What Is Glaucoma?
Glaucoma is a disease that damages your optic nerve . It happens when fluid builds up in the front part of your eye. That extra fluid increases the pressure in your eye, damaging the optic nerve. Glaucoma is a leading cause of blindness for people over 60 years old and is the number one cause of blindness in African American males. The good news is blindness from glaucoma can often be prevented with early treatment.
Types of glaucoma
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.
What Are the Symptoms of Glaucoma?
Glaucoma has no symptoms in its early stages. In fact, half the people with glaucoma do not know they have it! Having regular eye exams can help your ophthalmologist find this disease before you lose vision. Your ophthalmologist can tell you how often you should be examined.
Causes of Glaucoma
Your eye constantly makes aqueous humor . As new aqueous flows into your eye, the same amount should drain out. The fluid drains out through an area called the drainage angle . This process keeps pressure in the eye (called intraocular pressure or IOP) stable. But if the drainage angle is notworking properly, fluid builds up. Pressure inside the eye rises, damaging the optic nerve.
The optic nerve is made of more than a million tiny nerve fibers. It is like an electric cable made up of many small wires. As these nerve fibers die, you will develop blind spots in your vision. You may not notice these blind spots until most of your optic nerve fibers have died. If all of the fibers die, you will become blind.
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 or Hispanic heritage
- have high eye pressure
- are farsighted or nearsighted
- have had an eye injury
- have corneas that are thin in the center
- have thinning of the optic nerve
- have diabetes , migraines , 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.
The only sure way to diagnose glaucoma is with a complete eye exam. A glaucoma screening that only checks eye pressure is not enough to find glaucoma.
During a glaucoma exam, your ophthalmologist will:
- measure your eye pressure
- inspect your eye’s drainage angle
- examine your optic nerve for damage
- test your peripheral (side) vision
- take a picture or computer measurement of your optic nerve
- measure the thickness of your cornea