Glaucoma is the leading cause of blindness in the United States, especially for older people. It is a degenerative disease that, if left untreated, can cause permanent damage to the optic nerve resulting in gradual vision loss and eventual blindness. Early detection and treatment is the best way to prevent vision loss from glaucoma.
Optic nerve damage from glaucoma is usually caused by an elevated intraocular pressure (IOP). In the healthy eye, a clear fluid called aqueous humor circulates continually, providing nourishment to the tissues and pressure that helps maintain the shape of the eye.
Clear liquid called aqueous humor is constantly being produced within the eye (left). If the drainage angle of the eye is blocked, fluid cannot flow out of the eye (right).
What causes glaucoma?
Normally, aqueous humor flows out of the eye through the trabecular meshwork (TM), near the edge of the iris. However, if the TM is blocked and drainage is restricted, pressure inside the eye increases, the optic nerves become damaged, and vision loss occurs.
Open Angle Glaucoma (OAG) occurs when there is an increase in production of the aqueous humor or a decrease in its drainage. Typically, OAG has no symptoms in its early stages and vision remains normal. As the optic nerve becomes more damaged, blank spots begin to appear in the 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. Over time, the increased pressure destroys optic nerve fibers and peripheral (side) vision.
Closed Angle Glaucoma. Some eyes are formed with the iris (the colored part of the eye) too close to the drainage angle. In these eyes, which are often small and farsighted, the iris can be sucked into the drainage angle and block it completely. Since the fluid cannot exit the eye, pressure inside the eye builds rapidly and causes an acute closed-angle attack.
Symptoms may include:
blurred vision;
severe eye pain;
headache;
rainbow-colored halos around lights
nausea and vomiting
This is a true eye emergency. If you have any of these symptoms, call your ophthalmologist immediately. Unless this type of glaucoma is treated quickly, blindness can result. Unfortunately, two-thirds of those with Closed Angle Glaucoma develop it slowly without any symptoms prior to an attack.
Who is at risk for glaucoma?
Your ophthalmologist considers many kinds of information to determine your risk for developing the disease. The most important risk factors include:
age;
elevated eye pressure;
family history of glaucoma;
African or Spanish-American ancestry;
farsightedness or nearsightedness;
past eye injuries;
thinner central corneal thickness;
systemic health problems, including diabetes, migraine headaches, and poor circulation.
Early detection
Vision loss from glaucoma is permanent, but can usually be prevented with early detection and treatment. Glaucoma management is typically a lifelong process that requires frequent monitoring. Since there is no way to determine if glaucoma is under control based on how a person feels, regular eye checkups are essential. Recommended intervals for eye exams are:
Age 20-29: Individuals of African descent or with a family history of glaucoma should have an eye examination every three to five years. Others should have an eye exam at least once during this period.
Age 30 -39: Individuals of African descent or with a family history of glaucoma should have an eye examination every two to four years. Others should have an eye exam at least twice during this period.
Age 40-64: Every two to four years.
Age 65 or older: Every one to two years.
Glaucoma Therapies
Treatment of chronic Open Angle Glaucoma (OAG). OAG is the most common form of glaucoma in the United States and the risk of developing it increases with age. Treatment concentrates on lowering the pressure inside the eye to prevent damage to the optic nerve. The most common treatments for glaucoma have been the use of medications in the form of eye drops or pills, laser therapy, or surgery.
The goal in all glaucoma therapy is to improve the flow of fluid out of the eye through the TM.
Eye drops are commonly used to control glaucoma, however they can be very expensive, messy, and have unwanted side effects including a stinging or itching sensation, changes in pulse, heartbeat or energy level, dry mouth, headaches, blurred vision and others. Never change or stop taking your medications without consulting your ophthalmologist, and consult him or her immediately if you believe you are having side effects.
What’s more, you may need to take them daily for the rest of your life. Some medications reduce the production of aqueous humor, while others enable faster drainage.
Surgical treatments may be required to create a new drainage channel. Filtration surgeries relieve eye pressure by removing tissue, inserting implants in the eye, or a combination of both.
Depending on what your ophthalmologist recommends, surgery for glaucoma is typically an outpatient procedure.
Laser Surgeries
Selective Laser Trabeculoplasty (SLT) is used in Open Angle Glaucoma to treat the drain itself. SLT does not rely on medicines or implants, instead it uses an advanced laser system to target specific cells of the eye – those containing a natural pigment called melanin. Only these cells are affected, leaving surrounding tissue intact. Your body’s own healing response then helps lower the pressure in your eye.
Iridotomy is used in Closed Angle Glaucoma. In this procedure, the laser creates a hole in the iris to improve the flow of aqueous fluid to the drain.
Glaucoma is a disease that affects the optic nerve, the part of the eye which receives images collected by the retina and sends them to the brain. Every eye maintains a certain amount of internal pressure, called intraocular pressure. When this pressure rises to abnormal levels however, it can put extra stress on the optic nerve, causing significant damage. Optic nerve damage results in loss of vision, and ultimately blindness.
The front of the eye is constantly producing a fluid called aqueous humor. A healthy eye will continually produce small amounts of aqueous humor to ensure consistent pressure within the eye. When normal drainage becomes slowed or blocked, pressure increases, and may lead to glaucoma. There are several different types of glaucoma the two most common types being chronic open-angle glaucoma and closed-angle glaucoma.
Chronic open-angle glaucoma is the most common form of the disease and usually develops with age. With this type of glaucoma, pressure gradually increases around the eye causing it to work less effectively over a period of time. There are no symptoms in the early stages of open-angle glaucoma. Peripheral vision is usually the first to deteriorate. As the disease becomes more advanced, blank spots begin to appear in one’s vision. If left untreated, it eventually develops to blindness. The best way to avoid serious vision loss is early diagnosis and treatment.
Risk factors for chronic open-angle glaucoma include:
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Advanced age.
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Family history of the disease.
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Higher-than-normal intraocular pressure.
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Certain ethnic races, particularly those of African descent.
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Certain diseases or conditions, especially diabetes, farsightedness or nearsightedness, or previous eye trauma or surgery.
Closed-angle glaucoma is less prevalent, but is considered a real eye emergency. This type of glaucoma occurs when a patient’s pupil moves or dilates and actually blocks off the drainage angles in the eye. This is considered a medical emergency in which an ophthalmologist should be contacted immediately to avoid any loss of vision.
Symptoms of closed-angle glaucoma include:
High risk factors for closed-angle glaucoma include:
Treatments for glaucoma:
There are a wide range of treatments for the disease, including medication, laser surgery and traditional surgery. The treatment (or combination of treatments) for an individual is chosen based upon the type of glaucoma and other details of the particular case. One option is medication such as prescription eye drops which help to reduce intraocular pressure, or pills called carbonic anhydrase inhibitors which slow down fluid production within the eye.
Laser surgery has also become a common treatment option for glaucoma. For open-angle glaucoma the doctor may choose a trabeculoplasty, a painless laser procedure which uses light to shrink and stretch eye tissue to allow more drainage of fluid. For closed-angle cases, in which the iris is blocking drainage of aqueous humor, a laser surgery called iridotomy may be preformed.
Other glaucoma treatment options involve various traditional surgeries. A common surgery for open-angle glaucoma is the trabeculectomy, where a doctor creates a small flap in the sclera (white part of the eye). Underneath the surface of the sclera, the doctor creates a small reservoir, called a filtration bleb, into which aqueous fluid may drain and then be disbursed, further reducing intraocular pressure.
There are a number of treatments available for Glaucoma patients. If diagnosed with glaucoma, your ophthalmologist will consult with you on your options in order to maintain the best possible health of your eyes.
If you are experiencing any symptoms of glaucoma, we encourage you to contact us today to schedule a consultation.