GLAUCOMA EWAP SEPTEMBER 2022 55 similarity in outcomes, he tends to think that the smaller option is safer because it’s taking up less room, it’s less invasive, and there is a lower chance of tube-associated hypotony. One additional reason he likes the 250 ClearPath option is because of patient comfort. When you have to pull on muscles during surgery and put a plate under them, it’s uncomfortable for the patient, and this requires a block, he said. “When you’re not messing with the muscles, you don’t need to do an extensive block, so I’m doing all of my 250 ClearPaths topical without having to block the patient at all, which is safer and more efficient, while still comfortable for the patient.” He added that this may be potentially beneficial if a patient gets double vision and needs to be referred to a strabismus surgeon for muscle surgery, as that surgeon would have access to all muscles if needed. “While I have yet to experience double vision with the 250 ClearPath, in the rare situation the patient has this, the strabismus surgeon has more yeÝibility in fiÝing the problem,” he said. In terms of IOP lowering, Dr. Herndon said that both the Baerveldt and ClearPath can get to similar levels. In multicenter trials with the 350 Baerveldt out to 5 years, the pressures were 14 mmHg, he said, adding that he’s seeing 12–15 mmHg in the ClearPath. For both devices, Dr. Patrianakos said you can get pressures in the low teens, sometimes high single digits, with the larger surface area options. The larger surface area of the 350 may get the pressure down lower, but there are trade-offs too, he said. The larger the surface area of the plate, the more chance of complications, so you have to take that into account. “I do think that the larger the surface area, the lower the intraocular pressure, and when I really want to aim for low pressures, I usually will opt for the 350. It may not be that significant, but it does have some effect,” Dr. Patrianakos said. Dr. Grover said he’s typically seeing pressures in the mid-teens with one IOP-lowering drop. He also mentioned using a diode laser with CPC or ECP. “What’s becoming more of a trend is if a patient has a tube shunt and pressures are not ideally controlled, I can supplement that tube with the low-energy CPC diode, and it allows me to dial down the pressure a bit,” he said. “It’s our responsibility, as a society of glaucoma specialists, any time a new implant comes out, to prove that it’s safe and successful and look at our data. This is what we are currently doing with the ClearPath,” Dr. Grover said. EWAP Reference 1. Grover DS, et al. Clinical outcomes of Ahmed ClearPath implantation in glaucomatous eyes: A novel valveless glaucoma drainage device. J Glaucoma. 2022;31:335–339. Editors’ note: Dr. Grover is an attending surgeon and clinician at Glaucoma Kaijun WANG, MD Professor, Second Affiliated ospital of Zhejiang University School of Medicine No. 1 Xihu Boulevard, Hangzhou, Zhejiang Province, China ze_wkj@zju.edu.cn ASIA-PACIFIC PERSPECTIVES For some refractory glaucoma such as neovascular glaucoma, secondary glaucoma, and other types of glaucoma that fail after multiple filtration surgeries, tube shunt implantation is still the first choice for these patients. The disadvantages and complications of tube shunt implantation include large surgical injury, prolonged recovery, early shallow anterior chamber, and postoperative hypotony. Surgeons and researchers have been devoted to overcoming the shortcomings of these drainage devices and improve its clinical efficacy. ClearPath is a new non-valved draining device, with sizes of 250 mm2 and 350 mm2 options. Theoretically, a draining device with a larger surface area could achieve more sufficient drainage of the aµueous humor and a lower intraocular pressure. However, it is reported that the IOP-lowering effect is similar between 250 and 350 Baerveldt1,2. Due to the larger surface area of the Îx0 Baerveldt, difficulties could be encountered during the implantation procedure. In our hospital, tube shunt implantation is performed under local anesthesia. Isolation of extraocular muscles during surgery could induce discomfort for those patients. A few patients would even develop double vision after surgery due to extraocular muscle disturbance, which was an unacceptable postoperative complication and may need a second surgery. The 250 ClearPath is easier to implant without extraocular muscle isolation, which may achieve smooth surgical procedure and better outcome as well as satisfaction. Therefore, the 250 ClearPath will be more easily accepted by surgeons and patients. The Ahmed glaucoma valve (AGV) is commonly used in China with a surface area of 185 mm2. Application of antimetabolite drugs during and after AGV operation can help to reduce the incidence of drainage tray fiber wrapping and reach a satisfactory IOP-lowering effect. According to practical experience, ClearPath and Baerveldt achieved a similar effect, while ClearPath needs more data to prove its efficacy due to its shorter application duration. Long-term follow-up is necessary to compare between different types of ClearPath and with other drainage devices, in order to provide valuable reference for clinical glaucoma ophthalmologists. References 1. Seah SK, et al. Intermediate-term outcome of Baerveldt glaucoma implants in Asian eyes. Ophthalmology. 2003 May;110(5):888–894. Ó. Allan E , et al. Long-term efficacy of the Baerveldt Óx0 mm2 compared with the Baerveldt 350 mm2 implant. Ophthalmology. 2015 Mar;122(3):486–493. Editors’ note: *rov. 7ang disclosed no relevant financial interests. Associates of Texas Dallas, Texas, and has interests with New World Medical and Nova Eye. Dr. Herndon is Director of the Glaucoma Service, Duke Eye Center, Durham, North Carolina, and has interests with New World Medical. Dr. Patrianakos is Chair of Ophthalmology, Cook County Health, Chicago, Illinois, and disclosed no relevant interests.
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