When is laser surgery appropriate in the treatment of glaucoma?
A: Patients are often unaware of the fact that there are a number of different laser treatments applicable to glaucoma, and this serves as a major source of confusion. Angle-closure glaucoma is an anatomic disease. The drain of the eye (the trabecular meshwork) is forced against it, usually by fluid pressure behind the iris, similar to putting a stopper over the drain of a sink. Laser iridotomy is the definitive treatment for angle-closure glaucoma. Medications should be used only as a temporary measure or if the intraocular pressure is still elevated after laser iridotomy has been performed. A second laser procedure, peripheral iridoplasty, is indicated in a small percentage of patients who have a more complicated from of angle-closure glaucoma known as plateau iris, when laser iridotomy is insufficient to eliminate the blockage of the trabecular meshwork by the iris.
In open-angle glaucoma, the trabecular meshwork is functionally impaired. Argon laser trabeculoplasty is the treatment applicable to the various diseases, which fall under the category of open-angle glaucoma. The most common of these are chronic (primary) open-angle glaucoma, exfoliation syndrome, and pigmentary glaucoma. It is still controversial as to what point to intervene with laser trabeculoplasty in open-angle glaucoma. When the procedure was first developed, it was regarded as a step between maximally tolerated medications and surgical intervention. However, over the past 15 years, it has become realized that, whereas some patients tolerate medications extremely well with no side effects whatsoever, others are seriously hampered in their quality of life. At the same time, surgical techniques have advanced and complications have diminished. The Glaucoma Laser Trail, a national multi-institutional prospective study sponsored by The National Eye Institute, shows that initial laser trabeculoplasty, performed in newly discovered chronic open-angle glaucoma patients prior to the institution of any medical therapy, compared favorably over a two year follow-up over eyes treared initially with medications. However, at the present time, most glaucoma specialists do not perform laser trabeculoplasty as the primary mode of therapy, but rather only if medical therapy is insufficient to control the disease. New medications approved for use in the past two years include apraclonidine (lopidine) and dorzolamide (Trusopt). Patients who have no detectable optic nerve or visual field damage are not candidates for laser trabeculopasty at the present time.
What would the intraocular pressure be in a typical patient when laser surgery would be an appropriate decision and what are the risks involved?
A: There is no specific intraocular pressure at which laser trabeculoplasty is indicated. The pressure, which is too high for an eye, is that pressure at which glaucoma damage progresses and this is usually in the 20's or 30's. If the pressure is in the 40's, laser trabeculoplasty is unlikely to control the disease and surgery is indicated in most cases. I personally do not believe that laser trabeculoplasty is very useful in nomal tention glaucoma. Laser traeculoplasty is by and large a safe prolonged elevation of intraocilar pressure or severe inflammation.
Is it true that benefits of laser surgery to reduce pressure are temporary?
Q: Is it true that benefits of laser surgery to reduce pressure are temporary and, if so, can the surgery be repeated and how often?
A: Approximately 90% of patients get an initial response to trabeculoplasty and 80% have a response at the end of one year. The procedure wears off at a rate of approximately 10% per year, so that somewhat less than half of patients treated are still under control at the end of five years. However, this certainly is a long enough period of time to make it worthwhile undergoing the procedure. The trabecular meshwork runs circumferentially around the eye for 360 degrees. Many ophthalmologists treat 180, using 50 spots, and if the pressure comes under control, stop at that point. Then, if and where the initial treatment wears off, the second 180 degrees can be similarly treated. Some ophthalologists believe in treating the entire 360 degrees initially. Repeat trabeculectomy, in which an additional treatment superimposed upon the first area of treatment is applied, has advocated. I very rarely do this. Mary patients can get a rise in intraocular pressure instead of a lowering of pressure when the trabecular meshwork is retreated. If the initial treatment of 360 degrees (whether performed in one session or two sessions) is insufficient or the effect wears off, I feel that the next step should be surgical intervention.
After a trabeculectomy, what are the risks involved in participating in recreational sports, such as swimming?
A: Ideally, life for the patient should return to normal approximately six weeks after this surgical procedure. Clearly, caution should be used to avoid any trauma to the eye and it is advisable to wear goggles when swimming.
Would you recommend a second opinion before agreeing to laser surgery?
A: There is no blanket indication for a second opinion. Some insurance companies require one, some patients feel better having one, and some ophthalmologists feel better getting one. It all depends on the situation. In straightforward, uncomplicated glaucomas, it is probably not usually necessary, and in more complicated glaucoma it can be beneficial.
How does laser surgery help glaucoma?
A: There are two types of laser procedures used for treating the most common forms of glaucoma. Argon laser trabeculoplasty is performed in treating open angle glaucoma. It is usually quite effective and generally used after topical medication is unsuccessful in controlling intraocular pressure. In open angle glaucoma, picture a sink with the stopper in and the water continuing to run. Eventually, the sink will overflow. Laser sugary opens the drain so the fluid has a way to drain from the eye. In narrow angle glaucoma or angle closure glaucoma, a laser iridectomy is used to pull the iris (the colored part of the eye) away from the drain from the eye. This procedure is successful in preventing damage from angle closure glaucoma.
Is there a time when laser or traditional surgery for glaucoma will replace taking eye drops and medication to control eye pressure?
Q: Is there a time when laser or traditional surgery for glaucoma will replace taking eye drops and medication to control eye pressure? For a person who only has to take one eye drop and who responds well, surgery may not be an option, or at least a necessary option. However for a person who needs three or more eye drops or who has multiple side effects (headaches, dim vision, upset stomach), surgery seems to be a better option.
A: Over the past decade, doctors have become more interested in laser and surgical approaches to early glaucomatous damage. The National Eye Institute/National Institutes of Health have been involved in nationwide research projects to assess the role of early laser or filtering surgery in the management of glaucoma. The Glaucoma Laser Trial documented the safety and efficacy of laser surgery as a treatment for open angle glaucoma and has contributed to its widespread use. The Collaborative Initial Glaucoma Treatment Study randomizes patients to surgery or medication as the initial therapy for open angle glaucoma. This project is still enrolling patients.
Since glaucoma surgery is relatively safe and effective, it can be used for those people who have to take multiple medications or are intolerant of them. Glaucoma therapy needs to be individualized for each patient and alterations in medical therapy should be discussed with your doctor.
A corrective procedure for glaucoma independently of a cataract correction.
Q: I'd like to know whether it is recommended to do a corrective procedure for glaucoma independently of a cataract correction. How successful is this kind of procedure? Also, what are some of the long-term effects of continuing use of medication such as Pilocarpine? I've been told that it becomes more and more difficult to dilate the eyes. Are there any "natural" approaches to reduce problems due to glaucoma and/or cataracts, which are considered effective by medical research groups, such as vitamin therapy?
A: Glaucoma and cataracts often occur together. Since glaucoma surgery can only prevent further vision loss due to glaucoma, many patients undergo combined cataract and glaucoma surgery to reverse the vision loss due to cataract. The decision to do combined surgery should depend on the severity of the glaucoma, preoperative intraocular pressure control, number of preoperative medications, the type of glaucoma, and the visual disability caused by the cataract. Fortunately, combined cataract and glaucoma surgery is often highly successful.
Long-term pilocarpine therapy can cause adhesions (scar tissue) between the iris and lens of the eye, which results in the characteristic small pupil seen in many patients with glaucoma. This small pupil often cannot be dilated. In general, physicians make decisions about the use of a particular medication based upon its benefits when compared to its potential risks. If an individual can tolerate the occasional blurring of vision associated with Pilocarpine therapy and this drug successfully lowers the intraocular pressure, most physicians would opt for its continued use. On the other hand, medications which prove to have significant side effects should be discontinued.
Although there is no scientific proof that holistic forms of treatment, including vitamins or herbs, affect the course of glaucoma or the development of cataracts, it is always important to remain in good general health. This is especially true if one suffers from diabetes or hypertension, which are known to affect the eye.
Can an operation to correct open-angle glaucoma have some complications?
Q: My doctor has told me that an operation to correct open-angle glaucoma can have some complications. Some of these can be bleeding, infection and blindness. Because of this he is very conservative in his treatment and will only operate if truly necessary. I am very concerned about this should I ever need an operation, but, from all the reading I have done on this subject, I have heard that these operations are very successful. I hope my doctor will not delay in my needing an operation until my vision has been seriously impaired. Needless to say either way, I am worried about the outcome of any future operation.
A: Any intraocular surgery can result in bleeding, infection and blindness. For many years, and actually, until quite recently, glaucoma surgery was considered fairly hazardous and generally regarded as a last resort after the failure of medication and laser treatment to control the disease. Many ophthalmologists are still conservative when it comes to glaucoma surgery.
However, in the past few years, the success of surgery for open-angle glaucoma has markedly improved. The first major reason for this is, the use of antimetabolites, such as 5-fluorouracil and mitomycin C, to decrease postoperative scarring. This has resulted in a significant improvement in the success rate of surgery, particularly in those conditions with previous intraocular surgery, such as cataract extraction, patients with previously-failed filtration surgery, younger patients, black patients, and patients with complicated forms of glaucoma or glaucoma associated with uveitis.
The second advance has been post-laser suture lysis. With this procedure, sutures which are buried under the conjunctiva and which close the flap in the wall of the eye after the trabeculectomy has been performed, can be cut using a laser and a special lens. This has allowed glaucoma surgeons to make the flap tighter at the time of surgery. This prevents too much fluid leaving the eye, which can result in a number of undesirable complications, particularly a flat anterior chamber, which can be a surgical emergency.
As a result of these advances, the success rate has significantly increased and the complication rate has significantly decreased. Hemorrhage is extremely uncommon in an eye which has had no previous surgery. It is slightly more common in eyes which have had previous surgery and the chance of its occurring increases with increasing myopia nearsightedness) in such eyes. Late infections of the filtration site are becoming more common with the use of antimetabolites.
The safety of glaucoma surgery has increased significantly in the past few years and concomitantly, our awareness of the side effects of long-term medications has also increased. At the present time, there is an ongoing multi-institutional study sponsored by the National Eye Institute, know as the Collaborative Initial Glaucoma Treatment Study(CIGTS) [see Eye to Eye Spring 1995 edition -- ed.] comparing the safety and efficacy and the effect on quality of life of initial glaucoma surgery compared to initial medical treatment in patients with newly discovered open-angle glaucoma.
Nevertheless, if the glaucoma is uncontrolled and your visual field is getting worse, the chance of an adverse effect from surgery is less than the chance of your losing vision from glaucoma, and glaucoma surgery is generally advisable in such circumstances.
Surgery vs. Medication
Q: I have received two different opinions about glaucoma treatment - one favoring an operation and the other favoring the use of medicine as much as possible due to the complications of surgery - and I am interested in your opinion. If medication keeps the glaucoma in control, but the side effects are awful or make your quality of life not very pleasant, is an operation a better option? Will there eventually be a medicine or operation for glaucoma that will not have all the side effects? What should a person look for in a good eye doctor as far as treating glaucoma for life? The future just looks a little bleak if you have glaucoma, especially if you get it when you are under the age of fifty.
A: Open angle glaucoma with onset under the age of 50 is usually pigmentary glaucoma or juvenile open-angle glaucoma. Angle-closure glaucoma with onset under the age of 50 is usually caused by plateau iris. It can certainly be psychologically devastating to the patient to receive a diagnosis of glaucoma, but with appropriate treatment and timely intervention, a lifetime of continued functional vision is certainly possible. As with all chronic diseases, one should look for a physician in whom one has confidence and to whom one can relate.
It is certainly not unusual to receive differing opinions about the treatment of glaucoma. Most of us who are glaucoma specialists today probably would have been theologians in the 12th century. There are two important trends in the approach to treatment, which have developed over the past several years that should be taken into account.
Surgical intervention was formerly done as a last resort. It was fraught with complications and the success rate was not all that high. In the past decade, the use of anti-metabolites, such as 5-fluorouracil and mytomycin-C, in conjunction with glaucoma filtration surgery, has markedly increased the rate of success. At the same time, tighter would closure and post-laser suture lysis to titrate intraocular pressure has significantly reduced the complication of a flat anterior chamber, which used to be quite common. In essence, glaucoma surgery is safer and more effective than ever before. Routine trabeculectomy for uncomplicated open-angle glaucoma when performed as an initial surgical procedure in a patient who has not had previous intraocular surgery is a highly effective procedure. The chance of complications or surgical failure increases with previous intraocular surgery, complicated glaucoma, reoperations for glaucoma, and high myopia.
Quality of life is an important fact in the treatment of any chronic disease. Particularly if you have many years left to live, it is important to make a decision as to whether you want to spend those years with side effects, which make you miserable. You should first consider whether there is a way to eliminate the side effects of the medications you are presently taking. For instance, if you are taking pilocarpine eye drops which cause blurred vision and induced myopia, you could consider pilocarpine ocuserts which are extremely well tolerated by younger patients. Simple nasolacrimal occlusion can reduce or eliminate side effects of beta-blockers. If you are taking an oral carbonic anhydrase inhibitor, such as Diamox or Neptazane, you might ask your ophthalmologist about dorzolamide (Trusopt), a recently released topical carbonic anhydrase inhibitor. If none of this is effective and you are still suffering from intolerable side effects, or if your glaucoma is uncontrolled, then surgery is not an unreasonable option.
How long is the recovery time for surgery?
Q: How long should I expect to take off work if I need surgery for pigmentary glaucoma?
A: Laser surgery: 1 day
Trabeculectomy: at least one week, often 2 weeks, possibly longer.
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