What is glaucoma and how do you get it?

02 December 2007



I’ve got a friend who was diagnosed with glaucoma by the optician. What is it and how do you get it?


The answer to this is it's not something you can catch, fortunately. Glaucoma seems to run in families. It's caused by a raised pressure inside the eye. At the front of the eye you produce fluid and this fluid fills the front of the eye and it then gets reabsorbed further back in the eye. The fluid's continuously being replenished. Sometimes in people with glaucoma, they don't reabsorb the fluid properly and so the pressure can go up. This puts pressure on the retina, the part of the eye that converts light into nerve signals that the brain can understand. Over time this can damage the retina. In particular, it damages the part of the eye called the optic nerve.

All of the information that the retina sends to the brain, it does so along the optic nerve. There's about a million nerve fibres in the optic nerve on each side. They run through this structure called the optic disc at the back of the eyeball. You can see this in people's eyes who have raised pressure; you can see the changes that are very characteristic in this optic disc. If you reduce the pressure with drug then what this does is reduce the severity of those changes. If you catch it early and take drugs you can prevent any damage from happening. Depending upon when you catch it then there can be more or less damage to the eye.

The optic nerve is part of your central nervous system and if you damage the central nervous system then it doesn't grow back. If you lose a connection or some of the nerve fibres from your retina to your brain then you do lose acuity: the ability to see as sharply as you once did. The longer a problem goes on, the worse it can be. If you have a family history of glaucoma then it's worth going and seeing an optician just to get checked out.


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