GLAUCOMA EWAP SEPTEMBER 2023 43 said. “Whenever you see a lot of pigment in the angle, you’re more likely to get a good pressure drop if you remove the tissue because you know that’s where the problem is. There are other diseases where some patients may have a congenital abnormality of the trabecular meshwork. … On gonioscopy you look at the angle and you see the angle is abnormal. In those cases, we excise the tissue, and we find the outflow works well. Juvenile ones would often respond well to trabecular removal as well.” Surgically, Dr. Harasymowycz said there are different instruments that can perform goniotomy. Even a bent 27-gauge needle can be used, which he said is a money saver. Dr. Gooi also said it is cost effective to perform a goniotomy with a 5-0 polypropylene suture. One of the cons of the procedure, Dr. Gooi said, is the potential for postoperative hyphema, especially if a more than 180-degree goniotomy is performed. He also said that it doesn’t treat outflow pathways outside of the trabecular meshwork. Canaloplasty Dr. Harasymowycz said there is still traditional canaloplasty, which is performed ab externo, but it’s more common now to do ab interno canaloplasty Visanee Tantisevi, MD Associate Professor, Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University 1873, King Chulalongkorn Memorial Hospital, Rama 4 Rd., Patumwan District, Bangkok, Thailand tvisanee@gmail.com ASIA-PACIFIC PERSPECTIVES C anal-based surgeries such as goniotomy, GATT, or ABiC for open-angle glaucoma has advantages over trabeculectomy in many aspects, in particular the lack of risk of surgical bleb complications as they are bleb - less procedures. The most appropriate patients to receive these surgeries whether as sole procedure or combined with phacoemulsification are those whose postoperative IOP is targeted at the mid-teens. Visible angle and trabecular meshwork are the key since the procedures are directed towards elimination of resistance between the anterior chamber and Schlemm’s canal as in goniotomy or to reconstitute patency of the presumedly collapsed Schlemm’s canal. 1 Goniotomy has also been advocated for its bleb-less character in angle-closure glaucoma treatment. A recent multicenter observational study showed good results over 12 months follow-up in advanced glaucoma with cataract patients; however, the procedure applied was combined phaco/goniosynechialysis/goniotomy. Goniosynechialysis was necessary to open the angle 120 degrees to employ the goniotomy with bent needle. Nonetheless, longer-term outcomes and comparison studies are warranted. 2 Apart from some difficulties in technique and the most debatable issue of IOP outcomes, to ensure safety during canal-based surgery such as canaloplasty, a catheter with beacon is recommended for assistance during the canal insertion. This makes the procedures less used in practice in many Asian countries where advanced glaucoma is addressed and cost-effectiveness is to be considered. Instead of using a beacon, a 360-degree trabeculotomy with specific suture was introduced with satisfactory effectiveness in treating POAG or pseudoexfoliation cases. Again, these sutures are not commercially available in most regions, resulting in surgeons who need to perform the procedure developing their own techniques that resemble this kind of surgery. 3 In addition, for PACS, PAC, early or moderate PACG, cataract removal only or occasionally with goniosynechialysis are proven adequately effective in longer-term IOP control. Subconjunctival stents such as ExPress, Xen, or Preserflo are more attractive to a considerable number of surgeons due to their IOP lowering efficacy and ease of use, despite the fact that they are bleb-forming procedures and bleb complications can be encountered. In addition, better understanding of bleb management makes the surgical blebs seem less of a problem and surgeons are less afraid of serious complications. Despite the abovementioned, because of the variety and newer evolving techniques for canal-based procedures and bleb-less surgery, this type of operation benefits from avoiding bleb complications with possible fewer postoperative visits. Therefore, it still has lots of potential to be realized. References 1. Gallardo MJ, et al. Viscodilation of Schlemm’s canal for the reduction of IOP via an ab-interno approach. Clin Ophthalmol. 2018 Oct 23;12:2149-2155. doi: 10.2147/OPTH.S177597. PMID: 30425450; PMCID: PMC6205145. 2) Song Y, et al.; PVP Study Group. One-Year Results of a Multicenter Study: Intraocular Pressure-Lowering Effect of Combined Phacoemulsification, Goniosynechialysis, and Goniotomy for Cases of Advanced Primary Angle-Closure Glaucoma With Cataract. Asia Pac J Ophthalmol (Phila). 2022 Nov 1;11(6):529-535. doi: 10.1097/APO.0000000000000579. PMID: 36417677. 3) Tanito M, Matsuo M. Ab-interno trabeculotomy-related glaucoma surgeries. Taiwan J Ophthalmol. 2019 Apr-Jun; 9(2):67-71. doi: 10.4103/tjo.tjo_38_19. PMID: 31198665; PMCID: PMC6557068. Editors’ note: Dr. Visanee Tantisevi declared no relevant financial interests related to the products mentioned in her comments. continued on page 49
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