, eye test, eye health
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