There are two major types of glaucoma.

Primary open-angle glaucoma

This is the most common type of glaucoma. It happens gradually, where the eye does not drain fluid as well as it should (like a clogged drain). As a result, eye pressure builds and starts to damage the optic nerve. This type of glaucoma is painless and causes no vision changes at first.

Some people can have optic nerves that are sensitive to normal eye pressure. This means their risk of getting glaucoma is higher than normal. Regular eye exams are important to find early signs of damage to their optic nerve.

Angle-closure glaucoma (also called “closed-angle glaucoma” or “narrow-angle glaucoma”)

This type happens when someone’s iris is very close to the drainage angle in their eye. The iris can end up blocking the drainage angle. You can think of it like a piece of paper sliding over a sink drain. When the drainage angle gets completely blocked, eye pressure rises very quickly. This is called an acute attack. It is a true eye emergency, and you should call your ophthalmologist right away or you might go blind.

Here are the signs of an acute angle-closure glaucoma attack:

Your vision is suddenly blurry
You have severe eye pain
You have a headache
You feel sick to your stomach (nausea)
You throw up (vomit)
You see rainbow-colored rings or halos around lights

Many people with angle-closure glaucoma develop it slowly. This is called chronic angle-closure glaucoma. There are no symptoms at first, so they don’t know they have it until the damage is severe or they have an attack.

Angle-closure glaucoma can cause blindness if not treated right away

Who is at risk for Glaucoma?

Some people have a higher than normal risk of getting glaucoma. This includes people who:

are over age 40
have family members with glaucoma
are of African, Hispanic, or Asian heritage
have high eye pressure
are farsighted or nearsighted
have had an eye injury
use long-term steroid medications
have corneas that are thin in the center
have thinning of the optic nerve
have diabetes, migraines, high blood pressure, poor blood circulation or other health problems affecting the whole body

Talk with an ophthalmologist about your risk for getting glaucoma. People with more than one of these risk factors have an even higher risk of glaucoma.