What Are the Different Types of Glaucoma?
Glaucoma is a group of eye diseases that can lead to blindness by damaging the optic nerve. The eye continuously produces a fluid, called the aqueous, that must drain from the eye to maintain healthy eye pressure.
Primary Open Angle Glaucoma
The most common type of glaucoma is Primary Open Angle Glaucoma (POAG). In POAG, the eye’s drainage canals become blocked, and the fluid accumulation causes pressure to build within the eye. This pressure can cause damage to the optic nerve, which transmits information from the eye to the brain.
Vision loss is usually slow and gradual and often there are no early warning signs. There is a strong genetic predisposition for this type of glaucoma.
Angle Closure Glaucoma
Angle Closure Glaucoma is much less common than POAG in the United States. In this type of glaucoma, the aqueous cannot drain properly because the entrance to the drainage canal is either too narrow or is closed completely. In this case, eye pressure can rise very quickly and can be triggered by pupil dilation.
Symptoms can include sudden eye pain, nausea, headaches, and blurred vision. If you experience these symptoms, you should seek immediate medical treatment.
Normal Tension Glaucoma
In this type of glaucoma, also called low-pressure glaucoma, the optic nerve is damaged even though the eye pressure is not excessively elevated. A family history of any type of glaucoma, cardiovascular disease, and Japanese ancestry are a few of the risk factors for this type of glaucoma.
This type of glaucoma is treated much like POAG, but the eye pressure needs to be kept even lower to prevent progression of vision loss.
Secondary glaucomas are those that develop as secondary to, or as complications of, other conditions such as eye trauma, cataracts, diabetes, eye surgery, or tumors. In many of these glaucomas, damage to the fluid drainage canal must be addressed with medication or surgery.
As in the other types of glaucoma, the sooner eye pressure is normalized, the more functional vision can be preserved.
For more detailed and patient-centered information about glaucoma detection, treatment, and everyday management, see VisionAware’s new Patient’s Guide to Living with Glaucoma and Guía del Paciente: Vivir con Glaucoma.
The typical progression of vision loss from glaucoma
Source: National Eye Institute