Time for Trabeculectomy?

Question: What’s the latest thinking on whento send a glaucoma patient for filtering trabeculectomy surgery?

Answer: Many doctors don’t want to burden the patient with too many medications, increasing the chance of side effects and decreasing the likely compliance. They opt instead for more aggressive surgical intervention.

“If patients don’t achieve an appropriate target pressure with two topically applied medications, then they are good candidates for further intervention,”says Christopher J. Quinn, O.D., of Omni Eye Services in Iselin, N.J.

Many doctors consider argon laser trabeculoplasty (ALT) as an adjunctive treatment to medication for patients with mild to moderate glaucoma. If that too doesn’t achieve target IOP, the next step is to refer the patient for surgical trabeculectomy.

“The big advantage of surgery … is that we often are able to achieve much lower pressure than we are able to get with medications, or medications and ALT alone,” Dr. Quinn says. “And of course in most patients we eliminate the need to use most topical medications following surgery.”

Question: What’s the trend in antimetabolite therapy for filtering trabeculectomy?

Answer: Mitomycin-C is the antimetaboliteof choice, says Douglas Grayson, M.D., also of Omni Eye. Applied to the incision during the procedure, it’s effective in preventing scar tissue from forming and increases the success rate of the filtering bleb. (Sometimes it works too well, causing a leaky bleb that drops the pressure too low. In such a case, watch for low pressure and a decrease in vision during the post-op management. Use a Seidel’s test to check for excessive aqueous leakage.)

Compared to Mitomycin-C, surgeons use injections of 5-fluorouricil (5-FU) less frequently these days as antimetabolite therapy.

Question: What’s the optometrist’s role inthe postoperative care for the surgical trabeculectomy patient?

Answer: Expect to be more involved than you would with a cataract patient. Not only will you need to watch the patient more carefully, but you’ll also need to communicate with the referring glaucoma specialist more closely.

In the initial 3-4 weeks post-op, the surgeon sees the patient for laser suture lysis and follow-up. When the patient comes to your office, yourjob is to monitor the pressure and assess the efficiency of the filtering bleb, Dr. Quinn says.

“Any time a patient comes in who’s had a filtering trabeculectomy, routinely check for a leak with a fluorescein strip,” Dr. Grayson says.
If IOP is too high, consider adjunctive glaucoma medication or refer for a transconjunctival needle revision procedure to break up the scar tissue, Dr. Grayson says.

Besides checking for adequate IOP, observe the appearance of the filtering bleb. It should be elevated and avascular.

You must also watch out for infection. It can occur at any time from weeks to years after the surgery. Bleb infections have a very high riskof developing endophthalmitis, so take all calls about a red eye very seriously,even if it seems like simple viral conjunctivitis. Prescribe an antibiotic prophylactically, Dr. Grayson says.

If there is intraocular inflammation, he adds, start the patient on an aggressive regimen: Ciloxan (ciprofloxacin) or Ocuflox (ofloxacin) everyhour, and follow up in 24 hours. Keep the patient on antibiotics at least a week until the signs of infection have subsided. If there is hypopyon, promptly refer the patient for intravitreal antibiotic injection.
Another reason to monitor pressure: Patients who have a leaky bleb have increased risk for infection, Dr. Quinn says.

Optometrists have to be comfortable with the aggressive use of steroids for these patients, he adds. Typically, the patient is on Pred Forte (prednisolone acetate) every 2 hours for several weeks and up to 4 times a day for 8-12 weeks following the procedure.

You’ll still need to follow the patient for glaucoma. Perform visual fields, monitor for visual changes, observe the macula, and generally try to maintain the eye’s status quo, Dr. Grayson says.

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Dr. Paul C. Ajamian
c/o Review of Optometry
11 Campus Blvd., Suite 100
Newtown Square, PA 19073
Attn.: CMQA
Or fax it to 610-492-1039, or e-mail it to reviewofoptometry@jobson.com.

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