Eyeworld

EW GLAUCOMA 76 October 2016 by Rich Daly EyeWorld Contributing Writer Surgeons see a role for the newer technology, but for now its reach appears limited S urgeons have found a growing role for MicroPulse laser cyclophotocoagu- lation (Iridex, Mountain View, California) among glaucoma patients. But careful tar- geting is key to use of the emerging treatment. Nathan Radcliffe, MD, clinical professor of ophthalmology, New York University Langone Medical Center, New York, has found MicroPulse laser cyclophotocoagu- lation provides clinical benefits in several types of patients among the nearly 200 he has treated with it. Patients who immediately benefit have included those with very severe glaucoma, patients with underperforming tube shunts, and patients for whom it is their first surgical intervention because they are not good candidates for standard glaucoma filtration surgery. With experience, Dr. Radcliffe has expand- ed the therapy to those requiring primary glaucoma surgeries and with moderate glaucoma. Other patients receiving MicroPulse laser cyclophotocoagu- lation, which he can perform in his office, include elderly patients who have trouble using the operating room, such as those without caregiv- ers to take them home. "In my practice I treat a lot of patients who have intraocular tu- mors, and this is my primary thera- py if the patient had a melanoma or other neoplasm," Dr. Radcliffe said. "I treat patients with MicroPulse if they've had a negative experience with traditional glaucoma surgery in the fellow eye," he continued. "You can imagine a variety of scenarios: people who may be on blood thin- ners or people who are at risk for a fall. They're not great candidates for traditional filtration surgery, but a laser surgery is reasonable." Results differ Dr. Radcliffe has found MicroPulse laser cyclophotocoagulation provid- ed significant pressure reductions in many cases. For instance, some pa- tients have had intraocular pressures reduced from 70 mm Hg to 16 mm Hg, which allowed them to get off a number of medications, including acetazolamide. Sometimes the initial treatment did not reduce patient IOPs, but the pressure was reduced after a subse- quent treatment on a higher power setting. "If someone had a 2,000 mW treatment and the pressure came down for a week or two but then came back up, I would offer a sec- ond treatment with 2,250 mW," Dr. Radcliffe said. Dr. Radcliffe tells patients that the treatment does not work for everyone and that it may need to be repeated. "That is actually part of the plan —we're titrating the proper dose," Dr. Radcliffe said. "I think that many surgeons who do not find the thera- py to be effective are not increasing the laser power above 2,000 mW." Conversely, H. George Tanaka, MD, clinical instructor, Department of Ophthalmology, California Pa- cific Medical Center, San Francisco, California, described MicroPulse laser cyclophotocoagulation as only "modestly" effective in his patients. "My failure rate is about 40%, which is more than selective laser trabeculoplasty (SLT)," Dr. Tanaka said. "This is pretty high when you consider you need to take the patient to the OR, have anesthesia present, and give a retrobulbar block." Dr. Tanaka has used the treat- ment in patients who are not good candidates for a trabeculectomy, such as younger patients who have already had SLT and are on maximal tolerated medical therapy. He does not want these younger patients to have a bleb—and the risk of associat- ed complications—for the next 30 to 40 years of their lives. The other group of patients Dr. Tanaka treats with MicroPulse laser cyclophotocoagulation are tradi- tional diode laser cyclophotocoagu- lation candidates—those who have had multiple surgeries, for instance, patients who have a failed trabe- culectomy and one or more failed tubes. Additionally, he will use it in neovascular glaucoma patients with poor visual potential and very high Getting a feel for MicroPulse laser treatment MicroPulse laser cyclophotocoagulation is used to treat a patient who fits its profile. Source: H. George Tanaka, MD Glaucoma editor's corner of the world C yclodestruction is back. The MicroPulse laser is giving surgeons another option for controlling pressure without creating a hole in the eye. MicroPulse joins MIGS in taking a big chunk out of the group of patients who otherwise would have had a trabeculectomy or tube. These safer alternatives have saved many patients from the risks of filtering surgery. H. George Tanaka, MD, and Nathan Radcliffe, MD, discuss their experience with MicroPulse laser in this "Glaucoma ed- itor's corner of the world." Both stress that patient selection is key. They have found this laser treatment useful in patients with complex situations where a trab or tube would have higher risk. These include pa- tients on anticoagulants, older patients, and patients who are post-retinal detachment, silicone oil, or failed glaucoma surgery. Micropulse laser is a less traumatic alternative to external diode cyclophotoco- agulation (CPC) with the G-probe. As with diode CPC, a retrobulbar block is required because of pain—although the treatment takes only minutes to perform. Some sur- geons are performing it in an ASC without a block but giving a short-acting anesthetic like propofol to prevent any discomfort. But the need for an eye block or propofol limits the ability of surgeons to use MicroPulse in the clinic or to titrate the treatments or perform subsequent treatments. Cyclodestruction continues to be an appealing treatment option. It takes so many of the dreaded complications of glaucoma surgery—endophthalmitis, bleb leaks, flat chambers, malignant glaucoma —right off the table. But the treatment is very indirect—applying laser energy to the ciliary body through the sclera. So we can't see where we are treating or visualize the effect of the laser. This makes the level of pressure-lowering uncertain. There will be great successes but also more failures than we would like. Perhaps this reflects the early stages of this treatment modality, and better parameters will be worked out as more surgeons start using MicroPulse. Reay Brown, MD, Glaucoma editor

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