EyeWorld Asia-Pacific June 2011 Issue

36 June 2011 EW GLAUCOMA aggressive IOP reduction or who have failed medical strategies. If they’re far enough along in their disease, those riskier procedures can be justified.” When post-trab bleb failure occurs, Dr. Mundorf steals a page from the retinal specialists and performs a needle bleb revision with Avastin (bevacizumab, Genentech, South San Francisco, Calif., USA), using the same volume of Avastin as the retinal specialists do (about 1 mg). “Avastin is not as toxic as 5-fluorouracil,” he said. When to initiate laser/surgical treatments Despite all of the advances in glaucoma care over the past two decades, the number of trabeculectomy procedures performed annually has not changed substantially, remaining at approximately 100,000 a year by most estimates, Dr. Singh said. Although the decision to move toward surgery and away from medication is becoming more patient-centric, Dr. Noecker said most of the newer procedures work nicely as adjuncts to cataract surgery. “On the other end of the spectrum are patients who continue to progress. Despite our best efforts, we’re going to hit this group of patients much harder and accept more risk in the surgery,” he said. Across the country, specialists are introducing laser procedures earlier in their management strategy, said Dr. Mundorf, sometimes as early as after the first topical drop stops being effective. Some surgeons have suggested that in prostaglandin responders, the additional IOP reductions offered by SLT are not as impressive as in those non-responders. “ Jorge Alvarado, MD, [professor of ophthalmology, University of California, San Francisco, Calif., USA] first suggested that people who do not respond well to prostaglandins likewise are not going to respond well to laser,” Dr. Mundorf said. “We can always add a laser for a little additional IOP drop, but the bigger drops we tend to expect won’t materialize in that group of patients.” Dr. Cantor suggested clinicians initiate discussion about potential surgery as early on in the process as possible. For the vast majority, beginning management strategies usually involve medications, but for some—those with dementia or Parkinson’s, for instance— beginning treatment with a surgical strategy might be advised. “Those who initially present with advanced glaucoma usually bypass meds and head straight into surgery,” he said. “For the most part, though, one or two bottles of medications are manageable. One could be on a fixed combo, so those two drops might actually be three medications. Once you add in a third bottle, though, it becomes increasingly difficult for the patient and that’s when we’ll typically talk more about lasers and surgery.” Surgical management strategies should differ between phakic and pseudophakic eyes, Dr. Samuelson said. “In a phakic eye, I tend to use minimally invasive measures, whether it’s medication or laser, until the patient develops a visually significant cataract,” he said. “I tend to reserve phaco-trab for far-advanced disease, not for early-to-moderate disease. Once you remove the cataract, the glaucoma is often easier to manage. For pseudophakic eyes, I’m much more willing to perform transscleral procedures. In such cases, if the lens has been removed and medications aren’t controlling the IOP, I am more willing to perform a trabeculectomy than in a phakic eye. Yet, even in pseudophakic eyes, I reserve trabeculectomy for more advanced disease and favor less invasive procedures such as canaloplasty for early to moderate disease.” Dr. Singh—who is on the data and safety monitoring committee for the Tube vs. Trabeculectomy (TVT) Study—said he still generally performs trabeculectomy first in eyes that have had prior temporal phacoemulsification and will often consider a second trabeculectomy in eyes where the first procedure worked for several years and then gradually failed. The results with tube implantation were better than those with trabeculectomy in the TVT Study but “the investigators have at no time published that tube implantation is always the best choice in patients who are pseudophakic or have had prior failed trabeculectomy,” he said. “There are many factors that go into the decision regarding which procedure should be performed in a particular patient, and it is unfortunate that so many have misinterpreted the study results and conclusions. One such misperception is that while the tube study group had a higher success rate, this group required, on average, more medications than the trab group. While this was true at the 1-year post-op time point, there was no difference in the mean number of medications in the two groups at the 3-year post-op time point, and the trend is toward the trab group requiring comparatively greater medications over time. Similarly, the misperception that the trabeculectomy complication rates were higher in the TVT Study relative to those seen in other studies is not supported by the data that shows, for example, that the results with trabeculectomy in TVT compared favorably with those reported in the prior Collaborative Initial Glaucoma Treatment Study.” Despite the study results showing tube superiority, Dr. Singh continues to perform a second trabeculectomy in certain circumstances, especially given his increasing comfort with inferonasal Baerveldt (Abbott Medical Optics, AMO, Santa Ana, Calif., USA) seton implantation over the past decade. In the past, the inferior conjunctiva was not a desirable location for a glaucoma operation, and most surgeons were less likely to try multiple trabeculectomy procedures superiorly with the concern that subsequent tube implantation would be made more difficult due to the scarring associated with prior failed procedures, he said. “The inferior tube option, which is technically not difficult and remarkably well tolerated, gives one more flexibility in performing a second trabeculectomy superiorly in patients where this is the best option for a variety of reasons,” Dr. Singh said. Surgical treatments at status quo “I will once again make the prediction that in 5 years, trabeculectomy, with or without the EX-PRESS, will still be the most commonly performed stand-alone glaucoma surgical procedure,” Dr. Singh said. While he does not believe trabeculectomy will be the most commonly performed combined procedure with cataract surgery in 5 years, he is unwilling to bet on which such combined procedure will emerge as the treatment of choice and said there are presently many promising techniques at various stages. “The ideal profile of such a procedure is ab interno to preserve conjunctiva, preferably performed through a temporal cataract incision and without an adverse impact on visual recovery following cataract surgery,” he said. The reason for these qualifiers, he said, is that as cataract surgery lowers IOP on its own, the addition of significant risk or use of valuable superior conjunctiva with a concomitant glaucoma operation will not be accepted in the overwhelming majority of patients taking IOP-lowering medications who come to cataract surgery. For Dr. Cantor, the more advanced the glaucoma, the “more I lean toward trabeculectomy. The milder it is, the more I’ll perform canaloplasty.” In younger patients especially “you have to take the bleb into consideration, but in really advanced disease, trab is still on average going to give you the greatest odds of getting to lower IOPs.” If (or when) medication therapy is no longer effective, and patients trend toward the higher end of the normal range, “those patients are likely going to have a Trabectome, iStent, or something in the family of less invasive procedures,” Dr. Noecker said. “If patients have pressures in the mid-teens and appear to be progressing,” depending on what additional surgery the eye has undergone, he may try the EX-PRESS, an Ahmed Glaucoma Valve (New World Medical, Rancho Cucamonga, Calif., USA), or Baerveldt tube shunt. He will also use Avastin “for really bad neovascular patients,” although he added they comprise a minority of his patients. Dr. Mundorf’s go-to surgery is New strategies continued from page 35