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.
Types of Glaucoma
Primary open-angle glaucoma 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”) is when the 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.
Causes of Glaucoma
If the drainage angle is blocked, excess fluid cannot flow out of the eye, causing the fluid pressure to increase. 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 not working properly, fluid builds up. Pressure inside the eye rises, damaging the optic nerve.
Glaucoma damage is permanent—it cannot be reversed. But medicine and surgery help to stop further damage.
To treat glaucoma, your ophthalmologist may use one or more of the following treatments.
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 drugs can cause problems when taken with other medications. It is important to give your doctor a list of every medicine you take regularly. Be sure to talk with your ophthalmologist if you think you may have side effects from glaucoma medicine.
Never change or stop taking your glaucoma medications without talking to your ophthalmologist. If you are about to run out of your medication, ask your ophthalmologist if you should have your prescription refilled.
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.
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.
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.
Operating room surgery
Some glaucoma surgery is done in an operating room. It creates a new drainage channel for the aqueous humor to leave the eye.
This is where your eye surgeon creates a tiny flap in the sclera (white of your eye). He or she 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
Your ophthalmologist may implant a tiny drainage tube in your eye. It sends the fluid to a collection area (called a reservoir). Your 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 vessels.
The information contained here was adapted from EyeSmart – The American Academy of Ophthalmology