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Glaucoma

Glaucoma Facts & Questions

 Q   What is glaucoma?

 A   Glaucoma is a condition in which there is irreversible damage to the optic nerve, which can eventually result in blindness.


 Q   Is "high" eye pressure the cause of glaucoma?

 A   There are many types of glaucoma and many causes. Most patients with glaucoma do have elevated eye pressure; however at least a third of the patients with glaucoma may have pressures in the normal or even low region.


 Q   What causes glaucoma?

 A   When glaucoma is related to elevated pressure, a blockage of the drainage canals from the eye is the most common cause. This blockage can be caused by several factors, but most commonly it is a result of aging in normal individuals. When more fluid (aqueous) is produced than runs out of the eye, the pressure elevates.


 Q   Is there more than one type of glaucoma?

 A   Certainly. There are probably 70 to 80 different types of glaucoma. Some are associated with specific diseases and some are associated with injuries. The most common type is known as primary open angle glaucoma and probably represents 75% of all glaucoma. Another large group of glaucomas are known as angle closure glaucomas and these glaucomas typically require laser to treat them.


 Q   Don't some people have high pressure yet don't have damage?

 A   Yes. There is a large group of people called “ocular hypertensives” who have high pressure, but for some reason their nerves do not seem to be particularly susceptible to damage. These patients still need to be followed with visual fields and regular examinations because a certain number of them will develop glaucoma damage as time passes and, certainly, those people need to be treated.

Recently, data was published from the Ocular Hypertensive Treatment Study (OHTS). In this study, half the people with elevated pressures received medications and half the people did not. After seven years, 9% of the patients who did not receive any treatment had a very small degree of damage from glaucoma. This compares with a group that was treated and only 5% developed damage. There are many different ways to interpret this data, but probably the most important point to remember is that 90% of the people did not develop damage during the seven years of the study and the damage was caught very early. Another interesting factor is that patients who had thick corneas, which is measured by a test called pachymetry, were found to be less likely to get damage than those patients with thin corneas.


 Q   What is normal pressure?

 A   This question is difficult to answer. Think about a person’s weight. If you are told a patient weighs 170 pounds, you don’t know whether that person is overweight or underweight. It depends on the number of factors including height, build and sex. Eye pressure is very similar. For some people, a pressure of 24 mmHg may be okay and in other patients, a pressure of 18 mmHg could be critically high. In reality, what a patient should be interested in is what is a safe pressure for them.


 Q   If I have glaucoma, will I go blind?

 A   Treatment and regular follow-up is quite effective in preventing blindness from glaucoma in one eye. Studies have shown that one-third of people who eventually go blind from glaucoma are actually blind at the time of their initial diagnosis. The only way these patients could have been helped would have been if they had sought treatment or screening earlier. Another third of the patients who go blind from glaucoma do not participate fully in their treatment. They fail to follow their treatment recommendations or keep regular appointments. That leaves only a small portion of patients who lose vision if they continue their treatment with their doctor.


 Q   How do I know if my glaucoma is controlled?

 A   Glaucoma is very rarely painful, even when the pressure is elevated. Regular eye examinations that include pressure checks, visual fields and nerve examination will help decide if treatment is adequate.

Your doctor will dilate your eyes periodically and look directly at the optic nerve. When glaucoma is uncontrolled, very specific changes in the nerve occur (cupping). Photographs are often taken to help document changes in the nerve.

Visual fields are one of the most reliable methods to track glaucoma progression. Regular examination of the visual field may help detect damage years or decades before it affects central vision.

Other tests of the optic nerve, such as GDx, OCT and HRT may help treat glaucoma damage.


 Q   But what if I hate visual fields?!

 A   They are the single most important glaucoma test for most people. Twenty minutes once or twice a year is a small price to pay to preserve vision.


 Q   I see well - how can I have glaucoma?

 A   Glaucoma tends to affect peripheral vision first, and as such you can have a loss of as much as 90% of your vision before it begins to blur. In general, blurred vision is more likely to be related to macular degeneration, glasses, corneal disease or cataract. Only by closely looking at the nerve or the visual fields can glaucoma damage be detected.


 Q   Does glaucoma run in families?

 A   Many people will tell us “no one in my family has glaucoma.” There doesn’t have to be a family history. On the other hand, family members of people with glaucoma are more likely to have glaucoma. Interestingly enough, brothers and sisters of patients with glaucoma are more likely to have glaucoma than children, and we think that it is very important that all brothers and sisters of patients with glaucoma have an examination for glaucoma.


 Q   I think I am too young to have glaucoma. At what age do people develop glaucoma?

 A   People of all ages have glaucoma. Rarely, glaucoma is diagnosed in an infant at the time of birth. Glaucoma such as this usually requires surgery. Other types of glaucoma may present in young children and teenagers or young adults. Glaucoma becomes significantly more common as people near their mid-40s, but becomes more common throughout lifetime and may not be detected until somebody is in their 80s or 90s.


Treatment

 Q   How is glaucoma treated?

 A   Drops, laser and surgery may all be effective in treating patients with glaucoma.


Eye Drops

 Q   How do I use eye drops?

 A   There are many ways to use eye drops. The most important thing to remember is never use two eye drops within five minutes of each other, as they will wash each other out! It is good to know that the eye only holds 1/8 of a drop so if only part of a drop falls in the eye, that is plenty.

The most effective way to use the drops is to look up, put one drop in the eye and then close the eye for 30 to 60 seconds to give the drop time to soak in. Some doctors also recommend “punctal occlusion” where the index finger is used to press on the inner corner of the eye to help hold the drops in.


 Q   Does it matter whether I put the drop in the lower part of the eye or the inner and outer corner?

 A   No. Once the eye closes, the drop is completely spread out over the surface of the eye. Put it in where it is easiest for you to use.


 Q   Sometimes I have trouble knowing when the eye drop has gone in.

 A   For some people, it helps to store the eye drops in the refrigerator, as the cold drops are easier to feel when they touch the eye.


 Q   Do the drops need to be refrigerated?

 A   Although high temperatures, particularly in cars during the summer, are harmful to the drugs, none of the commonly available glaucoma medications need to be refrigerated.


 Q   Do the drops have side effects?

 A   Certainly. All medications can have side effects, but with eye drops, most patients don’t have serious side effects and the side effects can easily be tolerated.


 Q   What are some common side effects?

 A   The prostaglandin drugs, Xalatan, Lumigan and Travatan, frequently cause redness, eyelash growth and darkening of the iris.

Carbonic anhydrase inhibitors, Azopt and Trusopt, frequently cause stinging.

Alphagan is noted for causing redness, allergy and fatigue. Beta blockers, Timoptic, Timolol and others, are most noted for having systemic side effects. They can affect heart rate and breathing, and although this sounds concerning, these drugs have a long track record and are generally well tolerated.

Pilocarpine is noted to cause headaches and blurred vision.

Some people take pills for glaucoma. There are two very effective pills, which are sold under the name of Diamox and Neptazane. The value of these medications should never be underestimated; however, these tend to have more systemic side effects than any of the other medications we use.


Laser

 Q   Don't some people have laser for glaucoma?

 A   Yes. First of all, it is important to remember the term “laser” may refer to 10 or 15 types of eye procedures that are done for a variety of diseases including nearsightedness, diabetes and macular degeneration. Saying that somebody had “laser” is like somebody who went to their family doctor saying they had an “injection.” There are many different things which could have been done.

For glaucoma, there are generally three types of laser. These lasers include laser trabeculoplasty (ALT), laser iridectomy (LPI) and cyclophotocoagulation (CPC). For typical cases of glaucoma, laser trabeculoplasty is the most common procedure. This is a treatment where 60 to 120 spots of laser are placed inside the eye on top of the drains. They increase fluid flow by approximately 20% and lower pressure a similar amount. This is effective in 80% of patients. A newer laser, selective laser trabeculoplasty (SLT), has similar effectiveness, but may have some advantages as it is possibly felt to be a treatment that could be repeated on a yearly basis, while laser trabeculoplasty is generally only performed once.


Surgery

 Q   Neither laser or eye drops has lowered my pressure and my visual fields are getting worse. Am I going to go blind?

 A   Surgery for glaucoma is one of the most effective treatments that we have. The doctor can cut a small hole in the wall of the eye and make a small drain. This is sometimes called a filter or trabeculectomy. This opening will bypass the normal drain of the eye and allow more fluid to escape and lower the pressure. Very few operations are perfect. While the operation will last forever in some people, the fact is the eye will do everything in its power to try to seal the opening. If the opening does seal, the pressure will go up. Fortunately, the opening will stay open in approximately 85% of the best cases.


 Q   What are "best cases?"

 A   The best cases are eyes which have had no other eye disease other than glaucoma and have had no other surgery. We know we have a lower success rate in particularly young patients, African-American patients, and patients with uveitis or previous surgery.

In many of these cases which have a lower success rate, we are able to use drugs such as Mitomycin C and 5-Fluorouracil that reduce the scarring and increase the success rate. These are potent drugs and there are both pluses and minuses of using them during the period around eye surgery.


 Q   Can the surgery be repeated?

 A   Yes it can. Patients can successfully have a second or even a third operation if the first is not effective. In some cases, it is even possible to operate and place a small tube inside the eye to help drain fluid off.


 Q   Will surgery make me see better?

 A   As we said before, most blurred vision is not related to glaucoma, but to other diseases. Because of that and because glaucoma damage is irreversible, it is very unusual for glaucoma surgery to improve vision. This is disappointing, but it is important to have realistic expectations when undergoing surgery.


 Q   Will I have to use medications after surgery?

 A   The primary goal of glaucoma surgery is to lower the pressure in the eye. If no medications are needed after surgery, that is the ultimate operation, but realistically, a significant portion of patients will still have to use some eye drops. If the patient still needs one or two medications after the surgery, but the pressure is controlled, that is still a very successful operation.


 Q   If I have surgery, does that mean I no longer need treatment for glaucoma?

 A   It is possible that you may no longer need eye drops, but close follow-up is needed for the rest of your life. Not all glaucoma operations last forever, and it is possible that a patient’s pressure can increase months, years or even decades after successful surgery. Another complication, which has to be watched for, is an infection. When we cut a hole in an eye and allow fluid to escape from the eye, it is possible the fluid can actually go the other way and move fluid into the eye. Since this fluid may contain bacteria, the eye is at risk for an infection. This is a very serious condition and could cause blindness. Anytime after you have glaucoma surgery, you should pay particular attention to anytime an eye gets red, painful or has blurred vision.


 Q   Do I have to be in a hospital for surgery?

 A   Most surgery is done in an outpatient facility and much of it is done here on the first floor of the Baptist Eye Center building. Only in very rare circumstances do we find it necessary to stay in the hospital after surgery. It is important to reduce activities and not do any bending or lifting in the first week or so during the period when eye pressure is abnormally low and the eye is at higher risk for complications.


 Q   I don't really like to take medications. Should I have laser or surgery?

 A   While glaucoma surgery is very successful, a very careful consultation with your physician should occur before you elect to switch from medical treatment to surgical treatment. Surgery has certain inherent risks such as retinal detachment, severe bleeding or infection. It is possible to go blind from surgery, but it is very rare. On the other hand, when medications are not successful, surgery is a wonderful option, and people have been controlled without medication for over 50 years.