Chat Highlights
How To Handle a Failing Trabeculectomy
September 12, 2001

Norma Devine, Editor

On Wednesday, September 12, 2001, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "How To Handle a Failing Trabeculectomy." 

Dr. Rick Wilson:  The topic tonight is "How to Handle a Failing Trabeculectomy." 

P:  Doctor, what symptoms indicate a failing bleb?

Dr. Rick Wilson:  A flattening of the bleb with rising IOP.  That usually happens in the postoperative period, but can happen years later.

P:  What is the most common cause of the failure of a trabeculectomy?

Dr. Rick Wilson:  The most common cause is fibrosis, or scarring of the layer on top of the sclera, closing up the trabeculectomy hole through the wall of the eye.

P:  Many of us have had failed trabs.  Either the bleb is too thin, or the opening made by the trab closed up, and the fluid could not escape.  I had no idea so many things could happen.

P:  I have had two trabs in each eye and various other surgeries.  After needling, both eyes are now stable, but I am nervous about the needling failing.  

Dr. Rick Wilson:  Needling can work for years.  Sometimes it must be repeated.  

P:  I had two trabs by two good doctors and my eye went soft both times.   Do you perform the same trabeculectomy on all patients?  

Dr. Rick Wilson:  Everyone heals differently.  If I did exactly the same trabeculectomy in 100 people, they would all come out differently.  Most people would do fairly well, but some would heal too much and have elevated IOPs again; others would not heal much at all and have unexpectedly low IOPs.  

P:  When can needling be done?

Dr. Rick Wilson:  It can be done at any time if  the bleb is elevated enough to get the needle under the conjunctiva.

P:  What is "needling?"  

Dr. Rick Wilson:  A narrow blade, or needle, is used under the conjunctiva to cut open the scar tissue that's preventing the aqueous from filtering out under a wide area of conjunctiva, to be absorbed by the conjunctival blood vessels and lymphatics.

P:  I've heard that needling is very painful.  Why can't the eye be anesthetized enough to alleviate the pain? 

Dr. Rick Wilson:  It can be done with a small spot of local anesthetic.  I just did one yesterday.  I  used a topical anesthetic, then a very tiny needle with local anesthetic, and the real needling of the bleb was painless.

P:  That sounds encouraging.

P:  I'll have to tell my doctor.  Mine was horrid.

P:  The pain comes after the effect of the anesthetic ends. 

P:  Will they ever come up for a new term, instead of "needling?"  Just the name of it sounds painful. 

Dr. Rick Wilson:  It can be called a  revision of the bleb.  

P:  That sounds better!  So bleb revision and needling are the same thing?

Dr. Rick Wilson:  Yes.  Both act to inhibit scarring of the subconjunctival tissue during the postoperative period.

P:  How can a doctor tell if digital ocular compression (massage) is working?

Dr. Rick Wilson:  The IOP becomes lower and the bleb elevates.  

P:  What is ocular compression?

Dr. Rick Wilson:  Digital ocular compression means using the fingers to press on the front of the cornea to push aqueous fluid through the fistula and keep it open.  The doctor will usually try this in the office to see if it works, then instruct the patient in the technique, and prescribe using the technique a certain number of seconds for a certain number of times a day.

P:  If and when new drugs are developed to open the trabecular meshwork, will someone with a failed trab be able to use them?

Dr. Rick Wilson:  No, the new drugs would not be able to work on the man-made drain, but should work on the blocked natural drain.  The genetic therapy drugs under investigation will work on the trabecular meshwork, encouraging natural filtration of fluid out of the eye.

P:  If trabecular meshwork drugs are perfected, does that mean surgery will not be needed? 

Dr. Rick Wilson:  Trabecular meshwork drugs would work if  there is not a mechanical obstruction to the outflow, like angle-closure glaucoma where the iris is blocking the trabecular meshwork.  

P:  My intraocular pressure is down from 14 to 5 mm Hg.  Does that mean my trab is no longer working?  

Dr. Rick Wilson:  No.  Usually if the IOP is very low it means that the bleb is working too well, or is so thin that aqueous is leaking through it.

P:  What can be done if a bleb is leaking?

Dr. Rick Wilson:  You can wait and see if the leak heals.  Medication can be used to slow down the flow of fluid through the hole.  The hole can be sewed up.  It can be compressed with a contact lens in the hope the leak can be encouraged to heal.  It can be sealed up with blood from the patient.

P:  Why is it so hard to raise IOP surgically in the event of hypotony?

Dr. Rick Wilson:  It is not hard to raise IOP; it's hard to raise it just enough and not too much.

P:  How are retinal folds corrected?  By raising the IOP?

Dr. Rick Wilson:  Yes.  

P:  What is the normal recovery time for a trabeculectomy?  

Dr. Rick Wilson:  Probably two to four weeks of poor vision and two to three months on medication.  

P:  Does the use of laser on the trabecular meshwork render it useless?

Dr. Rick Wilson:  It doesn't seem to.  According to the present theory, the laser helps the cells in the trabecular meshwork clean out the debris in the meshwork.  

P:  Is there a lot of pain associated with a trabeculectomy? 

Dr. Rick Wilson:  Usually there is the feeling of something in the eye, but little real pain.  Many here can answer that question for you, since I have never had one.

P:  I had no pain, but lots of drops!  

P:  I had no pain that Tylenol wouldn't take care of and that was only on the first day.  

P:  I am using Alphagan, Cosopt, Rescula, Pilopine, and Travatan.  My trab is scheduled for two weeks from now.  Will there be additional drops after the surgery?

Dr. Rick Wilson:  There would be only two or three new drops.  You stop the glaucoma medications before surgery.  It is likely that at least two of the medications you are using are not being effective.  It's like beating a dead horse.

P:  How long before a trab would you stop Xalatan?

Dr. Rick Wilson:  Usually two to seven days. 

P:  Hmm, I used Xalatan up to the night before surgery.    

P:  What is the failure rate for a shunt? 

Dr. Rick Wilson:  The failure rate goes up with time.  It starts low at around 10% at six months and increases.  

P:  I have had five surgeries, including a trabeculectomy.  I am on three medications and my IOP today was 35 mm Hg.  What options are there for me?  

Dr. Rick Wilson:  A shunt or shunt revision may be in your future.  Good luck.  

P:  Thank you for all your help.  You make me much more knowledgeable about this disease and what to be aware of.

P:  Dr. Rick, we really appreciate your taking time to come here and answer our questions.  This entire website has been invaluable to me!

Dr. Rick Wilson:  Thanks.  See you next week. Good night everyone. 

End of highlights for September 12, 2001.

On September 17, Dr. Henderer met with the Monday night support group.  Click here for highlights of that meeting.

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