Glaucoma is a disease that damages the optic nerve. The optic nerve sends visual information from your eye to the brain. Damage due to glaucoma often occurs when fluid from the front portion of the eye compresses the optic nerve.
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 "glaucoma suspects" and have a higher risk of eventually developing glaucoma. They should be carefully monitored by an ophthalmologist.
Types of glaucoma
- Primary open-angle glaucoma
- Angle-closure glaucoma (also called “closed-angle glaucoma” or “narrow-angle 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.
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 or go to ER right away or you might go blind.
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.
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 glaucoma. This includes people who:
- over age 40
- have family members with glaucoma
- are of African, Hispanic, or Asian heritage
- high eye pressure
- are farsighted or nearsighted
- have had an eye injury
- use long-term steroid medications
- corneas that are thin in the center
- have thinning of the optic nerve
- with diabetes, migraines, high blood pressure, poor blood circulation or other health problems affecting the whole body
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, we 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
Modern medical (Eye drops) , laser (SLT or YAG laser procedure in the office depending on the type of glaucoma) or surgical intervention in the operating room is used to slow down or stop the progression of glaucoma.
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
- Your energy level is not the same
- irregular 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.
All medications can have 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 us 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 us 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 our office.
- Trabeculoplasty. This surgery is for people who have open-angle glaucoma. We use 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. We 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.
- Trabeculectomy: This is where the glaucoma surgeon creates a tiny flap in the sclera (white of your eye), and then 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. Glaucoma surgeon may implant a tiny drainage tube in your eye. It sends the fluid to a collection area (called a reservoir). This reservoir is usually placed 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.