What is 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 intraocullar pressure or IOP) stable. When the drainage angle is not working properly, fluid builds up. Pressure inside the eye rises, damaging the optic nerve.

If the drainage angle is blocked, fluid cannot flow out of the eye, causing pressure to increase
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.

How Do You Get Glaucoma?

There are two major types of glaucoma.

1- 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.

2- 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.

Open-angle glaucoma symptoms

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. Your ophthalmologist can tell you how often you should be examined.

Angle-closure glaucoma symptoms

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
• headache
• nausea
• vomiting

Normal tension glaucoma symptoms

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.

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

People with more than one of these risk factors have an even higher risk of glaucoma.

Medication

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.

Glaucoma medications can help you keep your vision, but they may also produce side effects. Some eye drops may cause:

• a stinging or itching sensation
• red eyes or red skin around the eyes
• changes in your pulse and heartbeat
• changes in your energy level
• changes in breathing (especially if you have asthma or breathing problems)
• dry mouth
• blurred vision
• eyelash growth
• changes in your eye color, the skin around your eyes or eyelid appearance

Laser surgery

There are two main types of laser surgery to treat glaucoma. They help aqueous drain from the eye.

Trabeculoplasty

This surgery is for people who have open-angle glaucoma and can be used instead of or in addition to medications. The eye surgeon uses a laser to make the drainage angle work better. That way fluid flows out properly and eye pressure is reduced.

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

Surgery

Some glaucoma surgery is done in an operating room. It creates a new drainage channel for the aqueous humor to leave the eye

Trabeculectomy

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This is where your eye surgeon creates a tiny flap in the sclera. They 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, lowering eye pressure. In the bleb, the fluid is absorbed by tissue around your eye.
In trabeculectomy, a flap is first created in the sclera (the white part of the eye). Then a small opening is made into the eye to release fluid from the eye.

Glaucoma drainage devices

Your ophthalmologist may implant a tiny drainage tube in your eye. The glaucoma drainage implant sends the fluid to a collection area (called a reservoir). Your eye surgeon creates this reservoir beneath the conjunctiva. The fluid is then absorbed into nearby blood vessels.

Cataract surgery

For some people with narrow angles, removing the eye’s natural lens  can lower eye pressure. With narrow angles, the iris and the cornea are too close together. This can cover (block) the eye’s drainage channel. Removing the eye’s lens with cataract surgery creates more space for fluid to leave the eye. This can lower eye pressure.