Glaucoma

Types of glaucoma

There are two major types of glaucoma:-

1.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.

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. 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.

3.Ocular Hypertension
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.

Symptoms of Glaucoma

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

2.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
• headache
• nausea
• vomiting

3.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.

4. Glaucoma suspects
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.

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.

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.

Risk factors for Glaucoma

Some people have a higher than normal risk of getting glaucoma. This includes people who:
1. are over age 40
2. have family members with glaucoma
3. are of African, Hispanic, or Asian heritage
4. have high eye pressure
5. are farsighted or nearsighted
6. have had an eye injury
7. use long-term steroid medications
8. have corneas that are thin in the center
9. have thinning of the optic nerve
10. have diabetes, migraine, high blood pressure, poor blood circulation or
11. 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 exam, 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

Treatment for Glaucoma

A. MEDICAL TREATMENT

Eyedrop medicines are helpful in treating glaucoma.

Glaucoma is a disease that affects your eye’s optic nerve, possibly leading to blindness. The optic nerve connects your eye to your brain so you can see. Glaucoma usually happens when fluid builds up in the front portion of your eye. Pressure increases in your eye, damaging the optic nerve and eventually stealing your sight.

Every dose, every day—it can save your sight!

It is extremely important to use your glaucoma eye drops exactly as your ophthalmologist tells you to. That includes taking every dose, every day. If you do not do this, you may lose vision.

Also, remember to tell your other doctors which medicines you take for glaucoma. As with any medication, glaucoma eye drops can cause side effects.Your ophthalmologist may have you take more than one of the following glaucoma eyedrop medicines.

1. Alpha agonists for glaucoma
Alpha agonists work by reducing the amount of fluid your eye produces. They also increase the amount of fluid that drains out of the eyes. This helps lower eye pressure.

Possible side effects of alpha agonists include:
• red, stinging or painful eyes after using drops
• blurry vision
• allergy (redness, itching, tearing and swelling of the eye)
• a large (dilated) pupil
• headaches
• dry mouth
• feeling tired, weak or dizzy
• an increase in blood pressure
• a fast or irregular heartbeat
• feeling nervous

Do not drive or operate machinery if your glaucoma eye drops make you feel tired or drowsy!

Blurry vision, stinging, and redness may improve with time. But if the side effects still bother you, call your ophthalmologist. He or she may be able to lower your dose or change your medicine. Most side effects go away when the medicine is stopped. Never suddenly quit taking your medicine unless your doctor tells you to.

2. Beta-blockers for glaucoma Beta-blockers work by reducing the amount of fluid your eye produces. This helps lower pressure in your eye.

Possible side effects of beta-blockers include:
• red, stinging or painful eyes after using drops
• blurry vision
• breathing problems in people with asthma, emphysema, or COPD
• a slow or irregular heartbeat
• feeling tired
• depression
• dizziness
• a change in sex drive or sexual function
• getting overly tired during exercise
• in people with diabetes, low blood sugar symptoms becoming difficult to notice

Blurry vision, stinging, and redness may improve with time. But if the side effects still bother you, call your ophthalmologist. He or she may be able to lower your dose or change your medicine. Most side effects go away when the medication is stopped. Never suddenly quit taking your medicine unless your doctor tells you to.

3. Carbonic anhydrase inhibitors for glaucoma
Carbonic anhydrase inhibitors work by reducing the amount of fluid your eye produces. This helps lower eye pressure.Your ophthalmologist may have you take this medicine as an eye drop or by mouth as a pill.

Possible side effects of carbonic anhydrase inhibitors include:
• stinging eyes
• red eyes
• blurry vision
• a skin rash (especially in people who are allergic to sulfa drugs)
• changes in how things taste to you (especially with carbonated drinks)
• bad taste or upset stomach (nausea)
• feeling tired
• decreased energy
• increase in urination (with the pills)
• tingling around the mouth and fingertips (with the pills)

Blurry vision, stinging, and redness may improve with time. But if the side effects still bother you, call your ophthalmologist. He or she may be able to lower your dose or change your medicine. Most side effects go away when the medication is stopped. Never suddenly quit taking your medicine unless your doctor tells you to.

4. Miotics for glaucoma Miotics make your pupil constrict (get smaller), increasing the amount of fluid that drains out of the eye. This helps lower eye pressure.

Possible side effects of miotics include:
• blurred vision
• nearsightedness (trouble focusing on distant objects)
• dim vision with difficulty seeing in the dark or at night
• headache or browache (aching around eye)

While very rare, there is the possibility that your retina could detach. This is when the light-sensitive tissue lining the back of the eye pulls away. You would suddenly notice dark specks or spots (floaters) or flashing lights in your vision. If you have these symptoms, call your ophthalmologist immediately.

Side effects may go away after you take the medicine for a while. But if the side effects still bother you, call your ophthalmologist. He or she may be able to lower your dose or change your medicine. Never suddenly quit taking your medicine unless your doctor tells you to.

5. Prostaglandin analogs for glaucoma Prostaglandin analogs work by increasing the drainage of fluid out of your eye. This helps lower eye pressure.

Possible side effects of prostaglandin analogs include:
• red, stinging or painful eyes after using drops
• feeling like something is in your eye
• blurry vision
• a permanent change in your eye color (occurs mostly in hazel eyes)
• an increase in thickness, number and length of eyelashes
• darkening of the eyelid
• upper respiratory tract infections, such as colds and flu
• joint aches
• light sensitivity
• eyes gradually sinking deeper into their sockets, keeping eyelids from working properly

Blurry vision, stinging, and redness may improve with time. But if the side effects still bother you, call your ophthalmologist. He or she may be able to lower your dose or change your medicine. Most side effects go away when the medication is stopped. Never suddenly quit taking your medicine unless your doctor tells you to.

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.

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.

B. LASER SURGERY

“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.”

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.

1. 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.
2. 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.

C. SURGICAL PROCEDURE

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

1. 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 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.
2. 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.

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.

Glaucoma Vision Simulator

How does glaucoma affect your vision?

The optic nerve is made up of many nerve fibers that carry images to the brain. It’s like an electric cable containing numerous wires. When glaucoma damages the optic nerve fibers, blind spots develop. If the entire nerve is destroyed, blindness results.

As the optic nerve becomes more damaged, blank spots begin to appear in your field of vision. You typically won’t notice these blank spots in your day-to-day activities until the optic nerve is significantly damaged and these spots become large.