EyeWorld Asia-Pacific March 2011 Issue

AT A GLANCE • Glaucoma surgeons have a number of new surgical options available including a number of additions and changes within the drainage device market • Modifications continue to be made on traditional drainage devices such as the Ahmed, Baerveldt, and Molteno implants • Surgeons continue to discuss the advantages of the Ex-PRESS implant, which some claim reduces hypotony • Additional options that surgeons expect to see in the US market include the iStent Trabecular Micro-Bypass and the Gold Shunt 14 EW FEATURE March 2011 Investigating glaucoma drainage devices by Vanessa Caceres EyeWorld Contributing Editor The old meets the new in many ways G laucoma surgeons say it’s a great if not dizzying time to work in their field, as surgical options to treat disease abound. “There’s been a boom in the introduction of new shunts recently and new surgical therapies for glaucoma,” said Peter A. Netland, MD, PhD, DuPont Guerry III professor and chair, Department of Ophthalmology, University of Virginia, Charlottesville, Va., USA. “It’s difficult for clinicians to sort their way through all of the information. There are a lot of devices and choices.” Although trabeculectomy is still considered the gold standard for treating glaucoma, a number of drainage devices, both new and old, continue to raise the bar to become the safest and most cost-effective procedure for patients. “The idea is to find something in the future that is 100% safe, effective, and free. That doesn’t exist now, but everyone is trying to get closer to it,” Dr. Netland said. Here’s a look at some of the issues under discussion regarding traditional aqueous drainage devices, how devices such as the Ex-PRESS Glaucoma Filtration Device (Alcon, Forth Worth, Texas, USA/Hünenberg, Switzerland) are changing the market, and what other new technology is on the horizon. Traditional drainage devices Although traditional glaucoma drainage devices may not have the glamour of the new technology, these devices, such as the Ahmed Glaucoma Valve (New World Medical, Rancho Cucamonga, Calif., USA), Baerveldt glaucoma implant (Abbott Medical Optics, AMO, Santa Ana, Calif., USA), and the Molteno implant (Molteno Ophthalmic, Dunedin, New Zealand), continue to thrive. “The whole drainage device concept is explored more now because these traditional devices are well proven,” Dr. Netland said. “Even these traditional devices continue to be modified.” Three-year results from the tube versus trabeculectomy study published last year in the American Journal of Ophthalmology found that in 212 patients—half of whom had a Baerveldt glaucoma implant inserted and half of whom had trabeculectomy performed—showed better clinical results in the tubes (Baerveldt) group. The IOP in the tubes group was a mean of 13 mmHg compared with 13.3 mmHg in the trabeculectomy group; the average number of post-op medications was 1.3 in the tubes group and 1.0 in the trabeculectomy group. Post-op complications were more common in the trabeculectomy group (60%) compared with the tubes group (39%). “While Ideal placement of Ex-PRESS shunt Source: Alcon the incidence of postoperative complications was higher following trabeculectomy [with mitomycin C] relative to tube shunt surgery, most complications were transient and self-limited,” according to the study’s abstract. That study is led by Steven J. Gedde, MD, Bascom Palmer Eye Institute, University of Miami, Fla., USA. Although trabeculectomy is still considered the gold standard for glaucoma treatment, studies such as the tubes versus trabeculectomy have shown that “the pendulum is swinging toward tubes now,” said Leon W. Herndon, MD, associate professor of ophthalmology, Duke Eye Center, Duke University, Durham, NC, USA. One-year results from the ABC—Ahmed versus Baerveldt Comparison Study—were presented at the recent American Academy of Ophthalmology annual meeting’s sub-specialty day, said Douglas J. Rhee, MD, assistant professor, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Mass., USA. Thus far there does not appear to be a big difference in the study between the results from the two devices, but researchers are aiming for at least five-year data, according to the trial description at ClinicalTrials.