Bleb Leaks and Other Complications
Chat Highlights
March 4, 2009

On Wednesday, March 4, 2009, Dr. Elliot Werner, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Bleb Leaks and Other Complications".

Moderator: Welcome back, Dr. Werner. We are glad to have you here. Our topic is Bleb Leaks and Other Complications. First of all, what is a bleb?

Dr. Elliot Werner: Thank you; it's a pleasure. A bleb is the blister-like elevation of the conjucntiva that occurs over the site of the incision after successful glaucoma surgery. The fluid from the eye drains into the bleb and keeps the pressure low.

P: Would that be a trab (trabeculectomy) surgery?

Dr. Elliot Werner: It means any form of glaucoma filtering surgery including trabeculectomy and tube shunt surgery.

P: What is a bleb leak?

P: I am just getting over a bleb leak so am looking forward to this talk.

Dr. Elliot Werner: A bleb leak means there is a hole or defect in the wall of the bleb and the aqueous fluid leaks out into the tear film. The problem with a bleb leak is the eye pressure can go too low (hypotony) and the risk of infection is increased.

P: Where do leaks usually occur? Superiorly, laterally, posteriorly?

Dr. Elliot Werner: In the early phase just after the surgery they typically occur at the site of the incision and sutures. Later on they usually occur in the center, most elevated part of the bleb.

P: What questions should a patient ask if told he/she has a leak?

Dr. Elliot Werner: “What should we do next?” Most bleb leaks are potentially dangerous situations and should not be left alone indefinitely. Some sort of treatment will be indicated depending on the size of the leak, it's postion and the eye pressure level.

P: What is the probability of spontaneous healing?

Dr. Elliot Werner: Very small. Pin point leaks often seal spontaneously; larger leaks rarely seal on their own.

P: Is there a defined course of action?

Dr. Elliot Werner: Usually you start with conservative treatment including topical antibiotic drops, and then stopping steroids if the patient is using them. A large diameter contact lens will sometimes seal the leak. If that fails, some doctors will try to glue the leak. I've never had much success with that. Some doctors will use Diamix to reduce aqueous formation and slow up the leak. Often, if these fail, surgery is necessary to repair the leak.

P: What is the surgery called to repair the leak and how difficult is it?

Dr. Elliot Werner: Usually a bleb revision is done. The thin, leaking portion of the bleb is cut out and a flap or graft of conjunctiva is used to cover the defect.

P: Is this is a difficult surgery, for the patient or the doctor?

Dr. Elliot Werner: It can be difficult depending on the size of the leak and the quality of the conjunctiva. If there is not much scarring and the remaining conjuctiva can be easily mobilized, it's not too difficult. If there is a lot of scarring of the conjuctiva, it can be very challenging. From the patient's point of view, it's not usually more difficult than a trabeculectomy. The procedure is not particularly painful and recovery is similar to a trabeculectomy.

P: If surgery is needed to repair the leak, what is the probability of the bleb filtering effectively again? What are the risks?

Dr. Elliot Werner: There is some risk of failure, but usually if it is a late leak in a well functioning trab, filtration usually continues as before. In early leaks that require the re-suturing of a fresh wound, the increased inflammation can lead to failure. Naturally, there is some risk of failure any time you have to re-operate, but most of the time the procedure is successful.

P: What is the recovery like for bleb leak surgery compared to a trabeculectomy?

Dr. Elliot Werner: It's usually similar. It takes about 6-10 weeks for the sutures to dissolve and the redness and inflammation to settle down.

P: How long passes between the discovery of a leak and surgery?

Dr. Elliot Werner: It depends on the size of the leak and the eye pressure. In small leaks with relatively good IOP, you can wait weeks and try conservative measures. For large leaks with very low IOP or if there is a risk of infection, surgery should be done urgently.

P: How is a bleb leak diagnosed? Are there any signs a patient should be aware of? Can patients feel a leaky bleb?

P: When my bleb started leaking, there was no doubt about it. My eye flooded all night.

Dr. Elliot Werner: Bleb leaks are diagnosed by painting the bleb with fluorescein dye and looking for the leakage of the clear aqueous fluid. They may be asymptomatic or patients may notice a change in vision or increased tearing from the eye is common. They can often feel the leak.

P: If the physical restrictions usually recommended post-trabeculectomy are followed, will it help the healing process of a bleb leak or make no difference?

Dr. Elliot Werner: It will help. It probably doesn't make a lot of difference, but very strenuous activities and straining should be avoided, as should injuries or direct pressure on the eye.

P: Can the use of mitomycin in trab surgery contribute to a leaking bleb “down the road”?

Dr. Elliot Werner: Use of mitomycin is associated with an increased risk of late bleb leaks, but newer surgical techniques seem to have reduced the risk somewhat.

P: How do ointments help with leaks?

Dr. Elliot Werner: Ointments probably don't help much. Some doctors give antibiotic ointments instead of drops, but I don't think the ointment itself makes any difference.

P: If a bleb is going to heal on its own, does it happen within a week or does it usually take longer?

Dr. Elliot Werner: It may take longer, but in my experience leaks don't often heal without the use of something like a large diameter contact lens.

P: How is the treatment different if the bleb leak occurs following surgery or later by trauma?

Dr. Elliot Werner: It probably doesn't. It is the time after surgery, the size of the leak, and the eye pressure level that determine the type of treatment used.

P: How do you know whether there is a risk of infection for a leak?

Dr. Elliot Werner: If you see evidence of inflammation in the bleb or the anterior chamber of the eye, or an increase in discharge or diffuse redness of the eye like a conjunctivitis, then there may be a risk of infection.

P: Some specialists still have some of their younger patients massage the eye. If a leak occurs from massage, once massaging is stopped, is treatment required? Is this leak more difficult to heal?

Dr. Elliot Werner: I don't think the cause of the leak makes much difference unless it is mitomycin. Leaks following mitomycin use after surgery are much less likely to heal without surgery because they are associated with late bleb leaks.

P: Doctor, do you have any take-home message about bleb leaks?

Dr. Elliot Werner: If you have a change in vision, or if your eye feels softer than usual, or if you have increased tearing, or a change in vision, contact your doctor at once.

Now, if you give me a little time, I can tell you about newer techniques to reduce the risk of leaks. A British surgeon named Peng Khaw has developed a new technique for trabeculectomy that results in a much more diffuse, shallow, and thicker-walled bleb. With this technique, w make the incision right at the limbus, where the corneal and sclera come together. We dissect under the conjuctiva very far posteriorly and very broadly. The mitomycin is applied very far posteriorly and the sutures are placed to direct the filtration posteriorly. This newer technique has increased the chance of success and significantly reduced the risk of bleb leaks as well as other complications. Dr. Khaw's work has been a real major contribution.

P: How new are these newer techniques?

Dr. Elliot Werner: They are about five years old.

P: My doctor used a large lens but I still had a small bleb leak which he says is now healed. Does that happen only when they (doesn’t she mean “large” --- as in ) is a very large lens?? I don't understand how the contact lens helps the leak. After it is taken off, won't the leak reform?

Dr. Elliot Werner: Small leaks often heal without surgery. The contact lens probably works like a bandage covering the leak. It also causes a bit of inflammation in the conjuctiva which helps heal the leak.

P: What other complications might a post trabeculectomy patient have?

Dr. Elliot Werner: The pressure might be too low, or too high. There might be infection, hemorrhage, increased cataract, chronic discomfort from too large a bleb, or failure of the trab due to scarring.

P: About how many days after a trabeculectomy can we fly in an airplane?

Dr. Elliot Werner: Nobody really knows, but one week would be safe. There is no evidence that air travel has any effect on a trabeculectomy.

P: Would you use mitomycin in the bleb revision surgery?

Dr. Elliot Werner: No, because you want the conjunctiva to heal and mitomycin prevents healing.

P: Do bleb leaks cause most of trabeculectomy failures if MMC was used?

Dr. Elliot Werner: No. Bleb leaks are actually not a common cause of failure. Most failures are caused by scarring of the sclera and conjunctiva.

P: After a trabeculectomy, is it safe to take over-the-counter cold remedies that a person with glaucoma usually must avoid?

Dr. Elliot Werner: The occasional, limited use of cold medicine is not likely to do any harm. Long-term or chronic use should be avoided.

P: Do you have any advice about swimming in a pool, pond, or ocean with a trab?

Dr. Elliot Werner: Wear good swimmers goggles or a diving mask to keep the water from contacting the eye. Scuba diving should be avoided by patients with trabs.

P: Are drops other than antibiotics used to aid in healing a leak in a bleb?

Dr. Elliot Werner: Sometimes we will use drugs like timolol which will decrease the production of aqueous so that less fluid flows through the leak and may allow it to heal.

P: Generally, how long are trabeculectomies good for maintaining IOP?

Dr. Elliot Werner: It varies a lot, but a good, successful trab can last many years or a lifetime. They do, however, fail, in some patients, as years go by.

P: What is the maximum weight someone can lift after a trabeculectomy and for how much time is the lift restriction necessary?

Dr. Elliot Werner: You shouldn't lift anything that requires straining or is difficult to lift. In an uncomplicated trab, probably about two weeks.

P: Do thin corneas have any bearing on the longevity of a successful trab?

Dr. Elliot Werner: There is no evidence relating the corneal thickness to trab success or failure.

Moderator: That's all the time we have Dr. Werner. It's been a very informative chat. Thank you for joining us.

Dr. Elliot Werner: You're welcome. Good night everyone.

On March 18, Dr. Pro discussed "Punctal Occlusion" in the Chat room. Click here for highlights of that meeting.

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