Eyeworld

NOV 2014

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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51 EW FEATURE Risks remain Despite changes in the use of phaco- trab, it retains all of the same risks found in standalone trabeculectomy, including bleb leak, hypotony, and choroidals. In addition, the com- bined procedure has the unique risk of unpredictable refractive out- comes. In an era of cataract surgery that reliably produces vision within 0.5 D of plano, post-combined pha- co-trab vision is harder to predict given the anticipated axial length shift, as well as the induction of astigmatism. The more complicated nature of the traditional combined procedure requires surgeons to spend some time counseling patients regarding refractive out- comes and managing expectations. "This is not to say that we don't do a pretty good job at minimizing the final prescription in patients undergoing phaco-trabs, it is just that there is definitely a higher degree of unpredictability," Dr. Kammer said. EW Editors' note: Dr. Devgan has financial interests with Alcon. Dr. Kammer has no financial interests related to his comments. Contact information Kammer: jeffrey.kammer@vanderbilt.edu Devgan: devgan@ucla.edu at the same time as cataract surgery to help further control the IOP." However, when a larger IOP re- duction is needed than cataract sur- gery alone can provide, Dr. Devgan still uses the phaco-trab procedure. Other factors that could spur the use of a combined procedure include the presence of systemic health issues that make anesthesia riskier. Dr. Kammer typically considers traditional combined surgery in cataract patients with poorly con- trolled IOP on multiple medications, controlled IOP but a poorly tolerated medical regimen, significant medica- tion-induced hyperemia, advanced glaucomatous damage, and in those who require minimizing the anesthetic risk posed by multiple surgeries. Tool and technique changes Among the recent changes in the traditional combined procedure added by Dr. Kammer are preop in- jections of mitomycin-C (MMC) in a subconjunctival fashion 90 degrees away from his intended incision site. "I subsequently massage the medication toward the proposed incision location and then let it sit there for 5 to 10 minutes," Dr. Kammer said. "This allows for a more even distribution of the mitomycin and promotes the formation of a low, diffuse bleb." The result is better-tolerated blebs that rarely become ischemic or leak. Creation of the fornix-based flap includes irrigating the excess fluid out with balanced salt solution to minimize the risk of seepage of any residual MMC into the anterior chamber. "To date, I have not had any episodes of corneal decompensation associated with the preoperative injection of mitomycin," Dr. Kammer said. Dr. Kammer has also adjusted the order in which he performs phaco-trabs. After occasionally struggling with burping the phaco incision when pulling down on the traction suture to get expo- sure, he moved away from cataract extraction followed by traditional glaucoma surgery. This issue was especially likely to arise in patients with small eyes and tight orbits. Dr. Kammer moved to first performing the peritomy and scleral flap dissec- tion, which is much easier with an intact globe, in patients with small eyes. That step is followed by the cataract extraction and then comple- tion of the glaucoma surgery. "This requires moving the microscope one more time, thus adding 20–30 seconds onto the case, but often saves time by making exposure easier," Dr. Kammer said. The primary change in the way that Dr. Devgan performs the traditional combined procedure relates to the choice of 1 operative site versus 2. His previous use of a superior scleral incision for both the cataract surgery and the trabe- culectomy has transitioned to the use of 2 separate sites. A temporal corneo-limbal incision is created for the cataract surgery, followed by a superior scleral incision for the trabeculectomy. Use of adjuncts, like the EX-PRESS Glaucoma Filtration Device (Alcon, Fort Worth, Texas), varies among surgeons. Dr. Devgan has seen its use in combined procedures generally relegated to resident surgical cases because it provides them a more consistent aperture size and outflow. Casual glaucoma surgeons also may benefit from the reproducibility that the device provides, Dr. Kammer said. Costs limit Dr. Kammer's use of the EX-PRESS device to several procedures, such as phaco-trabs, due to the faster recovery it allows. He has also found the device reduces inflammation in uveitics, minimizes bleeding in resolving neovascular glaucoma patients, and provides slightly less hypotony-related complications in high myopes. "I use it selectively in other patients depending on their risk profile and other comorbidities," Dr. Kammer said. "As we approach an era where we are going to be scruti- nized for the resources that we use, it's important to consider cost in the decision-making process." EyeWorld Monthly Pulse EyeWorld Monthly Pulse is a reader survey on trends and patterns for the practicing ophthalmologist. Each month we send an online survey covering different topics so our readers can see how they compare to our survey. If you would like to join the hundreds of physicians who take a minute a month to share their views, please send us an email and we will add your name. Email carly@eyeworld.org and put EW Pulse in the subject line. Poll size: 116 November 2014 Combined procedures for glaucoma

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