Glaucoma is a group of eye conditions that damage the optic nerve, the health of which is vital for good vision. This damage is often caused by an abnormally high pressure in your eye. Glaucoma is one of the leading causes of blindness for people over the age of 60. It can occur at any age but is more common in older adults. Many forms of glaucoma have no warning signs. The effect is so gradual that you may not notice a change in vision until the condition is at an advanced stage.
Because vision loss due to glaucoma can't be recovered, it's important to have regular eye exams that include measurements of your eye pressure so a diagnosis can be made in its early stages and treated appropriately. If glaucoma is recognized early, vision loss can be slowed or prevented. If you have the condition, you'll generally need treatment for the rest of your life.
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.
· Patchy blind spots in your side (peripheral) or central vision, frequently in both eyes
· Tunnel vision in the advanced stages
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.
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.
In normal-tension glaucoma, your optic nerve becomes damaged even though your eye pressure is within the normal range. No one knows the exact reason for this. You may have a sensitive optic nerve, or you may have less blood being supplied to your optic nerve. This limited blood flow could be caused by atherosclerosis — the buildup of fatty deposits (plaque) in the arteries — or other conditions that impair circulation.
This is a rarer form of glaucoma that experts do not fully understand. Even though eye pressure is normal, optic nerve damage still occurs. It might be due to reduced blood supply to the optic nerve.
It's possible for infants and children to have glaucoma. It may be present from birth or develop in the first few years of life. The optic nerve damage may be caused by drainage blockages or an underlying medical condition.
In pigmentary glaucoma, pigment granules from your iris build up in the drainage channels, slowing or blocking fluid exiting your eye. Activities such as jogging sometimes stir up the pigment granules, depositing them on the trabecular meshwork and causing intermittent pressure elevations.
Glaucoma is the result of damage to the optic nerve. As this nerve gradually deteriorates, blind spots develop in your visual field. For reasons that doctors don't fully understand, this nerve damage is usually related to increased pressure in the eye.
Elevated eye pressure is due to a buildup of a fluid (aqueous humor) that flows throughout the inside of your eye. This internal fluid normally drains out through a tissue called the trabecular meshwork at the angle where the iris and cornea meet. When fluid is overproduced or the drainage system doesn't work properly, the fluid can't flow out at its normal rate and eye pressure increases.
Glaucoma tends to run in families. In some people, scientists have identified genes related to high eye pressure and optic nerve damage.
Because chronic forms of glaucoma can destroy vision before any signs or symptoms are apparent, be aware of these risk factors:
· Having high internal eye pressure (intraocular pressure)
· Being over age 60
· Being black, Asian or Hispanic
· Having a family history of glaucoma
· Having certain medical conditions, such as diabetes, heart disease, high blood pressure and sickle cell anemia
· Having corneas that are thin in the center
· Being extremely nearsighted or farsighted
· Having had an eye injury or certain types of eye surgery
· Taking corticosteroid medications, especially eyedrops, for a long time
These self-care steps can help you detect glaucoma in its early stages, which is important in preventing vision loss or slowing its progress.
· Get regular dilated eye examinations. Regular comprehensive eye exams can help detect glaucoma in its early stages, before significant damage occurs. As a general rule, the American Academy of Ophthalmology recommends having a comprehensive eye exam every five to 10 years if you're under 40 years old; every two to four years if you're 40 to 54 years old; every one to three years if you're 55 to 64 years old; and every one to two years if you're older than 65. If you're at risk of glaucoma, you'll need more frequent screening. Ask your doctor to recommend the right screening schedule for you.
· Know your family's eye health history. Glaucoma tends to run in families. If you're at increased risk, you may need more frequent screening.
· Exercise safely. Regular, moderate exercise may help prevent glaucoma by reducing eye pressure. Talk with your doctor about an appropriate exercise program.
· Take prescribed eyedrops regularly. Glaucoma eyedrops can significantly reduce the risk that high eye pressure will progress to glaucoma. To be effective, eyedrops prescribed by your doctor need to be used regularly even if you have no symptoms.
· Wear eye protection. Serious eye injuries can lead to glaucoma. Wear eye protection when using power tools or playing high-speed racket sports in enclosed courts.
· Eat a healthy diet. Eating a healthy diet can help you maintain your health, but it won't prevent glaucoma from worsening. Several vitamins and nutrients are important to eye health, including zinc, copper, selenium, and antioxidant vitamins C, E, and A.
· Limit your caffeine. Drinking beverages with large amounts of caffeine may increase your eye pressure.
· Sip fluids frequently. Drink only moderate amounts of fluids at any given time during the course of a day. Drinking a quart or more of any liquid within a short time may temporarily increase eye pressure.
TREATMENTS FOR GLAUCOMA
The damage caused by glaucoma can't be reversed. But treatment and regular checkups can help slow or prevent vision loss, especially if you catch the disease in its early stages.
Glaucoma is treated by lowering your eye pressure (intraocular pressure). Depending on your situation, your options may include prescription eyedrops, oral medications, laser treatment, surgery or a combination of any of these.
Glaucoma treatment often starts with prescription eyedrops. These can help decrease eye pressure by improving how fluid drains from your eye or by decreasing the amount of fluid your eye makes. Depending on how low your eye pressure needs to be, more than one of the eyedrops below may need to be prescribed.
Prescription eyedrop medications include:
· Prostaglandins. These increase the outflow of the fluid in your eye (aqueous humor), thereby reducing your eye pressure. Medicines in this category include latanoprost (Xalatan), travoprost (Travatan Z), tafluprost (Zioptan), bimatoprost (Lumigan) and latanoprostene bunod (Vyzulta).
Possible side effects include mild reddening and stinging of the eyes, darkening of the iris, darkening of the pigment of the eyelashes or eyelid skin, and blurred vision. This class of drug is prescribed for once-a-day use.
· Beta blockers. These reduce the production of fluid in your eye, thereby lowering the pressure in your eye (intraocular pressure). Examples include timolol (Betimol, Istalol, Timoptic) and betaxolol (Betoptic).
Possible side effects include difficulty breathing, slowed heart rate, lower blood pressure, impotence and fatigue. This class of drug can be prescribed for once- or twice-daily use depending on your condition.
· Alpha-adrenergic agonists. These reduce the production of aqueous humor and increase outflow of the fluid in your eye. Examples include apraclonidine (Iopidine) and brimonidine (Alphagan P, Qoliana).
Possible side effects include an irregular heart rate, high blood pressure, fatigue, red, itchy or swollen eyes, and dry mouth. This class of drug is usually prescribed for twice-daily use but sometimes can be prescribed for use three times a day.
· Carbonic anhydrase inhibitors. These medicines reduce the production of fluid in your eye. Examples include dorzolamide (Trusopt) and brinzolamide (Azopt). Possible side effects include a metallic taste, frequent urination, and tingling in the fingers and toes. This class of drug is usually prescribed for twice-daily use but sometimes can be prescribed for use three times a day.
· Rho kinase inhibitor. This medicine lowers eye pressure by suppressing the rho kinase enzymes responsible for fluid increase. It is available as netarsudil (Rhopressa) and is prescribed for once-a-day use. Possible side effects include eye redness, eye discomfort and deposits forming on the cornea.
· Miotic or cholinergic agents. These increase the outflow of fluid from your eye. An example is pilocarpine (Isopto Carpine). Side effects include headache, eye ache, smaller pupils, possible blurred or dim vision, and nearsightedness. This class of medicine is usually prescribed to be used up to four times a day. Because of potential side effects and the need for frequent daily use, these medications are not prescribed very often anymore.
Because some of the eyedrop medicine is absorbed into your bloodstream, you may experience some side effects unrelated to your eyes. To minimize this absorption, close your eyes for one to two minutes after putting the drops in. You may also press lightly at the corner of your eyes near your nose to close the tear duct for one or two minutes. Wipe off any unused drops from your eyelid.
If you have been prescribed multiple eyedrops or you need to use artificial tears, space them out so that you are waiting at least five minutes in between types of drops.
If eyedrops alone don't bring your eye pressure down to the desired level, your doctor may also prescribe an oral medication, usually a carbonic anhydrase inhibitor. Possible side effects include frequent urination, tingling in the fingers and toes, depression, stomach upset, and kidney stones.
Surgery and other therapies
Other treatment options include laser therapy and various surgical procedures. The following techniques are intended to improve the drainage of fluid within the eye, thereby lowering pressure:
· Laser therapy. Laser trabeculoplasty (truh-BEK-u-low-plas-tee) is an option if you have open-angle glaucoma. It's done in your doctor's office. Your doctor uses a small laser beam to open clogged channels in the trabecular meshwork. It may take a few weeks before the full effect of this procedure becomes apparent.
· Filtering surgery. With a surgical procedure called a trabeculectomy (truh-bek-u-LEK-tuh-me), your surgeon creates an opening in the white of the eye (sclera) and removes part of the trabecular meshwork.
· Drainage tubes. In this procedure, your eye surgeon inserts a small tube shunt in your eye to drain away excess fluid to lower your eye pressure.
· Minimally invasive glaucoma surgery (MIGS). Your doctor may suggest a MIGS procedure to lower your eye pressure. These procedures generally require less immediate postoperative care and have less risk than trabeculectomy or installing a drainage device. They are often combined with cataract surgery. There are a number of MIGS techniques available, and your doctor will discuss which procedure may be right for you.
After your procedure, you'll need to see your doctor for follow-up exams. And you may eventually need to undergo additional procedures if your eye pressure begins to rise or other changes occur in your eye.
Treating acute angle-closure glaucoma
Acute angle-closure glaucoma is a medical emergency. If you're diagnosed with this condition, you'll need urgent treatment to reduce the pressure in your eye. This generally will require both medication and laser or other surgical procedures.
You may have a procedure called a laser peripheral iridotomy in which the doctor creates a small opening in your iris using a laser. This allows fluid (aqueous humor) to flow through it, relieving eye pressure.