EyeWorld Asia-Pacific December 2013 Issue

21 EWAP CAtArACt/IOL December 2013 Ivan GOLDBERG, AM, MBBS(Syd), FRANZCO, FRACS GLAUCOMA Clinical Associate Professor, Department of Ophthalmology, Sydney Eye Hospital Director, Eye Associates c/o Eye Associates Floor 4, Park House 187 Macquarie Street, Sydney NSW 2000 Tel. no. +61-2-9231-1833 Fax no. +61-2-9232-3086 eyegoldberg@gmail.com W ith the unpredictability and challenges presented by modern trabeculectomy and glaucoma drainage device surgical procedures, one of the exciting explorations occurring in glaucoma management is that testing the effectiveness and safety of the so-called “Minimally Invasive Glaucoma Surgeries”. While the Glaukos iStent is the one mentioned by Dr. Solomon, there are several available, including the Ivantis Hydrus (Irvine, Calif., USA), Trabectome (NeoMedix Corporation, Tustin, Calif., USA), Gold Microshield, STARflo (iSTAR Medical SA, Isnes, Belgium) and CyPass (Transcend Medical, Menlo Park, Calif., USA). Canaloplasty is often included in this list, but surgical maneuvers are not really “minimal”. Except for Trabectome, all rely on devices (or a suture for canaloplasty) to achieve aqueous drainage either directly into the canal of Schlemm or into the suprachoroidal space. With a variety of levels of evidence available, these devices have demonstrated an intraocular pressure reduction of from 15 - 25% and an apparent enhancement of the observed pressure drop following uneventful phacoemulsification and lens implantation surgery. This enhancement has been reported to include a slightly greater pressure fall for more patients, over a longer time period than noted after cataract surgery on its own and thus to allow for some patients a reduction in the number of anti-glaucoma medications required to maintain target pressures. This data has opened the way for some of these technologies to be accepted by health payers in several jurisdictions (including the United States and Australia) when they are combined with cataract surgery. Necessarily, these devices or procedures involve additional costs, either for the device itself or for non-reusable surgical supplies. Health economics calculations over the next few years will determine the added value of these extra incurred costs. Time will also allow separation between these different approaches: some are likely to be more effective in the longer term for more patients than others, most will prove more appropriate for some patients than for others, some will be shown to be safer than others. But one of the most pleasing aspects of these approaches is the opening of such surgery to comprehensive ophthalmologists performing cataract surgery, because, increasingly, glaucoma surgery as traditionally practiced is contracting into the domain of the glaucoma subspecialist. These approaches promise a surgical technique for glaucoma that would be available much more widely. Time will tell as sensible questions are answered by focused prospective clinical research. Editors’ note: Prof. Goldberg is a consultant for Glaukos and Ivantis but has no financial interests related to his comments. Shamira PERERA, MD Senior Consultant, Singapore National Eye Centre 11 Third Hospital Ave., Singapore 168751 Tel. no. +65-96312157 shamira.perera@snec.com.sg A s the armamentarium of procedures available to the comprehensive cataract surgeon expands, several device companies have targeted them to deliver “add ons” to phacoemulsification surgery for their glaucoma patients. These all concentrate on the irido-corneal angle and are labeled minimally invasive glaucoma surgery or MIGS. The iStent (Glaukos) is one of these and its direct competitors include the Hydrus (Ivantis, Irvine, Calif., USA) intracanalicular implant and the CyPass (Transcend Medical, Menlo Park, Calif., USA). They all have similar obstacles of regulatory approval, patient acceptability and reimbursement to overcome before they see widespread uptake. But despite little being known about the long-term effects of angle surgery, or how many and where best to insert these devices, even glaucoma surgeons will be enticed by the prospect of bleb-free surgeries which do not compromise the conjunctiva for future trabeculectomy surgery. It seems logical that the best option for these MIGS is combined with cataract surgery in terms of patient acceptability and efficacy of IOP lowering. However, needing to insert yet more iStents or performing the procedure without concurrent cataract surgery will understandably be less attractive for patients. Upcoming sustained release glaucoma medications via novel routes of administration and newer angle directed laser procedures also promise less reliance on drops (to improve compliance), yet offer simplicity and flexibility for the patient, too. Hence, in the future, there may be a mix of these modalities working synergistically to stave off trabeculectomy. The main barrier to comprehensive cataract surgeons embracing the iStent is the prerequisite of obtaining good visualization of the angle anatomy, as opposed to learning a technically difficult surgical maneuver. For the Asian eye, where there is a higher incidence of primary angle closure glaucoma and the iStent is contraindicated, its uptake may be more subdued. For these eyes, there may be the option of escalating to cataract surgery and goniosynechiolysis for eyes with significant peripheral anterior synechiae. Alternatively, cataract surgery alone may deliver drop independence for a significant number of medically controlled glaucoma patients where the lens plays a significant part in the pathophysiology. Nevertheless, in the Asia-Pacific region the low risk of complications alone may allure a large number of early adopters to the iStent. Editors’ note: Dr. Perera has received honoraria from Carl Zeiss Meditec (Jena, Germany) and Allergan (Irvine, Calif., USA). Views from Asia-Pacific