What is Glaucoma?
Conditions > What is Glaucoma?
Glaucoma can steal your sight without any warning. This group of eye diseases causes vision loss due to damage to the optic nerve.
High intraocular pressure (IOP) was once believed to be the main cause of this optic nerve damage. IOP is a risk factor, but other factors can be involved too. There are two main types of glaucoma: open angle glaucoma and angle closure glaucoma.
Primary open angle glaucoma is the most common form. This form of glaucoma occurs when the eye’s drainage canals get clogged. The inner eye pressure rises because fluid isn’t draining properly from the eye. The clogging problem is inside the drainage canals.
There usually is no warning for this type of glaucoma. If open angle glaucoma isn’t diagnosed and treated, vision will gradually be lost. The best way to make sure you are screened for glaucoma is to visit an optometrist or ophthalmologist on a regular basis. It can be treated with medication if caught early.
Angle closure glaucoma is also known as acute glaucoma or narrow angle glaucoma. It is fairly rare and it is different than open angle glaucoma because eye pressure usually goes up very quickly. This happens when the drainage canals get blocked or covered. With angle closure glaucoma, the iris and cornea is too narrow. The outer edge of the iris bunches up over the drainage canals, when the pupil gets too big too fast.
The second type of glaucoma generally requires surgery to remove a small piece of the outer edge of the iris so the drainage canals can be unblocked and fluid allowed to drain.
There are other types of glaucoma with different causes including eye secondary glaucoma caused by eye injury, inflammation, tumor or advanced cases of cataracts or diabetes. Certain drugs, such as steroids, can also cause this disease.
Normal tension glaucoma is also known as low tension glaucoma or normal pressure glaucoma. In this situation the optic nerve is damaged even though intraocular pressure (IOP) is not very high. Doctors do not know why some people’s optic nerves are damaged even though they have what is considered to be normal pressure levels.
Some people are at higher risk for normal tension glaucoma including those:
- with a family history of normal tension glaucoma
- Of Japanese ancestry
- with a history of systemic heart disease, such as irregular heart rhythm
Normal tension glaucoma is usually detected after an examination of the optic nerve.