EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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36 EW FEATURE February 2011 Pseudoexfoliation July 2012 PEX patient with cataract and glaucoma: To combine or not to combine? by Jena Passut EyeWorld Staff Writer AT A GLANCE • For patients who have mild to mod- erate disease, phacoemulsification alone has been shown to reduce pressure • Trabeculectomy, once the "gold standard" for the glaucoma portion of combined surgery, is being eclipsed by less invasive procedures • Risks in combined surgery can be managed by choosing the right procedure for the right patient. In some patients, the risk of vision loss is greater than the periopera- tive risks of trabeculectomy P pupils. Add glaucoma to the mix, and glaucoma-anterior segment surgeons are hit with the unenviable task of deciding whether to perform cataract surgery alone to lower the patient's IOP or attempt a sometimes risky combination procedure. The approval of the iStent Trabecular Micro-Bypass (Glaukos Corp., Laguna Hills, Calif.), the first- ever ab interno implant for the treat- ment of glaucoma, most likely will dramatically change the decision process. (See story, pg. 47.) Until the iStent is rolled out to a mass audience and micro-invasive glaucoma surgery (MIGS) procedures become the norm, EyeWorld asked three surgeons about other ways to approach a PEX patient with co- existing cataract and glaucoma. Traditionally, performing a combination procedure includes phacoemulsification and trabeculec- tomy, but newer, less invasive glaucoma procedures include the ab interno Trabectome (NeoMedix, Tustin, Calif.), a thermal cautery device that ablates the trabecular meshwork and Schlemm's canal through a temporal clear corneal incision, as well as canaloplasty and endoscopic cyclophotocoagulation (ECP). Reay Brown, M.D., glaucoma specialist, Atlanta Ophthalmology Associates, takes the most conserva- tive approach with his PEX patients who have concurrent cataract and glaucoma. With mounting evidence that cataract surgery alone will reduce IOP, Dr. Brown treats pha- coemulsification as an incremental step in treating glaucoma. "I would always try to avoid combined surgery," Dr. Brown said. "There are too many risks, and we have the pressure reduction that we see with cataract surgery alone, which can be profound in eyes that have pressure elevation from glau- coma. There's just something about getting over the cataract surgery and the lens implantation and having the patient recover from the cataract before you move on to something that is, in many ways, anti-cataract." Trabeculectomy, in particular, has opposite goals from phacoemul- sification, Dr. Brown explained. "Instead of having a wound you want to be closed, you have a wound you want to stay open," he said. "You want flow to be coming out of the eye. You don't want to have a sealed eye." Dr. Brown worries that the risks from a trabeculectomy or tubes are too high to attempt most times. "You can redo a glaucoma oper- ation, you can repeat it if it fails, but if you have a serious cataract com- plication, like vitreous loss, zonular dialysis, or cystoid macular edema, sometimes you can not undo the damage," he said. "Patients may have permanent visual loss. Even if you achieve a great pressure, a perfect pressure, they still will have reduced vision forever." Thomas W. Samuelson, M.D., director, Glaucoma Service, and in- structor, ophthalmic pharmacology, Regions Hospital, St. Paul, Minn., and attending surgeon, Minnesota Eye Consultants, Minneapolis, believes phaco alone might not provide enough lowering effect to stabilize patients who have advanced glaucoma. "I look at phaco as an incremen- tal step," Dr. Samuelson said. "If a modest reduction may be enough for a given patient, then phaco alone is a reasonable option. But it simply consumes time, and some patients with end-stage disease don't have the luxury of time or the lux- ury of any disc and visual field re- serve, so in those types of patients you have to do a combined proce- dure because you can't risk progres- sion before the definitive step." Combination procedures have a much better IOP-lowering effect than cataract surgery alone in PEX patients with markedly elevated seudoexfoliation (PEX) syndrome presents chal- lenges to cataract surgery, mainly because of poor zonular support and small pressures or end-stage disease, Dr. Samuelson noted. "For example you may have a patient who has only moderate damage, and if he has cataract and his pressure's 40 mm Hg or more on maximum medical therapy, cataract extraction alone may not be enough, especially if the patient has an open angle," he said. "You would need to do a combined procedure in that setting." Dr. Brown said he worries about the added risk the patient faces during a phacotrabeculectomy. "Without question, the risk is higher, so you have to make sure the patient is at enough risk from the disease to justify that of the proce- dure, and many patients do have enough risk from their disease," Dr. Samuelson said. "They are at risk from going blind imminently. "That is more than just This eye has had a combined phacoemulsification procedure and glaucoma surgery with a bleb and a shunt Source: Reay Brown, M.D. perioperative risk, it's lifelong risk for as long as that bleb remains functional." The risk of hypotony-related complications may be lessened by adding an EX-PRESS Glaucoma Filtration Device (Alcon, Fort Worth, Texas) to the trabeculectomy proce- dure, Dr. Samuelson said. The transcleral procedure offers internal resistance. Adam Reynolds, M.D., in private practice, Boise, Idaho, is more likely to perform a phaco- canaloplasty on older PEX patients who may not be as compliant with their glaucoma medications. "It's a complicated decision," Dr. Reynolds said. "It isn't just the severity of the disease being taken into account; it's the pressure, it's the state of the optic nerve, your assessment of the risk of this patient progressing, the patient's age, the number of medications, and also compliance and adherence issues, the patient's ability to use the drops, and his feelings about the drops. Some patients are adamant that if they can get the (combination) surgery to get them off drops, they are all for it." Dr. Reynolds had to face this very decision the day he spoke to EyeWorld. His patient had a pressure of 30 mm Hg and a 20/50 cataract but had severe disease according to the new visual field criteria.