Medical, Laser and Surgical Management
What is Glaucoma?
Glaucoma is a disease affecting the optic nerve, which carries images from the retina to the brain.
In most cases of glaucoma the normal fluid pressure within the eye (known as intraocular pressure (IOP)) slowly raises putting pressure on these nerve fibres. Untreated this may lead to loss of vision as the fibres die, ultimately leading to blindness.
The disease usually affects both eyes although the pressure often builds up in one eye first.
What are the causes of raised intraocular pressure?
The fluid within the eye (known as aqueous humor) helps to bathe and nourish the lens, iris, and cornea. It is produced by the tissues around the lens and drains out of the eye and into the bloodstream. This happens through a tiny network of drainage canals near the iris called the trabecular meshwork.
With the most common form of glaucoma (open-angle glaucoma) the fluid drains out of the eye too slowly. There is another form (closed-angle glaucoma) in which these drainage canals become blocked altogether, although this is far less common.
Open-angle? Closed-angle? What is the difference?
This refers to the angle where the iris meets the cornea.
• In open-angle glaucoma the angle is as wide as it should be and the entrance to the drainage system is clear. The problem is that the system is blocked on the inside in the same way that the pipe below a plug-hole can clog. This accounts for approximately 90% of all glaucoma cases.
Open-angle glaucoma is a long-term condition which progresses slowly. The drainage canals become more and more clogged and the pressure increases gradually. Usually this build up happens without any pain or discomfort and it may take years before there is any visual change. When this does occur it is likely to be restricted to peripheral (around the edge) vision. Often this goes unnoticed until there is a lot of nerve damage and the field of vision is significantly narrowed.
• Closed-angle glaucoma is an acute condition with a sudden deterioration and consequently the symptoms are usually very noticeable. Closed-angle glaucoma means that the angle between the iris and cornea is not as open as it could be. With ageing our natural lens thickens further narrowing the drainage angle. This can be likened to putting the plug in a plug-hole. It can be helpful to treat patients at risk of angle closure glaucoma with Laser treatment to avoid the need for emergency treatment.
Is glaucoma common?
Very. It affects approximately half a million people in the UK alone and many have lost their sight as a result. Given the nature of the disease it is believed that many people are affected without even realising it.
It is the third leading cause of blindness after catatacts and macular degeneration. Unlike cataracts though blindness caused by glaucoma is irreversible.
Can my glaucoma be treated?
The simple answer is that in most cases treatment is possible.
There are various options available and numerous different drugs available. Because glaucoma is a lifelong condition it is likely that a drug may lose its effectiveness and therefore an alternative may need to be prescribed. In any event, the goal of the doctor is to lower the pressure in your eye either by decreasing the amount of fluid produced or by increasing the drainage.
Will I need surgery?
Possibly, but it does depend on how your condition progresses. If medication does not help, you may need more direct action and this would be either laser treatment or surgery.
Can I do anything to help beat glaucoma?
As yet there is little scientific evidence to suggest that a change of diet or behaviour will help. However some sufferers believe that in addition to their medication regular exercise, eating vegetables (such as broccoli, spinach, or carrots), and not smoking has helped. In any event you should continue to take the medication prescribed.
Recent research suggests Vitamin B3 may protect against glaucoma, and aid nerve health and even recover lost function.
Glaucoma can run in families. If you have glaucoma please advise your children to have their eye pressures checked with a local optician.
Will it affect my ability to drive?
If you have been diagnosed with glaucoma, you need to inform Service NSW (RTA) who may request a special visual field test (called an Estermann).
Informing the driving authorities does not mean you will be stopped from driving, but it is a requirement to let them know.