Glaucoma is an eye disease that is often associated with elevated intraocular pressure, in which damage to the eye (optic) nerve can lead to loss of vision and even blindness.
Glaucoma is the leading cause of irreversible blindness in the world.
What is Glaucoma?
Glaucoma is a disease of the major nerve of vision, called the optic nerve. The optic nerve receives light-generated nerve impulses from the retina and transmits these to the brain, where we recognize those electrical signals as vision. Glaucoma is characterized by a particular pattern of progressive damage to the optic nerve that generally begins with a subtle loss of side vision (peripheral vision). If glaucoma is not diagnosed and treated, it can progress to loss of central vision and blindness.
Glaucoma is usually, but not always, associated with elevated pressure in the eye (intraocular pressure). Generally, it is this elevated eye pressure that leads to damage of the eye (optic) nerve. In some cases, glaucoma may occur in the presence of normal eye pressure. This form of glaucoma is believed to be caused by poor regulation of blood flow to the optic nerve.
Causes
Elevated pressure in the eye is the main factor leading to glaucomatous damage to the eye (optic) nerve. Glaucoma with normal intraocular pressure is discussed below in the section on the different types of glaucoma. The optic nerve, which is located in the back of the eye, is the main visual nerve for the eye. This nerve transmits the images we see back to the brain for interpretation. The eye is firm and round, like a basketball. Its tone and shape are maintained by a pressure within the eye (the intraocular pressure), which normally ranges between 8 millimeters (mm) and 22 mm of mercury. When the pressure is too low, the eye becomes softer, while elevated pressure causes the eye to become harder. The optic nerve is the most susceptible part of the eye to high pressure because the delicate fibers in this nerve are easily damaged either by direct pressure on the nerve or decreased blood flow to the nerve.
Risk Factors
It mostly affects adults over 40, but young adults, children, and even infants can have it. African American people tend to get it more often, when they're younger, and with more vision loss.
You’re more likely to get it if you:
• Are of African American, Irish, Russian, Japanese, Hispanic, Inuit, or Scandinavian descent
• Are over 40
• Have a family history of glaucoma
• Are nearsighted or farsighted
• Have poor vision
• Have diabetes
• Take certain steroid medications such as prednisone
• Take certain drugs for bladder control or seizures, or some over-the-counter cold remedies
• Have had an injury to your eye or
• Have corneas that are thinner than usual
• Have high blood pressure, heart disease, diabetes, or sickle cell anemia
• Have high eye pressure
Types of Glaucoma
Five major types of glaucoma exist. These are:
1. Open-Angle (Chronic) Glaucoma
Open-angle, or chronic, glaucoma has no signs or symptoms except gradual vision loss. This loss may be so slow that your vision can suffer irreparable damage before any other signs become apparent and this is the most common type of glaucoma.
2. Angle-Closure (Acute) Glaucoma
If the flow of your aqueous humor fluid is suddenly blocked, the rapid buildup of fluid may cause a severe, quick, and painful increase in pressure. Angle-closure glaucoma is an emergency situation. You should call your doctor immediately if you begin experiencing symptoms, such as severe pain, nausea, and blurred vision.
3. Congenital Glaucoma
Children born with congenital glaucoma have a defect in the angle of their eye, which slows or prevents normal fluid drainage. Congenital glaucoma usually presents with symptoms, such as cloudy eyes, excessive tearing, or sensitivity to light. Congenital glaucoma can run in families.
4. Secondary Glaucoma
Secondary glaucoma is often a side effect of injury or another eye condition, such as cataracts or eye tumors. Medicines, such as corticosteroids, may also cause this type of glaucoma. Rarely, eye surgery can cause secondary glaucoma.
5. Normal Tension Glaucoma
In some cases, people without increased eye pressure develop damage to their optic nerve. The cause of this isn’t known. However, extreme sensitivity or a lack of blood flow to your optic nerve may be a factor in this type of glaucoma.
Symptoms
The most common type of glaucoma is primary open-angle glaucoma. It has no signs or symptoms except gradual vision loss. For that reason, it’s important that you go to yearly comprehensive eye exams so your ophthalmologist, or eye specialist, can monitor any changes in your vision.
Acute-angle closure glaucoma, which is also known as narrow-angle glaucoma, is a medical emergency. See your doctor immediately if you experience any of the following symptoms:
• severe eye pain
• nausea
• vomiting
• redness in your eye
• sudden vision disturbances
• seeing colored rings around lights
• sudden blurred vision
Diagnosis
To diagnose glaucoma, your ophthalmologist will want to perform a comprehensive eye examination. They’ll check for signs of deterioration, including loss of nerve tissue. They may also use one or more of the following tests and procedures:
1. Detailed Medical History
Your doctor will want to know what symptoms you’ve been experiencing and if you have any personal or family history of glaucoma. They’ll also ask for a general health assessment to determine if any other health conditions may be impacting your eye health, such as diabetes or high blood pressure.
2. Tonometry Test
This class of tests measures your eye’s internal pressure.
3. Pachymetry Test
People with thin corneas have an increased risk of developing glaucoma. A pachymetry test can tell your doctor if your corneas are thinner than average.
4. Perimetry Test
This test, also known as a visual field test, can tell your doctor if glaucoma is affecting your vision by measuring your peripheral, or side, vision and your central vision.
5. Monitoring Your Optic Nerve
If your doctor wants to monitor for gradual changes to your optic nerve, they may take photographs of your optic nerve to conduct a side-by-side comparison over time.
Treatment
The goal of glaucoma treatment is to reduce IOP to stop any additional eyesight loss. Typically, your doctor will begin treatment with prescription eye drops. If these don’t work or more advanced treatment is needed, your doctor may suggest one of the following treatments:
1. Medications
Several medicines designed to reduce intraocular pressure (IOP) are available. These medicines are available in the form of eye drops or pills, but the drops are more common. Your doctor may prescribe one or a combination of these.
2. Surgery
If a blocked or slow channel is causing increased intraocular pressure (IOP), your doctor may suggest surgery to make a drainage path for fluid or destroy tissues that are responsible for the increased fluid.
Treatment for angle-closure glaucoma is different. This type of glaucoma is a medical emergency and requires immediate treatment to reduce eye pressure as quickly as possible. Medicines are usually attempted first, to reverse the angle closure, but this may be unsuccessful. A laser procedure called laser peripheral iridotomy may also be performed. This procedure creates small holes in your iris to allow for increased fluid movement.
Prevention
You can’t prevent glaucoma. But if you find it early, you can lower your risk of eye damage. These steps may help protect your vision:
1. Have regular eye exams :- The sooner your doctor spots the signs of glaucoma, the sooner you can start treatment. All adults need to be checked for glaucoma every 3 to 5 years. If you’re over age 40 and have a family history of the disease, get a complete eye exam from an eye doctor every 1 to 2 years. If you have health problems like diabetes or are at risk of other eye diseases, you may need to go more often.
2. Learn your family history :- Ask your relatives whether any of them have been diagnosed with glaucoma.
3. Follow your doctor’s instructions :- If they find that you have high eye pressure, they might give you drops to prevent glaucoma.
4. Exercise :- Do moderate activity like walking or jogging at least three times a week.
5. Protect your eyes :- Use protective eyewear when playing sports or working on home improvement projects.
Tips for Living With Glaucoma
Glaucoma is a lifelong condition and needs continual follow-up with your eye doctor. There are other things you can do to help keep your eyes healthy.
1. Get moving - Regular exercise may help lower eye pressure and keep blood flowing to the nerves in your eye. Some activities can raise pressure, so talk to your doctor about the best exercise program for you.
2. Eat healthy - Enjoy a healthy, well-rounded diet. It won't keep your glaucoma from getting worse, but it's key to keeping your body and eyes healthy. Some studies suggest that food high in antioxidants can help when you have glaucoma. Eat more nutrient-rich foods like:
• Dark, leafy greens
• Fish that's packed with omega-3 fatty acids
3. Take your medicine - Be sure to take your drops or pills exactly as directed. Set a reminder on your phone or watch so you don't forget. Missing your meds could make your glaucoma worse.
4. Careful with contacts - You should be able to continue wearing contact lenses if you use medicated eye drops. But you may need to use some drugs when you don’t have lenses in. Also, some older medications can change your vision prescription. And if you need surgery, it may affect your ability to wear contacts.
5. Don't smoke - It's important to keep your body healthy, and nicotine takes a toll. Smoking also raises blood pressure and eye inflammation. That can make your risk of diabetes and cataracts go up. Both are risk factors for glaucoma. If you smoke, ask your doctor for advice on how to quit.
6. Watch your caffeine - Watch how much soda, coffee, and tea you drink. Too much caffeine can raise your eye pressure. One study found that just a cup of coffee could make the pressure in your eye go up a significant amount for up to 90 minutes.
7. Elevate your head - Use a wedge pillow when you sleep. It'll keep your head raised just a little. That should help lower your eye pressure.
8. Drink fluids slowly - Don't cut back on how much you drink, but spread out your beverages through the day. If you drink a lot at once, it can strain your eyes. Don't have more than a quart at one time. Instead, sip small amounts.
9. Protect your eyes - Put on protective glasses when you work in the yard or play contact sports. Wear goggles when you swim. When choosing makeup, use non-allergenic brands, and replace items often. Be sure to wear sunglasses outside, especially in summer or around high-glare surfaces like sand, snow, and water. When you have glaucoma, your eyes can be very sensitive to glare.
10. Don't rub - Glaucoma and the medicine you take might make your eyes feel itchy. But fight the urge. You can scratch them and make things worse. Ask your doctor if you can use drops to treat dryness.
11. Drive safely - Most people with glaucoma can still drive as long as they pass their state’s vision test. Simply put, your ability to drive will depend on how much vision has been lost. Some people with advanced glaucoma can get their license renewed with restrictions. Ask your doctor about whether driving will be a concern for you.
12. Be careful with yoga - You may need to reconsider some yoga positions. Some head-down moves that put your heart above your eye can raise your eye pressure. Research hasn’t shown that it makes glaucoma worse, but it’s not a good idea to do yoga positions that increase eye pressure. You may want to avoid poses such as:
• Downward-facing dog
• Standing forward bend
• Plow
• Legs up the wall
Conclusion
• Glaucoma is an eye disease that is often associated with elevated intraocular pressure, in which damage to the eye (optic) nerve can lead to loss of vision and even blindness.
• Glaucoma is the leading cause of irreversible blindness in the world.
• Glaucoma usually causes no symptoms early in its course, at which time it can only be diagnosed by regular eye examinations (screenings with the frequency of examination based on age and the presence of other risk factors).
• Intraocular pressure increases when either too much fluid is produced in the eye or the drainage or outflow channels (trabecular meshwork) of the eye become blocked.
• While anyone can develop glaucoma, some people are at greater risk.
• Damage to the optic nerve and impairment of vision from glaucoma is irreversible.
• Early diagnosis and treatment are key to preserving sight in people with glaucoma.
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