EyeWorld Asia-Pacific March 2014 Issue

48 EWAP DEVICES March 2014 Diode lasers not just for end-stage treatments by Michelle Dalton EyeWorld Contributing Writer Some glaucoma special- ists believe lasers have a place much earlier in the treatment paradigm T ransscleral cyclophotocoagulation (TCP) applies laser treatment to the ciliary body with an aim of lowering the pressure by decreasing aqueous production. Surgeons have used the 810-nm wavelength in both transscleral and endocyclophotocoagulation (ECP), the latter of which is typically used in combination with cataract surgery to lower IOP and reduce dependence on glaucoma medications. Earlier cyclodestruction methods included cyclectomy, diathermy, ultrasonic energy, and cryotherapy, but the potential side effects—including relatively high rates of hypotony and vision loss— offset the gains in IOP reduction. Although TCP and ECP use the same wavelength laser, and both lower IOP by decreasing ciliary endothelium function, they differ widely in their approach and, to some extent, the types of patients who are best served by each. Some clinicians believe all uses of ciliary ablation are for end stage cases, said Steven R. Sarkisian Jr., MD , glaucoma fellowship director, Dean McGee Eye Institute, and clinical associate professor, University of Oklahoma, Oklahoma City, Okla., U.S. “However, ECP is best performed in early to moderate glaucoma, and TCP is best after other procedures have failed,” such as trabeculectomy filtering surgery or tube surgery. In TCP, the surgeon uses a contact G-probe (Iridex Corp., Mountain View, Calif., U.S.), which Dr. Sarkisian deemed a “game changer” over cyclo-cryoablation because it helped surgeons better target the end-organ tissue. “In terms of effectiveness, a trabeculectomy, a tube shunt, and TCP typically achieve more IOP lowering than ECP, but they also have higher complication rates,” said Parag Parekh, MD , in private practice, Laurel Eye Clinic, Brookville, Pa., U.S. “With ECP, I usually get a moderate effect—somewhere between 0 and 10 mmHg; I average around 5-7 mmHg. ECP is very convenient and safe to do in conjunction with cataract surgery, so phaco-ECP has become my go-to surgery for phakic patients with glaucoma.” Comparing transscleral to ECP Dr. Parekh said with the advent of ECP and other MIGS procedures such as the iStent, he will rarely perform a trabeculectomy as a first line surgical procedure for primary open angle glaucoma, at least not before giving phaco-ECP and/or iStent a chance to be effective. “If it was my own eye, I’d want to give the least invasive procedures a try first,” Dr. Parekh said. ECP is “totally different from transscleral,” Dr. Sarkisian said. “TCP treats the entire ciliary body, Endoscopic cyclophotocoagulation unit showing treated and untreated ciliary body on the monitor Source: Marty Uram, MD