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November 2012 Cataract/glaucoma combined surgeries February 2011 EW FEATURE 45 there is no bleb like in trabeculec- tomy that can leak or get infected," Dr. Loewen said. The main downside, he finds, is that it may not work as well in low pressure glaucoma. Another draw- back is that this is not an easy procedure to learn. Many traditional trabeculectomy surgeons think in terms of punching a hole and stitch- ing it shut. "If you have that mind- set for the Trabectome, it's not going to work," Dr. Loewen said. "You have to be extremely careful not to damage the outer wall of Schlemm's canal that contains the intake orifices of the drainage system." While there are fewer complica- tions with the ab interno approach, it is not complication free, Dr. Rhee stressed. "You can make a mistake and hurt someone very badly with this if you create a cyclodialysis cleft," he said. In such cases, pressures go very low. Still, as far as Dr. Loewen is con- The ab interno Trabectome approach opens up communication between the anterior chamber and collecting channels Source (all): NeoMedix than trabeculectomy," Dr. Rhee said. With this approach the practitioner ablates the trabecular meshwork and the inner wall of Schlemm's canal for anywhere between 60 and 140 degrees using the Trabectome. "That provides direct communication between the anterior chamber and collecting channels," Dr. Rhee said. Nils A. Loewen, M.D.,Ph.D., assistant professor of ophthalmol- ogy, University of Pittsburgh School of Medicine, Pittsburgh, sees the speed of the approach as highly advantageous. Also, he pointed out, it does not induce noticeable astigmatism. "If you had a (pre-op) astigmatism of 2 D, you can very nicely put in a lens that corrects this and not be sur- prised by unpredictable surgery- induced astigmatism," Dr. Loewen said. By contrast, trabeculectomy and canaloplasty can occasionally induce more than 3 D of astigma- tism, he finds. In the long term, with ab interno trabeculectomy using the Trabectome there are no infections to be wary of. "There's no hardware that erodes through the eye, and cerned, ab interno trabeculectomy is certainly part of the minimally inva- sive glaucoma surgery (MIGS) treat- ment contingent. "This requires just a small incision and removes a tiny structure that's only several microme- ters thick," Dr. Loewen said. "This is a classic minimally invasive surgery, as is ECP and the iStent [Glaukos Corp., Laguna Hills, Calif.]." For his part, Dr. Rhee prefers the term "non-full thickness" procedure to MIGS here. "I think that it's more accurate," he said, pointing out that a treatment such as canaloplasty, considered by some to be part of this group, is invasive. However, Dr. Berke views ECP as "the original MIGS" with a better safety profile than trabeculectomy and tube shunts, but without as much pressure-lowering punch. While he has not yet used the newly FDA-approved iStent, also embraced as a MIGS, he is already thinking ahead to minimally invasive proce- dures in the future. "I believe that ultimately someone will try using both ECP and either the Trabectome or the iStent together to see if they are more effective at lowering IOP," Dr. Berke said. "In this case, we may be able to combine two MIGS proce- dures and achieve what we want to, which is pressures that are closer to what we can achieve with a tra- beculectomy without having to do a trabeculectomy." EW Editors' note: Drs. Berke and Rhee have no financial interests related to this article. Dr. Loewen has no current financial interests related to this article but was a consultant to NeoMedix through the spring of 2012. Contact information Berke: 516-593-7709, sberke@ocli.net Loewen: 412-944-2554, loewenna@upmc.edu Rhee: 617-573-3670, dougrhee@aol.com Ophthalmic Women Leaders