Glaucoma is a disease that damages your eye’s optic nerve. It usually 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. But blindness from glaucoma can often be prevented with early treatment.
There are two major types of glaucoma.
I. Primary open-angle glaucoma
This is the most common type. 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.
II. 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
- Have a headache
- You feel sick to your stomach (nausea)
- 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.
I. Open-angle glaucoma
With open-angle glaucoma, there are no warning signs or obvious symptoms in the early stages. As the disease progresses, blind spots develop in your peripheral (side) vision.
Most people with open-angle glaucoma do not notice any change in their vision until the damage is quite severe. This is why glaucoma is called the “silent thief of sight.” Having regular eye exams can help your ophthalmologist find this disease before you lose vision.
II. Angle-closure glaucoma
People at risk for angle-closure glaucoma usually show no symptoms before an attack. Some early symptoms of an attack may include blurred vision, halos, mild headaches or eye pain. People with these symptoms should be checked by their ophthalmologist as soon as possible. An attack of angle-closure glaucoma includes the following:
- severe pain in the eye or forehead
- redness of the eye
- decreased vision or blurred vision
- seeing rainbows or halos
III. Normal tension glaucoma
People with “normal tension glaucoma” have eye pressure that is within normal ranges, but show signs of glaucoma, such as blind spots in their field of vision and optic nerve damage.
Some people have no signs of damage but have higher than normal eye pressure (called ocular hypertension). These patients are considered “suspects” and have a higher risk of eventually developing the disease. They should be carefully monitored by an ophthalmologist.
Your eye constantly makes a fluid called aqueous humor. As new fluid 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 not working properly, fluid builds up. Consequently, pressure inside the eye rises and damages 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.
Some people have a higher than normal risk of getting this disease. 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
- display corneas that are thin in the center
- have thinning of the optic nerve
- suffer from diabetes, migraines, poor blood circulation or other health problems affecting the whole body
- inspect your eye’s drainage angle
- examine your optic nerve for damage
- measure your eye pressure
- test your peripheral (side) vision
- take a picture or computer measurement of your optic nerve
- measure the thickness of your cornea
Glaucoma is usually controlled with eyedrop medicine. Used every day, these eye drops lower eye pressure. Some do this by reducing the amount of aqueous fluid the eye makes. Others reduce pressure by helping fluid flow better through the drainage angle.
There are two main types of laser surgery to treat glaucoma. They help aqueous drain from the eye. These procedures are usually done in the ophthalmologist’s office or an outpatient surgery center.
Trabeculoplasty. This surgery is for people who have open-angle glaucoma. The eye surgeon uses a laser to make the drainage angle work better. That way fluid flows out properly and eye pressure is reduced.
Iridotomy. This is for people who have angle-closure glaucoma. The ophthalmologist uses a laser to create a tiny hole in the iris. This hole helps fluid flow to the drainage angle.
Trabeculectomy. This is where the eye surgeon creates a tiny flap in the sclera (white of your eye). The surgeon will also create a bubble (like a pocket) in the conjunctiva called a filtration bleb. It is usually hidden under the upper eyelid and cannot be seen. Aqueous humor will be able to drain out of the eye through the flap and into the bleb. In the bleb, the fluid is absorbed by tissue around your eye, lowering eye pressure.
Glaucoma drainage devices. The ophthalmologist may implant a tiny drainage tube in the eye. It sends the fluid to a collection area (called a reservoir).The eye surgeon creates this reservoir beneath the conjunctiva (the thin membrane that covers the inside of your eyelids and white part of your eye). The fluid is then absorbed into nearby blood.