What is it?
Glaucoma is the clinical condition in which the nerve at the back of the eye (optic nerve) is damaged and the eyesight characteristically affected, with increased pressure in the eyeball being an important risk factor.
The eyeballs contain a transparent fluid called aqueous humour. This
fluid constantly flows in and out of theeyeballs bringing nutrients to the eye. But if the fluid doesn’t leave the eye as easily as it enters, pressure can build up inside the eye. This pressure can press on the nerve at the back of your eye and damage it over time.
It’s however also possible to get glaucoma even when the pressure in the eyes is normal. This may happen if the optic nerves are very sensitive to pressure.
The open-angle glaucoma, which is only one type of glaucoma, is the most common. It tends to happen gradually as opposed to the angle-closure glaucoma which comes on more suddenly.
What are the symptoms?
Open-angle glaucoma is characteristically painless and can occur in one or both eyes. The first symptoms are small blind spots at the edge of your vision. Gradually, these spots get bigger until you can only see things directly in front of you. This happens so slowly that many people don’t notice it at first.
In severe glaucoma, one may find it hard to see if they move from a bright place to a darker one. They may also trip and fall easily as they find it difficult to judge the height of steps and elevations.
What treatments work?
Management usually aims at reducing the pressure in the eye. The use of eye drops, laser treatment and surgery are available treatment options depending on the severity of damage and co-existing health conditions which may discourage the use of any of the treatments.
Eye drops for glaucoma can reduce the pressure inside the eyes and stop the ongoing damage. A number of different types of such eye drops exist, including those containing drugs called beta blockers, and others containing drugs called prostaglandin analogues. Eye drops can cause burning or stinging sensation in the eyes. Beta-blockers can cause low blood pressure or a slow heartbeat. An effective manoeuvre that can be done to reduce these side effects is pressing down on the tear duct (at the corner of each eye close to the nose) for a few minutes after applying the drops. This reduces the amount of drug entering the bloodstream.
Laser treatment may be used when eye drops don’t work well enough. The laser goes through a special artificial lens placed against the eye to the tissue that drains the aqueous humour. This allows the fluid drain away better.
If the above treatments don’t work, or if vision is rapidly deteriorating, surgery may be the only option. The operation is called a trabeculectomy. It doesn’t take more than a couple of hours, and you are likely to go home the same day it is done.
Surgery however increases the risk of cataracts, which may in turn require another surgery.
How can I prevent it?
Regular eye tests are recommended for everyone. However, some people are more at risk of getting glaucoma, and hence are in greater need of these eye tests. They include:
• people with a first-degree relative with glaucoma
• people of African-Caribbean origin, and
• people with eye problems caused by diabetes.