What is Glaucoma?

Glaucoma is a potentially blinding eye condition that manifests in different ways. Because the signs, symptoms, and treatment of the different types of glaucoma are so varied, one person with glaucoma may have sudden pain and redness, while another may have no symptoms at all. In general, glaucoma is an eye condition that develops when too much pressure builds up inside of the eye. It tends to be inherited and may not show up until later in life. The increased pressure, called intraocular pressure (IOP), can damage the optic nerve, which transmits images to the brain. If damage to the optic nerve from high IOP continues, glaucoma will cause loss of vision. Without treatment, glaucoma can cause total, permanent blindness within a few years.

There are two main types of glaucoma - open-angle glaucoma and angle-closure glaucoma. Open-angle glaucoma is also referred to as wide-angle glaucoma and is the most common type of glaucoma. The structures of the eye appear normal, but fluid in the eye does not flow properly through the eye's filter, called the trabecular meshwork.

Angle-closure glaucoma, also called acute or chronic angle-closure or narrow-angle glaucoma, is less common than open-angle glaucoma, but can cause a sudden build-up of pressure in the eye. Drainage may be poor because the angle between the iris and the cornea (where a drainage channel for the eye is located) is too narrow. Or, the pupil opens too wide, narrowing the angle and blocking the flow of the fluid through that channel.

Globally glaucoma is the second leading cause of blindness, affecting 6.7 million people in 2000. 66.8 million people worldwide have glaucoma, and most are not even aware of it. That number is predicted to grow past 80 million by 2020. Global causes of blindness as a percentage of total blindness (WHO Report 2002).