GLAUCOMA

What Is Glaucoma?

Glaucoma is a disease condition which affects the eyes, especially optic nerve and in most cases is associated with elevated intraocular pressure. Optic nerve is the main nerve of eye, which transmits images from retina of eye to brain, which help us to see those images. Intraocular pressure is the pressure within the eye caused by a nourishing liquid of eye called aqueous humour. This liquid is produced and drained by the eyes. But Glaucoma can also happen if this pressure is normal.

Glaucoma can damage the Optic nerve and can cause peripheral vision loss which may progress to irreversible blindness, if not treated timely.
 
Most people with Glaucoma are not even aware of the disease, since in most cases it is asymptomatic in the beginning. Hence it is important to check eyes routinely especially after 40 years of age.






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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 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.










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What Are the Symptoms of Glaucoma?

Glaucoma is a silent thief of sight

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 humour. 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 fibres. It is like an electric cable made up of many small wires. As these nerve fibres die, you will develop blind spots in your vision. You may not notice these blind spots until most of your optic nerve fibres have died. If all of the fibres 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 centre
• 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.
 
Glaucoma Diagnosis

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 examination, 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

Glaucoma Treatment

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.
Medications
Glaucoma is usually controlled with eye drop medicine. Used every day, these eyes 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.
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 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.

Laser surgery
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 centre.
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.
Operating room surgery
Some glaucoma surgery is done in an operating room. It creates a new drainage channel for the aqueous humour to leave the eye.
Trabeculectomy. 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 humour 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.

Your role in glaucoma treatment
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Treating glaucoma successfully is a team effort between you and your doctor. Your ophthalmologist will prescribe your glaucoma treatment. It is up to you to follow your doctor’s instructions and use your eye drops.
Once you are taking medications for glaucoma, your ophthalmologist will want to see you regularly. You can expect to visit your ophthalmologist about every 3–6 months. However, this can vary depending on your treatment needs.
If you have any questions about your eyes or your treatment, talk to your ophthalmologist.

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