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GLAUCOMA GLAUCOMA AND THE GLAUCOMA SPECIALIST Glaucoma, one of the leading causes of blindness, is estimated to affect 1 of every 50 adults. Although glaucoma can occur at any age, the risk of developing the disease increases dramatically after the age of 40. Glaucoma is also more likely to develop in individuals with a family history of glaucoma. Patients who are severely nearsighted and individuals of African American Ancestry have a greater risk of developing glaucoma. Past eye injuries and a history of severe anemia or shock are additional risk factors. Because there are no warning signs or symptoms of early glaucoma, the disease often goes unnoticed until permanent vision loss has occurred. Most people do not detect a change in their vision until substantial sight loss has occurred . Vision loss typically occurs without any discomfort or pain. Certain parts of peripheral (side) vision are affected first. "Tunnel vision" - a condition in which a person can only see a small area in the center of vision develops as a late stage of the disease. The loss of vision often is so gradual that it often goes unnoticed until it's too late to restore normal vision. If left untreated, total blindness will result.
PREVENTION IS THE BEST MEDICINE Vision loss from glaucoma is permanent but it can usually be prevented with early detection and treatment. Since the symptoms of the disease are often unnoticeable, regular eye exams are important for early detection, especially for persons over the age of 35 or individuals in high risk groups. The important thing to remember is that with early diagnosis and careful treatment, visual damage from glaucoma can be prevented.
WHAT IS GLAUCOMA? Glaucoma is an eye disease which is one of the leading causes of blindness in the United States. Glaucoma is fairly common in adults over age 35. Two out of every 100 persons in this age group have vision threatened by this disease. When diagnosed early, blindness from glaucoma is almost always preventable. When we look at an object, the image is carried from the retina to the brain by the nerve of sight (the optic nerve). This nerve is like an electric cable. It contains a million wires, each carrying a message to the brain, which join together to provide side vision, as well as sharp, central reading vision. Glaucoma can produce damage to these "wires," causing blind spots in areas of vision to develop. People seldom notice these blind areas in the side vision until considerable optic nerve damage has occurred. If the entire nerve is destroyed, blindness results. Fortunately, this rarely occurs if glaucoma is diagnosed and treated before major damage has taken place. The glaucomas are a family of eye diseases which have in common a characteristic progressive optic neuropathy with associated visual field loss.
There are several risk factors for the development of glaucoma. Risk factors: 1. Elevated intraocular pressure
HEREDITY OF GLAUCOMA Some glaucomas run in families. If one parent has open - angle glaucoma the chances an offspring will have a similar condition are about 10 times greater than in the non-glaucoma population. But since glaucoma affects only around one-half of one percent of our population, clearly, many offspring will not get the condition. Where visual field loss from glaucoma has occurred in a parent, however, the offspring are definitely more likely to lose sight themselves. This appears especially to be true for those with angle-closure glaucoma, where almost one-third of the offspring may be affected. Brothers and sisters of the affected person are at even greater risk. Genetic lesions which may play a role in the heritable development or predisposition for glaucoma have been recently identified. These include the juvenile congenital glaucoma gene GLC1A, also known as the TIGR gene (trabecular meshwork inducable glucocorticoid response gene) and the buphthalmos familial glaucoma candidate gene GLC3A. Indeed, several of the preceeding risk factors also suggest that there may be a genetic component to the disease in many cases. Glaucoma is not an infection, and it's not contagious. It results from damage to the optic nerve. For more than a century, the main therapeutic goal in glaucoma management has been to remove the risk associated with elevated IOP (risk factor management).
WHAT CAUSES THE DAMAGE The intraocular pressure is created by the fluid in the eye building up to an abnormally high level. When this pressure remains elevated over a period of time, damage occurs to the delicate optic nerve. If left untreated, blindness often results. Glaucoma usually affects both eyes. In order to understand how the increased pressure affects sight, let's first take a look at how the eye works. The front part of the eye (the anterior chamber) contains a clear, nourishing fluid called the aqueous which constantly circulates through the eye. This fluid helps maintain normal pressure inside the eye, preventing the eyeball from collapsing like a balloon without air. It is constantly produced the ciliary body and drains through the trabecular meshwork, where it returns to the bloodstream. Glaucoma develops then the production of aqueous humor increases or the aqueous humor does not drain adequately. The pressure rises in the eye. Nerve fibers and blood vessels in the optic nerve become compressed and can be damaged or destroyed. Consequently, the transmission of visual messages to the brain is interrupted. The result is impaired vision and, ultimately, blindness. While elevated IOP is clearly a risk factor for glaucomatous optic neuropathy, and its reduction often slows or interrupts the disease process, the continued progression of the disease after substantial IOP lowering via medical or surgical intervention suggests that pressure-independent causes may contribute in many cases. Furthermore, glaucomatous optic neuropathy in patients who do not present an obvious IOP component to their disease, ie., patients who have IOP well within the normal range (eg, less than 22 mm Hg), suggests pressure-independent causes.
NEUROPROTECTION: NEW AREA OF RESEARCH IN GLAUCOMA To improve the level of visual preservation, even for those patients which may suffer from pressure-independent causes of their disease, a new therapeutic strategy is evolving, focusing on the affected tissue, ie., the ganglion cells of the retina. This new therapeutic strategy will not only continue to feature IOP lowering, but will also provide direct protection at the common endpoint pathway for injury in glaucomatous optic neuropathies: the optic nerve. New information about how this disease state leads to neuronal cell death is an emerging area of research. Results from this research are providing new targets for drug discovery and therapies focused on directly protecting the optic nerve.
TYPES OF GLAUCOMA There are different varieties of glaucoma. Some of which involve a build-up of pressure inside the eye. Glaucoma can sometimes result from other eye conditions such as inflammation or injury. Rarely, infants are born with the disease. Congenial glaucoma causes noticeable symptoms in the infant such as enlarged and often cloudy eyes with light sensitivity and tearing. However, chronic and acute glaucoma are two broad categories of glaucoma. Chronic glaucoma&emdash;the most common type&emdash;is painless. Left untreated, it slowly destroys vision. In fact, most people who have chronic glaucoma are not aware that they are being robbed of their eyesight since the loss of vision is so gradual. Sometimes there is no build up of pressure at all, this is called normal tension glaucoma. Over 90% of adult glaucoma patients have open - angle glaucoma. In most cases, there are no warning symptoms . By the time vision problems develop, irreversible visual damage may already have occurred. Because chronic glaucoma seldom causes symptoms, it's extremely important for you to have a thorough eye exam around age forty&emdash;even if you have no complaints about your vision. Appropriate follow up exams will then be recommended by your eye doctor depending on the health of your eye.
TREATMENT OF ANGLE-CLOSURE GLAUCOMA Acute glaucoma is not nearly as common as chronic glaucoma. It occurs more frequently in the Native Alaskan Inupic and Inuit. Acute glaucoma is another major form of the disease. Unlike the gradual destruction of vision that occurs in the chronic condition, vision loss is rapid if this condition develops. It is an emergency condition. Eyesight can be lost permanently unless the pressure is relieved within a few hours with medication and surgery. Acute angle-closure glaucoma is treated urgently. Oral or intravenous medication is given at once to relieve the pressure temporarily. Your Ophthalmologist will need to perform either laser or incisional surgery that is appropriate for you. It is as though a sheet of paper floating near a drain suddenly drops over the opening and blocks the flow out of the sink. In the eye, the iris may act like the sheet of paper closing off the drainage angle. When eye pressure builds up rapidly, it is called acute angle-closure glaucoma. The symptoms include:
HOW IS GLAUCOMA DETECTED? Regular eye examinations by your Ophthalmologist are the best way to detect glaucoma. An Ophthalmologist is a medical eye doctor. Your Ophthalmologist can detect and treat glaucoma.
Some of these tests may not be necessary for every person. You may need to repeat these tests on a regular basis, to determine if glaucoma damage is increasing over time.
TYPES AND STAGES OF GLAUCOMA I: GLAUCOMA SUSPECT Glaucoma Possible But Not Proven II: PREGLAUCOMA A. Intraocular pressure above 30 mmHg III: GLAUCOMA PATIENT Glaucoma
HOW IS PRIMARY OPEN ANGLE GLAUCOMA TREATED? With early detection and treatment, glaucoma can usually be controlled and vision preserved. However, glaucoma cannot be cured. Once vision has been lost, it cannot be restored. Hence early diagnosis and treatment is important to minimize vision loss. A combination of eye drops, medication, laser treatment and conventional filtering surgery is used to treat glaucoma. Treatment is concentrated on lowering the pressure inside the eye to prevent damage to the optic nerve. The most common treatment for glaucoma is the use of medication in the form of eye drops and, occasionally, pills. Some drops lower eye pressure by improving the drainage of fluid from the eye. These drops are usually used from one to four times daily. Other eyedrops act to decrease fluid production, and are usually taken once to three times a day. Some eyedrops constrict the pupil, which limits the amount of light that enters the eye and temporarily dims vision. This can be especially troublesome for people with cataracts (cloudy lenses), whose vision may already be impaired. These drops are not used as often. Other eyedrops can cause eye irritation and headaches in some patients, but most people are able to use them without any problems. Eyedrops are absorbed in the bloodstream. As a result, they can affect other body functions as well, so they must be used with caution. Be sure to check with your doctor before taking any other medication. Medications or eye drops typically are the first line of defense in treating glaucoma. Sometimes, eye drops need to be used for the entire duration of the patients life. They are inconvenient to use and most patients find it very difficult to comply with the frequent dosage schedule of eye drops. Allergic reactions can occur to the eye drops. The eye drops can lose their effect over time. This requires stopping the eye drop in question and starting a new one. The pills used to treat glaucoma work by limiting fluid production. The medication is usually taken from two to four times a day. Some people may have tingling in the hands and feet, stomach upset, nausea, or loss of appetite, but most people can take the pills without side effects. Glaucoma medication taken in combination with some drugs can cause side effects, so be sure to let any health care professional that treats you know that you are taking medication for glaucoma. The use of Diamox and Neptazane pills is much less frequent now with the advent of newer eye drops. Often the faithful use of these medications bring the eye pressure under control. For some people, however, these medications cannot successfully control the pressure. Laser surgery or traditional filtering surgery may then be performed to alleviate the pressure and arrest the disease. Sometimes, the glaucoma specialist calls your family doctor and recommends cutting back on your high blood pressure pills or other medications that might cause problems with blood flow to the optic nerve. Sometimes you are sent to a cardiovascular surgeon or internist to have tests to evaluate the circulation to your optic nerve. Because medications and eye drops can cause undesirable side effects or simply fail to control glaucoma, alternative methods of treatment may be needed. In some cases, laser treatment is performed to control glaucoma. A laser is used to improve drainage and reduce fluid pressure. This treatment is called an Argon Laser Trabeculoplasty. A laser is a highly concentrated beam of light energy that is focused to a point and used surgically to treat glaucoma. It is light of a single wavelength&emdash;all the energy works together and in one direction. Because laser light can be controlled so precisely, it is safe and reliable. To improve the flow of fluid through the trabecular meshwork, your doctor will use the argon laser in that area of the eye. You will be given anesthetic drops and asked to rest your chin on the platform that is connected to the slit lamp and the laser. You will be asked to remain still, allowing your doctor to direct the laser to the exact part of your eye where the surgery is needed.
LASER TREATMENT FOR OPEN - ANGLE GLAUCOMA - LASER TRABECULOPLASTY The most common form of open - angle glaucoma in North America, primary open - angle glaucoma, often responds well to a laser treatment known as Laser Trabeculoplasty. With primary open - angle glaucoma (as well as a few other types), the eye pressure becomes elevated because the trabecular meshwork (the sponge-like drain) becomes progressively clogged with the passage of time. This causes eye pressure to increase and threatens the optic nerve. Many cases can be treated with eye drops or pills, some of which unclog the drainage tissue. When tolerated medicines have not been sufficient to lower the eye pressure to a safe level, your ophthalmologist may recommend that laser trabeculoplasty be performed.
HOW DOES LASER TRABECULOPLASTY WORK? Neither the exact mechanism by which the drainage is clogged in glaucoma nor unclogged by laser is precisely understood. Although some lasers can cut holes in tissue, that mechanism is not used for treating the usual forms of open angle glaucoma in adults. The pressure lowering from laser trabeculoplasty occurs as a complex biological response of the drainage tissue to the laser energy. The heat of the laser may shrink and mechanically alter the shape or position of the tissue. Laser also alters the activity of the cells in the drainage area, probably stimulating their natural housecleaning, unclogging activity.
WHAT HAPPENS WHEN I HAVE LASER TRABECULOPLASTY? With laser trabeculoplasty, the laser is focused through a special contact lens prism to make tiny burns directly on the surface of the drainage tissue. About 50 to 100 such burn spots are placed over either half of the entire ring-shaped drainage area. Each spot is flashed for much less than a second and is pinpoint in size. Thus, no real pain is encountered, although some patients will feel an occasional pin prick sensation. No preoperative sedation and no anesthesia are required, except for an eye drop to allow placement of the contact lens. The procedure itself takes from 15 to 30 minutes. The patient is usually asked to remain in the office for awhile afterwards so that the eye pressure can be checked. The final amount of pressure lowering does not take place immediately. The pressure during the first few hours afterward may be quite low or QUITE HIGH. In the latter case, medicines to immediately lower eye pressure may be necessary. The maximum long-term pressure lowering may not be evident for up to six weeks after completion of the procedure.
WILL LASER TRABECULOPLASTY CURE GLAUCOMA? Neither laser treatment nor any other treatment will cure glaucoma. Open angle glaucoma is a progressive clogging of the eye fluid drainage tissue. Laser simply unclogs the tissue at the time of the treatment and during the weeks following it. This results in a lowering of the eye pressure in over 75% of treated eyes. However, the fundamental glaucoma process of drainage obstruction cannot be permanently eliminated and the drainage area may again gradually become clogged during the years following the procedure. Laser trabeculoplasty successfully controls the eye pressure at a safe level for at least three to five years in about half of treated eyes. Argon laser Trabeculoplasty (ALT) is done with the Argon laser. It consists of placing 100 small burn spots (50 microns in size) in the trabecular meshwork 360 degrees around the eye. This is thought to be generally temporary and results in a pressure lowering or 4-5mm of Hg. It is generally done in 2 settings, 180 degrees at a time. This can be painful, and anti-inflammatory drops are used post-operatively. The procedure takes about fifteen to thirty minutes. After surgery, you may go home and resume your normal activities. Your doctor may want to check your eye pressure later that same day. It may take a few weeks for the full effect of the laser treatment to be seen, and you may need to continue taking medication. It is possible that trabeculoplasty may have to be repeated at a later time. Sometimes the pressure lowering effect diminishes over time. Traditionally, eye drops and/or laser treatment have been tried first. If these methods failed to decrease fluid pressure, then conventional filtering surgery was done to create a new drainage channel, called a Trabeculectomy.
WHAT TO EXPECT WITH GLAUCOMA SURGERY PRINCIPLES AND PURPOSE Trabeculectomy is the most widely performed type of glaucoma surgery. It is usually recommended when the eye pressure cannot be lowered enough with medical and/or laser treatment. Another name for trabeculectomy is "filtering surgery," because a new drain for fluid, or "filter," is created within the wall of the eye. This drain is usually located at the top portion of the eye underneath the upper eyelid. After surgery, the eye fluid drains through the newly created passage to a reservoir, known as the bleb. This is created at the time of surgery from the outer coats of the surface of the eye. This bleb appears as a "blister-like" bump on the white of the eye, usually under the upper eyelid. The appearance of the bleb is used by your surgeon to judge the condition of the eye and success of the surgery.
THE SURGERY Trabeculectomy is performed in an operating room on an outpatient basis. A local anesthetic, which is given by injection at the site of the eye, is used to prevent discomfort during the operation. Sedation might also be given before the anesthetic to relax you. The surgery is performed while you are lying on your back, with your head supported on a pillow. Except for the eye, the face is covered with a sterile sheet that is draped over a bracket to assure the nose and mouth are open for normal breathing. The surgery requires a special microscope which is suspended over the eye. This enables your eye surgeon to see clearly the very fine details of the eye. Tiny stitches, thinner than a human hair, are used to close the surgical incision. Sometimes a drug to reduce scarring (an antimetabolite) is applied during surgery. Trabeculectomy usually is performed in less than 1 hour. It may take longer if there has been previous eye surgery, inflammation, abnormal blood vessels, or other eye problems.
AFTER SURGERY Immediately following trabeculectomy, the eye is soft and delicate. Your physical activity should be restricted to avoid lifting, bending, and straining. Vision is usually quite blurred during the recovery period. Your care after the surgery is as important to the long-term success of the operation as the surgery itself. Most surgeons prefer to provide that care themselves, so that they may observe the earliest signs of any problems. Each person heals differently after surgery. Therefore, your care must be individually adjusted depending on the appearance of the bleb and the condition of the eye. Patients are typically seen several times during the first 6 weeks following surgery. If problems occur, they are noted during this time. As the eye heals, it is not necessary to be seen as much.
COMMON CONCERNS AFTER TRABECULECTOMY 1. VISION Although the operation is done to preserve vision, it is not designed specifically to improve vision, only to lower eye pressure. Typically, vision is quite blurry during the first days to weeks after surgery. Sometimes fluid collects in the back of the eye and further blurs the vision. This fluid can move around within the eye, causing marked changes in vision with time of day or head position. Profound sudden loss of vision, especially with severe pain, often means bleeding in the back of the eye. Permanent loss of vision can follow glaucoma surgery, but it is rare.
2. PAIN Pain is unusual after trabeculectomy. Tylenol or its equivalent is usually sufficient to reduce eye pain. Aspirin should be avoided immediately following surgery. Eye irritation or mild discomfort is common. Atropine (a drop in a red bottle) relaxes muscles within the eye and effectively reduces pain in most circumstances. Sudden, severe, deep-seated eye pain, associated with loss of vision, often means a hemorrhage in the eye and should be reported to your surgeon. Feeling something in your eye or itching are common from the stitched wound. When the bleb, the newly created eye fluid reservoir, protrudes from the surface of the eye (as it commonly does) you may have a dry spot on the front of the eye and feel like there is something in your eye. This is usually relieved with eye lubricant drops or ointment.
3. EYE PRESSURE The purpose of the operation is to lower eye pressure. Pressure is lowered by directing the eye fluid to the newly created reservoir or bleb. The healing of the eye and formation of the bleb takes weeks to months to develop and may even change 1 year later. During the first few days after surgery, eye pressure is usually quite low. Typically, it gradually rises over the first several weeks after surgery. The exact value during the first 10 days probably has no bearing on the final outcome. Later, eye pressure may rise too high, and your surgeon may need to adjust your therapy. When high eye pressure persists after surgery, it is often the result of a large scar forming within the outer coat of the eye and impeding the drainage of fluid from within the eye. A conjunctival and tenons flap is carefully prepared. A small microscopic portion of the sclera is fashioned into a flap. A full thickness section of the remaining scleral bed and trabecular meshwork is removed to enable the fluid to drain from your eye and reduce intraocular pressure. The small, microscopic hole in the scleral bed is closed over by suturing the above fashioned scleral flap back down. The conjunctival and tenons flap is then closed down over this and fluid perculates out of the eye. A local or general anesthetic will be used. After surgery, you probably will go home that day and rest. Your doctor will want to see you the next day to check your vision and eye pressure. You will need to use medication after your treatment. Filtering surgery is done much earlier in glaucoma cases now than in the past. With the advent of the anti-scarring medications called mitomycin and 5 fluro-uracil (5 FU) the success rate of filtration surgery is now thought to be around 85%. However, this requires meticulous surgery and extensive follow up time. It also can require additional injections of 5-FU after the surgery. Sometimes cutting of the sutures with the argon laser is also necessary. Sometimes, injection with blood into the filtering bleb is necessary or additional surgery if over filtration occurs. The success rate of this surgery is higher if little or no medication (eye drops) has been used in the past. This is thought to be due to the drops causing white blood cells to infiltrate the conjunctiva and tenons, the area where the filtering actually occurs. Sometimes just simply removing a cataract will result in better intraocular pressure control with conventional medications (eye drops). Sometimes an endoscopic laser treatment is done in conjunction with cataract surgery. Endoscopic laser treatment consists of a small fiber optic wand being placed inside the eye at the time of cataract surgery. The wand has a fiber optic light source bundle, a fiber optic camera bundle, and a fiber optic diode laser bundle. This allows the surgeon to direct the tip of the wand directly at the front row of the ciliary processes under direct visualization on a T.V. monitor. This ciliary processes are responsible for the production of fluid of the eye. By thermally ablating a portion of the ciliary processes less fluid is produced in the eye. This results in a lowering of the intraocular pressure. The results of this treatment are not as predictable as traditional filtration surgery. Sometimes a tube shunt is used to lower intraocular pressure instead of filtration surgery. This device is typically used in advanced glaucomas, glaucomas due to blood vessel growth or in eyes with too much scarring from previous surgery. A tube shunt is placed surgically on the surface of the eyeball. A small tube is placed into the anterior chamber in front of the iris and connected to the shunt. A piece of graft tissue is placed over the small tube to reduce the chance of erosion. This procedure is not generally done early on in the treatment of glaucoma. It is usually reserved for severe uncontrollable glaucoma when all other procedures fail. In severe and uncontrollable glaucoma sometimes a YAG laser or Cryotherapy is used to treat the exterior of the eye over the ciliary processes that produce the fluid. Abexterno ablation of the ciliary body by the YAG laser is done by focusing the laser on the surface of the eye, over the ciliary body. A YAG laser beam is directed into the ciliary body area of the eye. This results in thermal damage to that portion of the ciliary body. Too much of a pressure lowering affect can occur with this procedure. This is called hypotony. Other complications could include bleeding inside the eye. This procedure is not generally done early on in the treatment of glaucoma and is reserved for severe uncontrollable glaucoma when all other procedures fail. In some rare instances cryoablation of the ciliary body is used. Cryoablation of the ciliary body results when a refrigerated freezing probe is placed on the outside of the eye over the ciliary processes. The surgeon then depresses the foot switch which causes a freezing to occur. The ice ball travels through the eye and onto the ciliary body and destroys a portion of theciliary body. This results in a lowering of the intraocular pressure. The intraocular pressure can sometimes be lowered too much with this method. This is called hypotony. Other complications could include bleeding inside the eye. This procedure is done if all other methods of treatment fail. This procedure is not generally done early on in the treatment of glaucoma and is reserved for severe uncontrollable glaucoma when all other procedures fail. Treatment of glaucoma is usually a lifelong process. Glaucoma management requires frequent monitoring and constant treatment. Since there is no way to determine if glaucoma is under control based on how a person feels or their vision, a person with glaucoma generally should be examined every 3 to 4 months for the rest of their lives. Occasionally, a person may have a "borderline" eye pressure, which means that, although the pressure is elevated, there is no evidence of glaucoma damage. If you are a glaucoma suspect with a borderline pressure, your doctor may not prescribe medication immediately. Instead, your pressure will require monitoring by your doctor so that if changes do occur, treatment can be started. Another broad category of glaucoma is acute narrow angle closure glaucoma. Acute glaucoma is not nearly as common as chronic glaucoma. It occurs more frequently in the Native Alaskan Inupic and Iniut. Unlike the gradual destruction of vision that occurs in the chronic condition, acute glaucoma is marked by sudden, severe pain in and around the eye, sharply decreased vision, and often nausea and vomiting. In order to alleviate the pressure and prevent further eye damage, emergency treatment-usually laser surgery or traditional surgery-is required. Acute glaucoma is another major form of the disease. It is an emergency condition. Eyesight can be lost permanently unless the pressure is relieved within a few hours with medication and surgery (laser iridotomy or surgical iridectomy). Acute glaucoma is also known as "narrow-angle" or "closed-angle" glaucoma because the angle where the iris and cornea meet becomes so narrowed that these structures close off over the trabecular meshwork. This blocks the drainage passageway and the pressure climbs to dangerous levels. An acute attack usually occurs without warning and, unlike chronic glaucoma, it usually is accompanied by symptoms and affects one eye initially. Pain in the eye and face, impaired vision, rainbow-colored halos around lights, headache, nausea, and vomiting are common. Elective surgery to prevent an attack in your other eye may be recommended.
SURGICAL TREATMENT Oral or intravenous medication is given at once to relieve the pressure temporarily. As soon as pressure has dropped to a safe level, your Ophthalmologist will perform the surgery that is appropriate for you. Laser iridotomy is an outpatient procedure that involves the use of the laser, a highly concentrated beam of energy, that can be focused to a point and used surgically to treat glaucoma. You will be awake during the procedure, seated at equipment used in the office for an examination. During laser iridotomy, your doctor makes tiny openings in the iris with a YAG or argon laser, allowing fluid to flow freely from the posterior to the anterior chamber. You will rest your chin on the stand that is attached to the laser equipment, and your eye may be anesthetized. You will be asked to remain still and quiet during the procedure. This enables your doctor to focus the laser on the exact treatment spot in your eye. The laser procedure usually takes less than thirty minutes. After laser iridotomy. You will be able to go home the day of surgery and resume normal activities. Medication may be prescribed. Your ophthalmologist may want to check the pressure in your eye later that say. Laser iridotomy prevents further eye damage by relieving the high pressure, but it cannot restore vision that was damaged during the acute attack. A partial loss of sight in the affected eye is often the consequence of an acute attack.
PREVENTING ANOTHER ACUTE ATTACK If you have an attack of acute glaucoma in one eye, you often will have an attack in the other eye eventually. Your ophthalmologist may recommend preventive laser iridotomy or surgical iridectomy to guard against an attack in the second eye. When either is performed before an acute attack occurs, the chances for successful surgery (preventing loss of vision) are greater.
HOW IS GLAUCOMA DIAGNOSED? In most cases, glaucoma is detected in a routine eye examination before the patient experiences any vision problems. An evaluation for glaucoma is painless and includes checking the pressure or "hardness" of the eye with a tonometer. But just checking the eye pressure is not adequate for detecting glaucoma. The optic nerve must be checked for damage with an ophthalmoscope, an instrument which illuminates and magnifies the back of the eye. A special mirrored magnifying lens called a gonioscope is used to examine the drainage channels for proper fluid outflow. If any sign of glaucoma is detected, the patient's field of vision is tested for blind spots and any shrinkage in peripheral (side) vision. The glaucoma specialist will order the appropriate tests and review all of the risk factors and tests to synthesize an opinion as to whether glaucoma is present or not. This is all based on years of experience and training of the glaucoma specialist. Sometimes it's impossible to make a clear call of glaucoma and then you are placed in a glaucoma suspect category.
SPECIFIC TESTS FOR DIAGNOSING GLAUCOMA The diagnosis of glaucoma is confirmed by an array of diagnostic tools that allow your eye doctor to identify signs of glaucoma long before you have any symptoms. Your doctor may begin with tonometry, which measures the pressure in your eye. Another important test checks your side (peripheral) and central vision. Your doctor may examine the interior structures of your eye using gonioscopy. Blue and Yellow visual fields, stereo disk photos, black and white nerve fiber bundle photos, and an HRT might also be used.
THE EYE EXAMINATION Medical History. A routine eye examination usually begins with your medical history. It is essential for your doctor to know if other members of your family have glaucoma because the disease tends to be hereditary. You must also be sure to inform your doctor about any medications that you are taking at the present time. A complete history for all of the risk factors will be taken. Vision test. Often a general eye examination begins with a visual acuity test that determines how sharp your vision is. Using one eye at a time, you'll read a chart of letters or numbers of varying sizes from a set distance (often twenty feet). Then you may be asked to view the chart through an instrument known as a refractor. By shining a light through the refractor onto the retina, your doctor can determine if you need glasses. Slit lamp. A slit lamp is a microscope that magnifies and illuminates the cornea, iris, and lens. It aids your doctor in finding conditions such as cataracts and corneal problems. Pseudoexfolliation, Krukenberg spindles, and iris atrophy are all carefully looked for at the slit lamp (microscope). Tonometry. Used to check eye pressure, tonometry can be performed by one of several methods. During applanation tonometry, you sit at a slit lamp that accomodates the pressure-measuring device: a plastic prism that lightly pushes against your anesthetized eye. Gonioscopy. Another test, called gonioscopy, involves gently placing a special lens that contains a mirror on your eye. The doctor can look inside your eye to see the drainage area that can be a problem in glaucoma. Because the area between the iris and the cornea can be seen, this test is especially helpful in determining whether the angle between the cornea and iris has been narrowed. Gonioscopy may help your doctor diagnose the type of glaucoma you have. Ophthalmoscope. After your vision is checked, your doctor will examine the internal structures of the eye, including the optic nerve. Using an ophthalmoscope, a hand-held instrument, the doctor can see changes in the optic nerve that are characteristic of glaucoma. After the routine examination is completed, a series of specially designed tests are given to help in the specific diagnosis of glaucoma. If at this point things look suggestive of glaucoma specialized tests will then be ordered. Visual field tests. Your examination will test your field of vision, including peripheral and central vision. This test is helpful in determining if your vision has begun to be affected-and, if so, to what extent. Your doctor may use the computerized vision test, called the Humphrey visual field analyzer. One eye is tested at a time while the other eye is patched. During the computerized vision test, the examiner will ask you to place your chin on a stand in front of a screen connected to a computer. While looking straight ahead, you press a button whenever a light appears in view. The computer provides a print-out of your field of vision. Sometimes a specialized blue and yellow visual field will be performed with the same instrument but with a yellow background and a blue spot of light. Stereo disc photos. A special video stereoscope camera will be used to photograph the head of the optic nerve as it enters the eye. This is called the optic disc. In the head of the optic disc is a normal small depression called the optic disc cup. Your doctor can check for progressive enlargement of the optic cup, which indicates continuing damage from the elevated eye pressure. Your doctor may also note blood vessel changes in the optic cup, another sign of glaucoma progression. A special camera for photographing the optic nerve is often used during your eye examinations. Your doctor will advise you how often your eyes will need to be checked. Black and white nerve fiber bundle photographs. When the optic nerve is compromised in glaucoma the small individual nerve fibers from the photoreceptors on the retina are damaged and die off. This results in small focal areas or sometimes wedge-shaped areas on the retinal surface to change texture and color, called nerve fiber bundle drop off. We can photograph this with special high-speed film and a special excitation filter or a bright special colored light. We can then examine these photos to detect very early glaucoma changes. These changes preceed the abnormal changes on the standard white visual field or abnormal cupping of the optic disc. The HRT confocal laser scan. The Heidelberg confocal laser retinal scanner is new technology used to qualitatively record the optic nerve head or disc in glaucoma suspects and glaucoma. This new technology measures and reproduces the topography of the optic nerve head in a quantitative manner. This has never before been available for quantitative assessment of the optic nerve. In glaucoma, we look at several things, three of these are the visual field, intraocular pressure, and the appearance of the optic nerve head. In the past, the first two had been quantitative tests and the last only qualitative and subjective. Usually, we take a picture of the optic nerve and compare subjectively what the pictures look like over time to see if changes have occurred. We also look at the optic nerve and come to an opinion whether the optic nerve is normal or abnormal or suspicious. With the advent of the Heidelberg, HRT, we now have numerical indices and quantitative graphs that allow us to make these diagnosis more accurately. When we combine these tests with the new blue yellow visual fields, we can make the diagnosis of glaucoma much earlier. This allows us to start treatment a lot earlier. It has been demonstrated that blue on yellow visual fields pick up damage from glaucoma 5 years earlier than standard white on gray visual fields. There is a very strong correlation between the changes on the blue yellow visual field with the topography changes of the optic nerve head as assessed by the HRT confocal laser. The Heidelberg Retinal Tomography (HRT). The HRT offers doctors new hope in diagnosing glaucoma before noticeable vision is lost. The HRT is a quantitative computerized imaging device that photographs and measures the topography of the optic nerve head. The HRT derives its results by using the principle of a scanning confocal laser. The HRT captures 32 images or optical slices of the optic nerve head and finishing in front of the optic nerve head. These captured images are sent to the HRT's computer for analysis where high-powered image processing algorithms (computer program) convert the individual optical slice images into depth measurements and topographical maps. The HRT results are reported on the optic nerve head report. This three page report provides a complete assessment of the current optic nerve topography, indices and any changes from previous visits. During the test procedure, the patients head sits in a chin rest and the forehead is rested against a forehead plate while the HRT operator captures images of the optic nerve head, or any area of the retina. The patient views a target while the operator uses a joystick and angling of the laser head to align the HRT on the optic nerve head. The HRT operator is doing all of this while viewing the optic nerve head on a remote video screen. To capture an image, the operator presses a button. Several images are typically recorded, always at least three images are captured. From the recorded images the operator selects three images with the best optical quality for averaging and analysis. He or she also selects the appropriate baseline image against which to measure change. The computer performs the analysis and prints several optic nerve head reports that show the current topography and its change compared to previous evaluations. The physician evaluates the results. Evaluation of optic nerve head appearance is now an established standard of care in the diagnosis and monitoring of glaucoma. Primary open angle glaucoma, for example, is characterized by the appearance of the optic nerve head which is referred to as the disc. The size of the cup, thinning or notching of the disc rim, progressive change, disc hemorrhage, and nerve fiber layer defects are evaluated. The progression of glaucoma is monitored in part by the appearance of the optic nerve head. Once optic nerve head damage occurs, there is often permanent, non-recoverable loss of at least part of the field of vision. Historically, the diagnostic tools available to monitor the progression of such a disease process have been visual field testing (the graphic plotting of the patient's field of vision), extended ophthalmoscopy (actual visualization of the nerve head), and mono or stereo fundus photography. Visual fields plot the result of nerve head damage after it has occurred. Visual fields data is useful in managing the disease process because it measures nerve function. Extended ophthalmoscopy has provided a subjective means of periodically visualizing the nerve head for indicators of progressive diseases such as disc pallor, cupping (increased indentation of the disc), and disc rim degeneration and estimation of the cup to disc ratio vertically and horizontally. It is subjective because the physician must rely on the memory and documented description or drawing of what the disc looked like at the previous visit. Glaucoma is the leading cause of blindness in people over 60, yet it is a difficult disease to diagnose and to manage. Intraocular pressures are neither adequately sensitive nor specific to test the disease, and appropriate target pressures vary from individual to individual. Visual field tests only confirm loss in vision after 30-50% of the nerve fiber damage has already occurred. Evaluation of the optic nerve head is a mainstay of glaucoma management. However, the accuracy of judgements of progressive cupping and loss of nerve fiber substance just outside of the optic disc has been limited by the subjective nature of the clinical examination. Fundus photography offers the physician a record of the optic nerve head status but he or she must still subjectively evaluate whether the patient has lost nerve tissue from visit to visit. The variability of these results is well documented, and only relatively large changes can be detected. Until the development of optic nerve head topography devices, there has been no way to subjectively document the nerve head topographical changes that normally precede visual field loss. Once all of the above tests have been completed and the above risk factors are noted, the glaucoma specialist synthesizes an opinion of whether glaucoma is present. What goes on in the glaucoma specialist's thinking is weighing each one of the risk factors (strong vs. weak) and weighing each test. All of this is done with an extensive background in training and experience. If glaucoma is diagnosed, your progress will be closely monitored during regular examinations and testing.
IMPORTANT ADVICE IF YOU HAVE GLAUCOMA FOLLOW YOUR EYE PHYSICIAN'S INSTRUCTIONS Use the medicine as often as is advised. If you are bothered by the medication in any way, contact your physician immediately, but continue to use it until you have done so. Your physician will then tell you whether to stop the medicine or continue it. If you do not understand why you need a medication, ask your physician.
BE CERTAIN TO USE THE MEDICINES EXACTLY AS ORDERED Continue to use them at all times even if you are away from home or are ill. Wait at least 5 minutes between taking different types of drops. Ask for instructions if you are unsure.
MAKE SURE THE DROP GOES INTO THE EYE Hold a tissue at the corner of the eye to prevent the drop from running into the nose. If you are unsure of how to do this, ASK. Punctal occlusion, as this is called, is important because it increases the effect of the drops and decreases their side effects. Keep the eye closed for 30 seconds.
DO NOT RUN OUT OF MEDICINE Make sure to have it refilled in time. If the pharmacist states it cannot be refilled, call your physician immediately.
RETURN FOR YOUR SCHEDULED RE-EXAMINATION Most glaucomas are diseases that progress slowly, and the correctness of treatment can only be decided by repeated examinations. If it is impossible for you to keep your appointment, be certain to call your physician so that you can arrange another appointment as soon as possible.
CONSULT YOUR PHYSICIAN AT ONCE If you have blurred vision associated with eye pain, if you see haloes around lights, or if your eyes bother you any other way that concerns you, contact your personal eye physician, or go to a hospital which provides emergency medical eye care.
ENCOURAGE YOUR RELATIVES TO HAVE A MEDICAL EYE EXAMINATION Glaucoma tends to affect more than one member of a family. This is especially true for primary glaucomas. Therefore, your parents, brothers, sisters, aunts, uncles, cousins, and children should be examined.
THERE ARE NO SPECIFIC LIFESTYLE LIMITATIONS If you have glaucoma it is probably not necessary for you to change your manner of living in any way. In rare instances, some medicines make glaucoma worse. Therefore, tell physicians when ordering medication for you that you have glaucoma. Exercise is important. Not only is exercise helpful for preservation of general health, it also can lower intraocular pressure. Being overweight can make glaucoma worse.
KNOW WHAT TYPE OF GLAUCOMA YOU HAVE Some medicine may make glaucoma worse, but this depends on the type of glaucoma. Most patients with open angle chronic glaucoma can take any type of medicine without concern that it will alter control of the glaucoma.
EXCESSES OF MOST TYPES ARE NOT CONDUCIVE TO GOOD HEALTH Similarly, it is best for those with glaucoma to live an active, vigorous, full, but reasonably balanced, life.
CARRY A MEDICAL EMERGENCY CARD THAT STATES WHAT TYPE OF GLAUCOMA YOU HAVE AND THE MEDICATIONS YOU NEED This would help in the rare chance that you might be involved in an accident or other emergency medical problem which might interrupt your medication or lead the examining physician to misinterpret the size of your pupils.
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