Factors for Surgical Intervention
Chat Highlights
October 13, 2004

Norma Devine, Editor

Moderator:  Good evening, Dr. Rick. Tonight we would like to discuss indications for surgical intervention. For instance, under what conditions would a shunt be preferable to a trabeculectomy?

Dr. Rick Wilson:  The indications for a shunt rather than a trabeculectomy would include (1) a well-done trabeculectomy with mitomycin C that failed, (2) a conjunctiva too scarred to elevate a conjunctival flap, (3) neovascularization in neovascular glaucoma not yet quiescent after photocoagulation, but intraocular pressure forces surgery; (4) recurrent episodes of serious intraocular inflammation; (5) aggressive ICE (iridio-corneal endothelium) syndrome; (6) cases in which the inner ostium of the shunt can be placed in front of an anterior chamber IOL (intraocular lens) to avoid vitreous incarceration; (7) contact lens wear essential for the patient.

Moderator:  What indicates that a trabeculectomy would work better than a shunt?

Dr. Rick Wilson:  The indications would be that a low IOP (intraocular pressure) is required to prevent further damage to the optic nerve. Usually, a 30% (Spaeth, Katz) drop in IOP from the level at which the patient was sustaining damage is necessary to stop further damage, and a 40% (Shin) drop is necessary to offer a chance for improvement of visual field. Other indications would be for patients after penetrating keratoplasty, for patients in whom a penetrating keratoplasty will likely be needed, and a higher rate of graft failure.

Moderator:  When is a shunt the better choice?

Dr. Rick Wilson:  A shunt is usually the better choice if the conjunctiva is too scarred, if there is chronic inflammation, if the vitreous is a problem, or if a contact lens is required.

P:  Do the patient's age, general health, and attitude influence the decision about when to proceed with surgical intervention?

Dr. Rick Wilson:  Certainly the patient's attitude is important. Increasingly, research shows that as many as one third of patients who have been told they have glaucoma may not be under treatment at any one time. If people don't take their medicines routinely, then surgery is a much better option.

P:  Are some factors more important than others?

Dr. Rick Wilson:  Age is a concern, especially in the 3 to 18 year-old age group. Those patients heal very rapidly, limiting the effectiveness of surgery.

Moderator:  What can you tell a parent whose 14-year-old son needs surgery?

Dr. Rick Wilson:  The rough-and-tumble style of play in young boys may result in rupture or failure of a filtering bleb. Therefore, shunts are given more consideration than they would otherwise.

P:  What are the restrictions for a young teenager after undergoing shunt surgery?

Dr. Rick Wilson:  When the eye pressure is soft, I advise no gym and no horsing around. That is usually the case for a week or two after surgery, and often again at about three to five weeks after surgery, depending upon whether the doctor controlled the postoperative pressure with a dissolvable ligature (stitches) or a valved shunt. No swimming for three to four weeks if the wounds are healing optimally.

P:  If a patient is using more than three kinds of glaucoma medications, should surgery be considered?

Dr. Rick Wilson:  Yes. It is unusual for a fourth medication to add much to the control of a patient's eye pressure if the patient is already on three medicines. This is true especially if each of these medicines has been proved effective with a one-eyed trial or a trial that compares the pressure during several visits before the visit that the medicine is added, with several visits after the medicine has been added.
P:  What questions should patients who are considering having surgery ask their doctors?

Dr. Rick Wilson:  They should ask: "Are there other options besides surgery?" "How often do you perform this procedure?" "Are you completely comfortable advising me to have the surgery and doing it yourself?"

If there is any hesitation, ask: "Is there someone in the community who can do a better job?"
P:  You once mentioned that a patient could say, for instance, "I have every confidence in you, but my husband (or wife) wants me to get a second opinion."

Dr. Rick Wilson:  Yes. It's always best to be courteous and non-confrontational, yet still get the answers you seek.

P:  I'm 57 years old and take four kinds of eyedrops all day long. I plan to have an SLT (selective laser trabeculoplasty) in November. If that surgery doesn't lower my IOP to the target, should I have a trabeculectomy?

Dr. Rick Wilson:  I can't give a learned opinion without seeing you, but a trabeculectomy with some form of anti-scarring medicine sounds quite reasonable.

P:  I am 29 years old. I use Cosopt twice a day, Alphagan P three times a day, and Travatan at bedtime. My IOPs are 18 mm Hg in both eyes. My doctor has recommended cutting surgery to reduce the pressure. Should I consider SLT?

Dr. Rick Wilson:  At your age, I doubt that SLT would be effective and might increase your IOP. That your doctor is not suggesting SLT first is in his favor, and indicates he is savvy and more interested in obtaining good IOP control for you than just making money.

P:  If a patient has a history of inflammation, how does that affect the decisions regarding surgery?

Dr. Rick Wilson:  If there is a history of recurrent inflammation, I find that a trabeculectomy will work well in the short term, but is not as resistant to the next attack of inflammation as a shunt would be.

P:  I am a 53-year-old highly myopic blue-eyed patient diagnosed with primary open-angle glaucoma years ago. IOPs are consistently 18/20 on a regimen of Alphagan P 3x/day, acetazolamide 250 mg 4x/day, and Lumigan. The Lumigan leaves my eyes very red. After seeing me 5 times (the last 3 times at six-month intervals) without observing any deterioration in my visual fields, the glaucoma specialist has gone from suggesting SLTs to insisting on trabs. The reason is the extreme reaction to Lumigan, the need to get off the acetazolamide, and the probable need for drops after SLT. This is according to my second-opinion doctor.

Perhaps the trabs are my best long-term solution. However, I am fair, highly myopic, and blue-eyed, and have eyes that are quite inflamed -- all high risk factors. Would my best choice be SLTs or trabs?

Dr. Rick Wilson:  Unless you have pigmentary glaucoma, the chances of an SLT working for any length of time are low. Have you tried Xalatan? Xalatan often causes much less in the way of red eyes than Lumigan. Also, I never use acetazolamide long term any more. The drops are almost as effective and don't have the systemic problems of decreased energy and appetite, metallic taste, etc. If you are allergic to the drops (which is unlikely if you are not allergic to Alphagan P) and your doctor looked for the telltale signs of Alphagan allergy causing your red eye, then I would certainly agree that surgery is your best option.

P:  I can't tolerate any of the available medications, and am considering having an SLT. If the SLT fails to control my pressures, and a new medication becomes available, would I be able to return to medications?

Dr. Rick Wilson:  Yes. If you are allergic to all available medications, it is likely you are allergic to the preservative that is in most of them. Timoptic is made by Merck without preservatives. It is expensive, but it has saved at least a handful of my patients from surgery.

P:  How long can a patient continue to take Diamox before you consider surgery?

Dr. Rick Wilson:  A week to a few months, depending upon the circumstances.

P:  Are the blebs (surgically created drains) created by trabeculetomies visible?

Dr. Rick Wilson:  The first time, the trab is done at the12:00 o'clock position under the upper eyelid, and most of the time is hidden there. If the bleb is too large, which is usually unpredictable, then it may be visible on one or both sides of the cornea. If the bleb shows, the eye may have a watery, glassy appearance.

P:  My blebs are under my upper eyelids and are invisible.

P:  I told my doctor that if there was a beauty contest for blebs, I'd win.

Dr. Rick Wilson:  As I tell my patients, beauty is in the eye of the beholder, and the blebs look beautiful to me.

End of highlights for October 13, 2004.

On October 20, Dr. Werner discussed "Advanced Glaucoma" in the Chat room. Click here for highlights of that meeting.

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