Trabeculectomy, the First Three Months
Chat Highlights
November 5, 2008

On Wednesday, November 5, 2008, Dr. Michael Pro, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Trabeculectomy, the First Three Months".

Moderator: Tonight's topic is "Trabeculectomy, the First Three Months”. Do you have some opening remarks Dr.Pro?

Dr. Pro: Well suffice it to say that the Trabeculectomy (Trab) remains the number one glaucoma incisional (surgical) procedure and is thus very relevant for patients to understand.

P: What are normal feelings in the eye after a trab in the first few days, week, and six week periods? What could cause sensations?

Dr. Pro: In the first few days it is common to feel a foreign body sensation, due to sutures. There are numerous ways to do a trab, and different surgeons use different types of sutures, but it is still common to get a scratchy sensation in the first few days. After a week or so these sensations can resolve, either with suture removal or eventual dissolving, or as the eye heals over sutures which are flush to the surface of the cornea.

But other sensations can happen; the vision can be blurred, either due to tight corneal or scleral sutures, blood in the eye, or a (usually transient) low pressure. By one month the vision is usually better and back to baseline, and most of these minor sensations have resolved.
The above sensations are normal, but it is not normal to have severe pain, severe loss of vision, or sudden change in vision.

P: What happens to the IOP immediately following surgery?

Dr. Pro: Great question; let me first describe a trab. Basically a trab is the creation of an artificial drain, which bypasses the normal aqueous drainage, and shunts aqueous from the eye to a space underneath the conjunctiva, right over the cornea and covered by the upper lid. Unfortunately, the success of the surgery is very dependent on the healing rate of any particular patient. So scarring around or over the scleral flap (which is part of the artificial drain) can lead to failure of the surgery.

So back to the question, immediately after surgery the pressure is usually lower than prior to surgery, but not always. The flap is secured by several sutures, this is necessary to prevent uncontrolled egress of aqueous which can lead to a dangerously low intraocular pressure (IOP). If these sutures are tight, then the post-op pressure at day one can be high.

P: Dr.Pro, will the trab,cause a thinning of the cornea in any way?

Dr. Pro: A trab can cause corneal thinning if a dry patch develops under an elevated bleb (the pocket of fluid underneath the conjunctiva covered by the upper lid).

P: Can IOP being too low cause any problems?

Dr. Pro: A too low IOP can cause blurry vision, because the retina can become wrinkled.

P: Would drops be necessary after the trab surgery?

Dr. Pro: Yes, drops are commonly needed after a trab, if the IOP is still not low enough.

P: How many trabeculectomies can be done on the same eye?

Dr. Pro: There is really no set number of trabs that can be done to an eye, but it is very tough to do more than three, due to scarring of the conjunctiva from previous surgeries.

P: What activities are restricted after surgery and for how long?

Dr. Pro: For the first week I restrict my patients to a minimum of strenuous physical activities. They should not lift heavy objects (a gallon of milk) over the head and they should not pick up a heavy object from the floor. No sports, no swimming. they my shower, but are to avoid rubbing the eye. Over the next several weeks usual activities are gradually restarted, and by one month most patients can enjoy their usual activities. I would add that at no time are patients restricted from flying.

P: How long should a patient wait before they sneeze and cough?

Dr. Pro: Again it is best to avoid forceful sneezing and coughing for one week. Sometimes that means using a cough suppressant after the surgery if a patient develops a cold.

P: If you can't rub the eye, what is the best way to scratch an itchy eye after surgery?

Dr. Pro: Best to apply a lubricant drop into the eye and if you need to wipe, be sure to use a tissue on the lower lid. Do not press into the eye, but on the lower orbital ridge (the bone of the orbit).

P: Due to prior surgeries, I can only wear contact lenses for correction. Is there a type of lens that works after a trab?

Dr. Pro: Usually wearing contact lenses is contraindicated after a trab because contact lens use can increase your risk for an infection. I know of no contact lens that is better than any other.

P: When do most patients return to work?

Dr. Pro: They can usually go back to work within several days of surgery. Sometimes my patients take off the remainder of a week and resume work the next Monday. Some patients have especially dirty or physical jobs, and they can be out of work for several weeks to a month (only in extreme cases).

P: What is the eye drop regime during the first six weeks post surgery? Any drops from six weeks to three months?

Dr. Pro: First week I have my patients use an antibiotic, a steroid, and usually an anti-inflammatory. After a week the antibiotic is stopped. The steroid and anti-inflammatory drops continue for one month. I then will stop the anti-inflammatory and taper the steroid over the next month.

P: How and why is 5FU used post surgery?

Dr. Pro: 5FU 5-flurouracil) is an anti-metabolite used at the time of surgery to prevent scarring. MMC (mitomycin C) is a chemotherapeutic perhaps more commonly used today for the same purpose.

P: Does the steroid drop prescribed after surgery cause the pressure in both eyes to increase?

Dr. Pro: Not usually. Since an artificial drain is created in the surgical eye, it is largely protected from a steroid IOP response. It is very rare to get a steroid induced IOP elevation in a non-treated fellow eye. And, finall,y the drops are used for a limited time.

P: Post-trab, is there a benefit to sleeping propped up in bed?

Dr. Pro: I do not have my patients sleep propped up. I think it is also important for normal healing for patients to get a good rest so I do have my patients wear a clear plastic shield over the eye during sleep for at least a week.

P: Dr Pro, after a trab, what statements should I listen for during a bleb exam from my physician?

Dr. Pro: Bleb height, width, vascularity, and presence of any leaking. A bleb that demonstrates increasing vascularity is in danger of failing.

P: What problems would prompt an immediate call to the surgeon?

Dr. Pro: Like I mentioned earlier, loss of vision or worsening of vision or pain is a reason to call.

P: Thank you, Dr. Pro. Your explanations and answers have been most helpful. As I prepare for my surgery, I continue to learn more about what I can expect and that keeps me feeling that I have a little control over this seemingly uncontrollable situation.

Moderator: Dr. Pro, it is half-past the hour. Thank you for your time. Have a great week.

Dr. Pro: Thank you, and good night.

On November 19, Dr. Wilson discussed "Shunts, The First Three Months" in the Chat room. Click here for highlights of that meeting.

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