Glaucoma occurs when the optic nerve, which connects your eye to your brain, is damaged by the pressure of the fluid inside your eye.
This may be because the pressure is higher than normal, or because the nerve is more susceptible to damage from pressure. This may affect one or both of your eyes.
Because you cannot feel the pressure, and the damage happens slowly, you may not know you have glaucoma until a lot of damage has been done. That damage cannot be put right, so it is particularly important that you find out early. The best way to make sure of this is to have a regular eye examination with an optometrist. If you are at risk of developing glaucoma, you should have an eye examination at least every two years, or more often if your optometrist recommends it.
If you have glaucoma but do not treat it, your eyesight will gradually get worse, and you could eventually go blind. The good news is that treatment with eye drops may stop it getting worse.
Read more about Glaucoma, here