EyeWorld Asia-Pacific June 2011 Issue

35 June 2011 EW GLAUCOMA Avascular, leaking area of bleb margin is incised and a posterior conjunctival flap is raised After posterior conjunctival flap is undermined and bleb surface is cauter- ized, the flap is draped over the bleb and sutured to the limbus Source: Iqbal (Ike) K. Ahmed, MD of ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Ind., USA: “There’s only so much manipulation you can do with a bleb-based procedure. The EX- PRESS can standardize one step in the surgery, but I haven’t seen the need to assume the additional expense for the most part. I think we’re hitting a technological wall with filtering surgery. The interest is in how we can surgically control glaucoma without creating a bleb. A bleb is just a ticking time bomb.” When it comes to glaucoma surgery, “it’s been a slow, arduous process to put new procedures in the hands of surgeons,” said Thomas W. Samuelson, MD, director, glaucoma service, and instructor, ophthalmic pharmacology, Regions Hospital, St. Paul, Minn., USA, and attending surgeon, Minnesota Eye Consultants, Minneapolis, Minn., USA. He cited a patient he had just seen who had undergone trabeculectomy a few years earlier—“utilizing all the new techniques to obtain a more favorable bleb morphology”—yet the patient still presented with a bleb-related infection. “It underscores the risk of filtering blebs and how they’re vulnerable to infection even years after the original surgery,” he said. “As a group, we have to be looking for a better way. We simply can’t be satisfied with a procedure that leaves the patient at risk for a devastating event, such as bleb- related endophthalmitis, for the rest of his life.” Some surgeons have “not significantly changed glaucoma practice patterns over the past 5 years,” said Kuldev Singh, MD, professor of ophthalmology and director, glaucoma service, Stanford University School of Medicine, Stanford, Calif., USA. Other than performing modern cataract surgery earlier as a means of offering better visual acuity as well as IOP lowering/reduction in glaucoma medications in patients with mild and/or well-controlled disease, his practice patterns have not changed much in recent years. The “big breakthrough in glaucoma surgery” has yet to come, Dr. Singh believes. “There are more than 3 million cataract procedures performed each year in the United States, and an estimated 15% of these are on patients who are receiving IOP- lowering medications for glaucoma or ocular hypertension at the time of such surgery,” he said. “Cataract surgery lowers IOP, although the effect is variable, and there is generally little—if any—downside of early cataract surgery in patients who also have visual disturbances related to lens opacification.” Another reason Dr. Singh considers performing cataract surgery as a means to both improve vision and better control IOP is that “temporal clear corneal phacoemulsification does not negatively interfere with future glaucoma surgery.” A “significant proportion of patients with mild glaucoma or ocular hypertension are able to reduce or eliminate the need for glaucoma medications following modern cataract surgery, and even when this does not occur, cataract surgery rarely makes glaucoma more difficult to manage post- operatively in such patients with mild disease,” Dr. Singh said. A good majority of patients “don’t understand the implications of surgery”, Dr. Cantor said. “It’s crucial to have the conversation with them as early on as possible. We need to tell patients that although surgical procedures have improved, they’re not perfect and there is no cure. With trabeculectomy, there’s an 80–90% success rate at year one, but over subsequent years there’s a 5% risk of failure. After 10 years or so, you’ve got a 50% chance that surgery is still working.” Dr. Cantor advises surgeons to tell patients that “surgery is designed to stop vision loss from becoming worse. You need to tell them they’re not going to see ‘better,’ they’re just not going to get worse as quickly as they would without the surgery.” For those with pseudoexfoliative glaucoma and cataract, early phacoemulsification can be supported for an additional reason; removing a moderately opacified lens “will require less energy and is presumably safer than waiting for the lens to become very dense in this high- risk group,” Dr. Singh said. He believes that trabeculectomy, with or without the EX-PRESS, will continue to be the predominant stand-alone procedure for patients with severe and/or uncontrolled glaucoma in the coming years. He said the initial breakthrough in glaucoma surgery will be “a cataract plus glaucoma operation that is performed at the time of phacoemulsification in patients with mild-to-moderate glaucomatous disease who are undergoing surgery predominantly for visual impairment related to cataract and also happen to be under treatment for glaucoma. Phacotrabeculectomy will be replaced by phaco-something else as the most frequently performed cataract-glaucoma combined procedure over the next 5 years,” he said. “If a blebless combined cataract and glaucoma procedure can, on average, safely lower IOP at least 2–3 mm Hg more than cataract surgery alone over the long term, such a breakthrough will have significant public health implications,” Dr. Singh continued. “As cataract surgery continues to be performed sooner and life expectancy increases in successive generations, a safe, combined cataract-glaucoma procedure that allows patients to reduce their subsequent dependence on glaucoma medications and need for further surgical intervention will not only result in decreased morbidity but also significant cost savings for future generations of glaucoma patients.” For Dr. Noecker, the big question remains how effective non-penetrating surgery will be over the long term and how it will affect the number of trabeculectomy surgeries performed yearly. “There’s a growing trend here— we’re decreasing the gap between office-based surgery and making the jump to the [operating room],” Dr. Noecker said. Newer procedures offer less risk for the patient, he said. Endolaser cyclophotocoagulation (ECP) has shown increased acceptance, although the procedure has yet to be universally accepted, Dr. Samuelson said. Proponents of the procedure cite better titration of the laser energy when delivered endoscopically as compared to transscleral laser procedures. “Surgery as a whole is moving toward more blebless procedures,” he said. “ECP may be a good adjunct to modify the inflow side of the equation to the blebless procedures that work on the outflow side.” In his opinion, one of the benefits of the newer blebless procedures is retention of the physiologic pathway; these include the Trabectome (NeoMedix, Tustin, Calif., USA) and the iStent (Glaukos, Laguna Hills, Calif., USA). Dr. Cantor has been pleased with his outcomes with canaloplasty procedures. He, too, is awaiting the US approval of the iStent. “I don’t think either of those procedures will replace trab or tube shunts,” he said. “Glaucoma surgery needs different procedures for different patients, and we’re now at a point where we do have good options beyond a one-size- fits-all mentality.” “Trab and tube shunts still play an important role in glaucoma management,” Dr. Samuelson said. “We see patients all the time who don’t come in until late in the disease progression who need continued on page 36