Glaucoma
Glaucoma is a disease that damages the optic nerve and causes vision loss. The tricky part of glaucoma is that it is sneaky and most patients don’t know they have it. Hence, regular eye exams are needed to detect this “silent” disease. Damage to the optic nerve can occur when the intraocular pressure of the eye increases. The elevated eye pressure almost always goes unnoticed by the patient, because there is no pain until the eye pressure is very, very high. Unlike blood pressure, patients can’t check their eye pressure at home. An elevated eye pressure usually occurs due to a build-up of aqueous fluid inside the eye because of a problem with the internal drainage canal (outflow of excess fluid from inside the eye). The elevation of pressure may lead to damage to the optic nerve, and then to the development of blind spots in the field of vision. Blind spots in the field of vision usually go undetected by the individual until the optic nerve is significantly damaged.
Glaucoma is actually not one disease, but rather there are several types of glaucoma. The most common is called primary open angle glaucoma (POAG), also called chronic open angle glaucoma (COAG) or just open angle glaucoma. These patients need regular measurement of their eye pressure, regular visual field tests, and regular evaluation of their optic nerves with photographs and OCT scans. POAG patients can be treated with medicated eye drops, laser and surgery to lower the eye pressure.
Vision loss may even occur without elevation of the intra-ocular pressure in some patients with glaucoma. This type of open angle glaucoma goes by many names including low tension glaucoma, low pressure glaucoma, normal tension glaucoma, or normal pressure glaucoma. Medicated eye drops, laser, and surgery are used for low tension glaucoma.
Another type of glaucoma is acute angle closure glaucoma. In this type of glaucoma the drainage angle becomes blocked by otherwise normal tissue inside the eye. This prevents any fluid from draining from the eye and causes the pressure within the eye to suddenly rise. This can lead to an extreme rise in pressure causing issues such as blurred vision, headaches, severe eye pain and the appearance of halos around lights. There are less sudden types of angle closure glaucoma such as chronic angle closure glaucoma, intermittent angle closure glaucoma, and narrow angle glaucoma. These glaucomas are usually treated with laser first, then eye drops and other surgeries.
Finally, there are numerous other types of glaucoma including exfoliation glaucoma (also called pseudoexfoliation glaucoma), neovascular glaucoma, pigmentary glaucoma, traumatic glaucoma, steroid induced glaucoma, uveitic glaucoma, and others.