Recovering From a Trabeculectomy
Chat Highlights
December 1, 2004

Norma Devine, Editor

On Wednesday, December 1, 2004, Dr. Elliot Werner, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Recovering From a Trabeculectomy."

Moderator:  Tonight's topic is "Recovering From a Trabeculectomy."

P:  Doctor Werner, what are the usual restrictions after a trab? 

Dr. Elliot Werner:  We usually ask the patient to avoid heavy work, lifting, or prolonged bending for a week or 10 days.  The patient should try to avoid getting water in the eye, but showering or bathing is okay so long as the eye is protected.  Light activities are okay, but no heavy exercise.

P:  Should sex be avoided after a trab?  If so, for how long?

Dr. Elliot Werner:  Not really.  After a couple of days, sexual activity is okay as long as it is not too vigorous.

P:  How soon after a trab is it all right to sky dive or scuba dive?

Dr. Elliot Werner:  I would probably wait three months, since those are pretty stressful activities.

P:  Do you tell patients to patch the eye at night?  I know I had to patch mine.  I was so frightened I wore the eye patch at night for almost a year!

Dr. Elliot Werner:  We usually don't patch the eye after the first 24 hours.  We advise the use of a plastic shield taped over the eye for a couple of weeks to protect the eye from being bumped while sleeping.

P:  What are the restrictions if the patient has hypotony after a trab?

Dr. Elliot Werner:  Pretty much the same.  There is no good evidence that behavior has any effect on the outcome.  What we try to avoid is straining -- what is technically called a Valsalva maneuver -- so that excessive external pressure is not placed on the eye.  Ordinary activities usually are well tolerated.

P:  What kind of signs indicate that a trab is failing?  

Dr. Elliot Werner:  The signs of failure are flattening of the bleb, inflammation, and increasing intraocular pressure (IOP).  The major issue after trab is inflammation and scarring.  We try to avoid that by using steroids and other anti-inflammatory medications for a fairly prolonged time.  Hypotony (low intraocular pressure) is a problem, but as long as the wound is not leaking, it usually gets better after a while.

P:  What extra medications are prescribed after trabeculectomy?   

Dr. Elliot Werner:  We use steroid drops and sometimes systemic anti-inflammatories, such as steroids or non-steroidals like ibuprofen of indomethacin.

P:  How often does the patient return for post-op checkups?  

Dr. Elliot Werner:  How often you come back depends on how things are going.  My routine for an uncomplicated trab is day one, day five to seven, two weeks, four weeks, six weeks, eight weeks, then three months.  If there are problems, a patient may need to be seen more often. 

P:  If a patient from out of town, where the medical care is not too good, has a trab, how long should he or she stay in the area for checkups?  

Dr. Elliot Werner:  Probably at least two weeks, but the patient would need follow-up after that somewhere.

P:  You mentioned hypotony.   Should the use of mitomycinC be avoided in high myopes?

Dr. Elliot Werner:  High myopia, especially in younger patients, is a significant risk factor for complications after a trab whether or not mitomycinC is used. If there is an indication for mitomycin, it can be used, but the patient needs to be aware of the risks.

P:  Is pain normal after a trab?  I'm now one month post-trab and still have bone pain around the eye socket.  The eyeball also hurts occasionally.  It's not terrible.  Just sort of flickers of pain.  

Dr. Elliot Werner:  Pain is not unusual for some weeks after a trab and can have many causes.  You would need to be carefully examined to determine the source of the pain and to be prescribed the appropriate treatment.

P:  What kinds of complications are there with the use of 5FU (fluorouracil) and mitomycin C?

Dr. Elliot Werner:  The two major complications are hypotony and wound leaks. These can both be more difficult to fix when mitomycinC or 5FU have been used because they inhibit healing.

P:  What's 5FU?

Dr. Elliot Werner:  It's a drug that is used mainly to treat some forms of cancer.  It prevents cells from dividing, which is why it kills cancers and also prevents scarring.

P:  What does bleb failure mean?

Dr. Elliot Werner:  Bleb failure means that the aqueous has stopped filtering out through the opening in the eye wall into the space under the conjunctiva.  It can have several causes, but the most common is scarring of the conjunctiva.

P:  Does bleb failure happen soon after surgery, or can it occur years later?

Dr. Elliot Werner:  Bleb failure can occur early or late.  Early failure is often due to something blocking the opening inside the eye or severe post-op inflammation.  Late failure is almost always due to scarring.

P:  I had a trab and five injections of 5FU that reduced the intraocular pressure.  Three months later, the pressure is rising again.  What can be tried now?   

Dr. Elliot Werner:  That's difficult.  If needling and 5FU injections do not provide a long-term fix, usually you have to go back in and either revise the bleb or do another trab at a different site.  Or use a tube shunt.

P:  I check my bleb every day to look for changes, but I really don't know if I would recognize what a failing bleb looks like.

Dr. Elliot Werner:  Failing blebs become flat and usually vascularize (get red with blood vessels in them).  The main sign of bleb failure, however, is increasing IOP, which would be hard for you to see in a mirror.

P:  What qualifies as high myopia?  Would -6 diopters qualify?

Dr. Elliot Werner:  Usually -5 or more is considered high.

P:  What complications can occur when  a -10 and -9 myope has a trabeculectomy?  I'm getting close to having the surgery. 

Dr. Elliot Werner:  The major complication we worry about in high myopes is hemorrhage.  Myopes are much more prone to severe bleeding in the eye after surgery.

P:  What is a conjunctival buttonhole?

Dr. Elliot Werner:  That's a hole inadvertently cut in the conjunctiva during surgery.  Usually if it is recognized at the time, we try to repair it.  If it is not recognized, it will result in a wound leak.

P:  What's a typical rate of complication (of any type) for a good surgeon?

Dr. Elliot Werner:  Minor complications of one sort or another are very common, because of the nature of the surgery -- probably as high as 40 or 50%.  Serious, sight-threatening complications probably occur about 4 or 5% of the time.

P:  Aren't cataract surgery and trabeculectomy done at the same time?  Can you tell us why or why not?

Dr. Elliot Werner:  Yes, combined procedures are done in patients who have cataracts and glaucoma that is difficult to control.  It is a controversial subject, because the post-op course is longer and more difficult, and the success rate for the trab is less than if you do just a trab alone.  I, personally, don't do a lot of combined procedures for those reasons.  Some surgeons, however, feel they get better results and faster rehabilitation than putting the patient through two operations at different times.

P:  What is the difference between infection and inflammation?

Dr. Elliot Werner:  Infection is a type of inflammation caused by a germ (bacteria, virus, fungus, etc.).  Inflammation is a more general term for a process characterized by redness, pain, swelling, and infiltration of white blood cells.  Infections usually cause inflammation, but not all inflammations are infectious in origin.

P:  What, if anything, can be done to avoid infection or inflammation after a trab?

Dr. Elliot Werner:  To avoid infection, we clean the surgical site with iodine before operating.  The surgeons scrub their hands with sterilizing skin soap for five minutes.  All instruments, drapes, etc., are sterilized.  Operating rooms have special ventilation systems.  We use antibiotic drops after, and sometimes before, surgery.  To prevent inflammation, steroid drops are used routinely after surgery.

P:  How many times can a bleb be revised?  

Dr. Elliot Werner:  My feeling is that if one revision fails, I don't do another, but some surgeons will try a second revision.  I don't think there is anything to be gained by revising a bleb more than twice.

P:  What signs indicate an infection is starting?

Dr. Elliot Werner:  Pain, redness, swelling, decreasing vision, pus discharge from the eye, and pus in the aqueous on slit-lamp exam.  Infections in the eye after trabs are serious complications and often result in complete loss of vision.

P:  What is aqueous misdirection?  Who is more prone to it and how rare is it?

Dr. Elliot Werner:  In aqueous misdirection the aqueous flows backward behind the lens into the vitreous.  It usually occurs after a trab, but can occur after other procedures as well.  It is most commonly seen in people with angle-closure glaucoma and far-sighted patients, although it can occur in anyone.

P:  When your eye itches, is it dangerous to rub it?  I worry about popping the bleb.

Dr. Elliot Werner:  If you are several weeks after the surgery, light rubbing will not affect your bleb.  Hard or excessive rubbing can provoke inflammation, but I don't think you can rupture the bleb like that.

P:  What is overfiltration, when does it occur, and what can be done about it?  

Dr. Elliot Werner:  Overfiltration is a bleb that works too well.  The aqueous flows out of the eye faster than the eye can produce it, so you get a very low IOP.  Sometimes a special type of pressure dressing, called a Simmons shield, is  used.  Some surgeons inject the patient's own blood into the bleb, but in my experience, prolonged overfiltration usually requires a surgical bleb revision to fix it.

P:  What is a suprachoroidal hemorrhage?  Does pain accompany suprachoroidal hemorrhage?

Dr. Elliot Werner:  Suprachoroidal hemorrhage is bleeding between the wall of the eye, between the sclera and the choroid that lies beneath the retina.  It is usually a painful condition, and if the hemorrhage is large, surgery usually is required to fix it.  

P:  What is an encapsulated bleb? Is it a rare occurrence and how is it handled?

Dr. Elliot Werner:  Encapsulated bleb can occur about four to eight weeks after surgery.  It is due to excessive growth of fibrous tissue inside the bleb.  It is not rare and occurs in as many as 25% of trabs.  It is usually self limited and get better on its own, but sometimes requires bleb needling or revision.

P:  What do you consider severe glaucoma?  Would you put a .5 cup/disc ratio in that category?   At what point would vision be impaired? 

Dr. Elliot Werner:  A .5 c/d ratio would not be severe.  I don't use the term "severe," because it is not specific, and does not have an agreed-upon definition in terms of glaucoma.  I prefer to use "early," "moderate," "advanced," or "end-stage,"  because those terms can be quantified by the amount of optic nerve and visual field damage a patient has.

P:  Are eyes more vulnerable to infection than other parts of the body?

Dr. Elliot Werner:  Not really.  The eye, in fact, is pretty good at resisting infection.  The problem is, the eye is so small and the structures so complex that infections are often rapidly progressive and do extensive and irreversible damage unlike in other parts of the body that are large and have more reserve in their function.  For example, you can lose 50% of your kidneys and still function quite well.  Destruction of 50% of the substance of the eye would be devastating.

P:  Does the risk of infection post-trab lessen with the passage of time?

Dr. Elliot Werner:  Good question.  We don't really know.  It depends upon on how thin the bleb is.  Thin blebs are always at risk for infection, and the risk of infection seems to accumulate as time goes on.

P:  Doesn't the risk of infection post-trab increase about 1% per year?

Dr. Elliot Werner:  Not as far as we know.  It doesn't seem to increase as time goes on, but it remains fairly constant.

P:  My 10-month-old daughter had a goniotomy two weeks ago. Why does she need to have steroid drops for a month?  Does this help the incisions to stay open and work?  She has incisions at the 3 and 9 o'clock positions.

Dr. Elliot Werner:  Yes, to prevent infection and scarring and keep the goniotomy incisions open so they won't scar and close up.  The use of steroid for at least a month would be routine.

P:  I'm facing my first trab in January.  It all sounds pretty scary.  Why would a glaucoma specialist consider a trabeculectomy two years after diagnosis when the pressure in both eyes is 18 to 20 mm Hg, and severe inflammation is present?  Are inflammation and the need to get off meds a good reason to progress to trabs?

Dr. Elliot Werner:  If you have moderate to advanced< damage, are intolerant of the meds, and are showing progressive damage, trabs would be indicated.

P:  Isn't intolerance to medications sometimes a reaction to the preservative in meds, rather than the medications themselves?  Shouldn't a patient try preservative-free eyedrops before resorting to cutting surgery?

Dr. Elliot Werner:  Yes, patients who are intolerant of multiple meds are often reacting to the preservative, so it is worth trying preservative-free meds, if the patient can afford them.  They tend to be very pricey.

P:  It's been recommended that I have SLT (selective laser trabeculoplasty).  I've also been told that I have "hardly any" pigment in my trabecular meshwork.  I thought SLT targets only pigment cells. Why, then, would SLT be effective for me?  

Dr. Elliot Werner:  There are studies showing that ALT is more effective in more heavily pigmented eyes.  There are no studies relating success of SLT to the amount of pigment in the trabecular meshwork, so no one knows the answer to your question.

P:  The rates of complications for trabeculectomies are much higher than I expected, but it's sure great to find out beforehand.  I can adjust easier when I'm not surprised.  Thanks!

Dr. Elliot Werner:  Trabeculectomy is a difficult operation for two reasons.  One is that you are making a hole in the eye that you don't want to heal.   From a surgical point of view, and from a physiologic point of view, that is bizarre.  The body does not like to have holes in itself.  It tries very hard to heal them, and if it can't, it often objects. 

The other reason is that almost all other forms of eye surgery are designed to make the patient better, either to see better or to look better. Glaucoma surgery is not designed to make the patient better, just to prevent them from getting worse.

P:  Can eye make-up be worn after a trab? 

Dr. Elliot Werner:  Yes, you can wear eye make-up after a couple of months.  Just be careful putting it on.  Don't poke yourself in the eye.

P:  I have a cup-to-disc ratio of .3 in my right eye and .4 to .5 in the left eye.  My highest intraocular pressure was 20/40 for about 2 weeks.  What would be a target IOP (intraocular pressure) for the left eye?  My IOP before the rise was about 16 and 15 mm Hg.  My visual fields are normal.

Dr. Elliot Werner:  The number 20/40 is a visual acuity number, not an IOP number.

Moderator:  She means the IOP was 20 mm Hg in her right eye and 40 mm Hg in her left eye.  

Dr. Elliot Werner:  It would be an unusual situation to have an IOP of 40 mm Hg in one eye.  I would look for a diagnosis before setting a target pressure. I suspect something else is going on.

P:  Thank you, Dr. Werner.

Dr. Elliot Werner:  Any Canadians here tonight?  

Moderator:  Yes, several, but we usually have more.  They live in New Brunswick in the Maritimes on the east coast, British Columbia on the west coast, and in provinces in between.

Dr. Elliot Werner:  I lived in Canada for 11 years.  Last night I was watching the Daily Show, one of my favorites.  They did a piece on Canadian Conservatives who want to move to the USA now that the Republicans have won the election.  Their comment was, "With its tolerant society, low crime rate, and free medical care, Canada is hell on earth for conservatives."  I enjoyed that.  Hope I didn't offend anyone.

P:  The medical care in Canada isn't free.  It's paid for through taxes.

Dr. Elliot Werner:  You're right, of course, but it is universally available, even if you have to wait for it.  Nothing is perfect.

Moderator:  I'm sorry to hear you are moving.

Dr. Elliot Werner:  But I will be staying in Pennsylvania.  I am joining a practice in Reading, PA, home of great outlet shopping. 

Monitor:  Dr. Werner, I've  always looked forward to your visits.  You've provided so much useful information for patients in the chat room and for those who read the chat highlights online.  I want to thank you and wish you the best of luck.  We're going to miss you.

Dr. Elliot Werner:  I'll be back. Love you all. Have a wonderful holiday season everybody!

End of highlights for December 1, 2004.

On December 8, Dr. Wilson discussed "Glaucoma and Non-glaucoma Medications" in the Chat room. Click here for highlights of that meeting.

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