Glaucoma Surgery

•There are 3 main approaches to glaucoma surgery: subconjunctival, Schlemm canal–based, and suprachoroidal/ciliary body.•Subconjunctival surgery is ideal for patients with advanced disease, low target pressures, prior failed surgery.•Although transscleral cyclophotocoagulation has classically been reserved refractory glaucoma, micropulse technology might become an indispensable tool used earlier during the disease process, sparing higher frequency of serious complications older technology.•Although canal–based procedures usually considered in mild moderate cases controlled or slightly above-target intraocular pressure often combined cataract surgery, suprachoroidal shunts still struggling find their role currently undergoing further trials validate efficacy safety.•Preliminary evidence implies a possible some newer microinvasive treating incisional surgery. The field going through era renaissance last 2 decades, quickly expanding armamentarium new innovative surgical options adding classic filtration Trabeculectomy generally gold-standard treatment one most effective procedures, although that associated complications, making many surgeons reconsider its paradigm. Nonpenetrating (NPGS) enhanced versions, such as canaloplasty, also were developed, aiming increase safety profile, sometimes at expense less efficacy. Tube have implemented both after surgeries complex secondary cases, which carry risk failure trabeculectomy. Cyclodestructive mainly very visual potential. introduction laser reshaped way think these types them more attractive perform stage good term (MIGS) was coined 2012 describe ab interno procedure, minimal trauma, efficacy, high rapid recovery [[1]Saheb H. Ahmed I.I. Micro-invasive current perspectives future directions.Curr Opin Ophthalmol. 2012; 23: 96-104Crossref PubMed Scopus (304) Google Scholar]. As thought be superior interventional suggested infer intervention done process. Many introduced since then, while grouped under umbrella MIGS, differ may by externo approach, XEN gel stent Preserflo microshunt. It prudent, however, classify glaucoma-surgical according site treatment, namely canal, ciliary body/supraciliary space, not merely versus modern technologies, former approach capable giving better indication degree helping make decisions, postoperative management. In view this increasing number instruments our toolbox, choice choose patient increasingly challenging surgeon, keeping mind other important factors, including level type surgeon experience, availability different devices, reimbursement issues. factors come when deciding on procedure choose:•Age life expectancy•General health status, work, comorbid eye so forth•Type glaucoma•Angle status (narrow, closed, open)•Lens (phakic, cataract, pseudophakia, aphakia)•Level damage•Preoperative IOP•Target IOP•Refractive (myopia, presbyopia)•Past ocular comorbidities•Resource availability•Reimbursement issues Often several found appropriate, chosen considering surgeon’s experience comfort any given procedure. Fig. 1 summarizes available surgeon. indications subconjunctival This route opted uncontrolled maximal tolerated medical therapy, trial selective trabeculoplasty (SLT) if indicated. Surgeries group bringing (IOP) into low-teen values, rendering option requiring preoperative IOP. Patients scarred cicatricial conjunctiva those significant surface chronic blepharitis candidates route, healing suboptimal, bleb leaks failure, blebitis, tube microstent erosion. Blebs avoided contact lens wear necessary postoperatively. includes techniques, among commonly techniques today include deep sclerectomy (DS), viscocanalostomy, canaloplasty. DS aims promote primarily space thin trabeculo-Descemet membrane (TDM), providing resistance outflow. involves dissection superficial scleral flaplike trabeculectomy, followed deeper flap extending anteriorly clear cornea, unroofing outer wall leaving responsible filtration. inner canal can removed special forceps, possibly augmenting augmented use antifibrotics, mitomycin-C (MMC), enhance long term. co2 ablation called CLASS–co2 assisted minimizes perforation compared manual dissection. implantation collagen, hyaluronic acid, Hema implant, flap, keep patency intrascleral lake DS. Complications severe than trabeculectomy rehabilitation chance hypotony. Possible following:•Microperforations macroperforations intraoperatively iris incarceration. latter case, there need convert procedure.•Insufficient causing pressures postoperatively.•Postoperative hyphema, absorbs within few days without complications. Laser goniopuncture Q-switched 532-nm YAG needed half order TDM window postoperatively, structure prone scarring run, case insufficient Contraindications:•Neovascular (NVG)•Iridocorneal endothelial (ICE) syndrome•Chronic angle-closure (relative)•Posttraumatic angle recession extensive damage trabecular meshwork (TM) Literature comparison between NPGS shown contradictory results, because comparing techniques. A meta-analysis concluded MMC addition subscleral implant advisable, it gave no advantage raising complexity cost [[2]Gabai A. et al.Efficacy nonpenetrating open-angle glaucoma: meta-analysis.J Glaucoma. 2019; 28: 823-833Crossref (17) authors’ especially beneficial IOP myopia who hypotony [[3]Costa V.P. Arcieri E.S. Hypotony maculopathy.Acta Ophthalmol Scand. 2007; 85: 586-597Crossref (87) Viscocanalostomy canaloplasty natural outflow pathway, canal. performed similar DS, difference being instillation cohesive viscoelastic material (Healon GV) cut edges Canaloplasty variation viscocanalostomy dilation 360 using microcatheter (iTrack 250) placement permanent suture stretched (Fig. 3). These indicated primary (POAG) glaucomas (OAGs). They young mid- high-teens, mechanistically circumferential aqueous years, Cairns [[4]Cairns J.E. Trabeculectomy. Preliminary report method.Am J 1968; 66: 673-679Abstract Full Text PDF (793) creation access anterior chamber created creating bleb. An antimetabolite, 5-Fluorouracil (5-FU), prevent excessive hereby reduces endophthalmitis. (single digit) required, best chances achieving target. Care should taken operating highly myopic patients, develop Relative contraindications•Aphakic glaucoma•Active inflammation•Thin sclera hydrophilic composed porcine gelatin cross-linked glutaraldehyde. external diameter 150 μm internal lumen 45 μm, claimed provide approximately 6 8 mm Hg resistance, Hagen-Poiseuille law, protection against [[5]Samples J.R. I.I.K. Surgical innovations glaucoma. Springer. xi, New York2014: 307Google implanted shunting space. preferred standalone create blebs avoiding common nasal dysesthesia afterward. Xen Glaucoma Treatment System approved United States management where previous failed, POAG, pseudo-exfoliative (PXE), pigmentary unresponsive maximum therapy. described juvenile OAG uveitis [[6]Fea A.M. al.XEN..Clin 2020; 14: 1805-1832Crossref (21) Results from APEX study success around two-thirds years phacoemulsification POAG [[7]Reitsamer al.Two-year results multicenter medically glaucoma.Graefes Arch Clin Exp 257: 983-996Crossref (66) Another retrospective comparable profile year needling first [[8]Schlenker M.B. al.Efficacy, safety, trabeculectomy.Ophthalmology. 2017; 124: 1579-1588Abstract (146) advantages Gel Implant over filtering less-invasive favorable recovery, short duration, appropriate unable tolerate room time limited. MicroShunt 8.5-mm-long microincisional device 350-μm 70-μm lumen. poly(styrene-block-isobutylene-block-styrene), SIBS, biocompatible, bioinert material. via allowing hemostasis control, precise placement, verification flow. Aqueous humor flows posterior formed Tenon capsule. Several studies promising reducing medication burden, investigational yet Food Drug Administration (FDA) [[9]Schlenker al.Intermediate outcomes novel SIBS microshunt mitomycin C.Am 215: 141-153Abstract Scholar,[10]Batlle J.F. al.Three-year follow-up MicroShunt.J 2016; 25: e58-e65Crossref (73) largely past decades [[11]Arora K.S. al.Use various Medicare beneficiaries 1994 2012.Ophthalmology. 2015; 122: 1615-1624Abstract (140) Indications [[12]Vinod K. al.Practice preferences survey American Society.J 26: 687-693Crossref (88) involve insertion silicone chamber, sulcus, pars plana vitrectomized eyes, connected plate fixated 10 limbus, reservoir modulated fibrous capsule weeks preventing long-term divided valved, (New World Medical, Rancho Cucamonga, CA, USA), nonvalved implants, Baerveldt (Johnson & Johnson, Brunswick, NJ, Molteno (Katena Products, Parsippany, ClearPath Medical). following scenarios:1Patients surgeries, (TVT) randomized (RCT) eyes surgeries. had rate 5 rates early complications.2High NVG, recurrent uveitis, ICE syndrome, pediatric glaucoma.3Patients owing pemphigoid, Stevens Johnson forth. Pooled data analysis Comparison valved FP7 350-mm2 likely fail 5-year follow-up, [[13]Christakis P.G. al.Five-year pooled study.Am 176: 118-126Abstract (81) implants restricted flow 4 hypotony, makes exists immediate reduction extremely IOPs, whereas lower required cell loss persistent corneal edema, diplopia, erosion, When examining initial Primary TVT Baerveldt-350 mm2, arm. operation limited, suitable low-risk patients. Transscleral diode (TSCPC) guarded prognosis. employs handpiece ablate body’s secretory cells, therefore cells regenerative potential, treatments must get desired effect. Two modes delivery practice: continuous wave (CW-TSCPC) (MP-TLT). With CW-TSCPC, 18 24 spots treated 1.2 9 o’clock, nerves lie. Serious VA Snellen lines, intractable inflammation, phthisis, ensue, failed. MP-TLT relatively delivering duty cycles periods rest, thereby collateral tissue necrosis profile. exploratory reduced similarly 45%, re-treatment IOP-lowering medications. complication wave–treated prevalence NVG noted group. Finally, cyclodestruction endoscopic (ECP) probe, combination additional control reduction. only RCT ECP published lately phaco-ECP phaco (PACG) showing months arm [[14]Tóth M. al.Endoscopic open closure.Cochrane Database Syst Rev. (CD012741)PubMed SLT frequency-doubled neodymium-YAG mechanisms. known decrease 25% 30% variable extent scenarios [[15]Garg al.Primary hypertension: clinical outcomes, predictors success, hypertension trial.Ophthalmology. 126: 1238-1248Abstract (34) 360° gonioscopic view, multiple sessions. Main indications1Ocular hypertension2POAG normal-tension glaucoma3PXE glaucoma4Pigmentary glaucoma5Primary closure (PAC)/PACG patent iridectomy visible least 180°6Steroid-induced well tolerated, rare One beware spikes [[16]Harasymowycz P.J. al.Selective complicated elevation heavily pigmented meshworks.Am 2005; 139: 1110-1113Abstract (79) presented supplementary additive effect control. phakic pseudophakic attenuated response posttreatment period [[17]Shazly T.A. al.Effect outcome trabeculoplasty.Clin 2011; 5: 377-380Crossref (22) Contraindications:1Uncontrolled uveitic glaucoma2NVG3Poor visualization TM shows examples MIGS classified treatment. humans, 75% occur TM, supposed stem juxtacanalicular [[18]Gillmann Mansouri Minimally invasive evidence?.Asia Pac (Phila). 9: 203-214Crossref (12) Scholar,[19]Grant W.M. Further facility meshwork.AMA 1958; 60: 523-533Crossref (174) Mounting consists levels contributing total resistance: permeability collapse downstream distal [[20]Maepea O. Bill Pressures Schlemm's monkeys.Exp Eye Res. 1992; 54: 879-883Crossref (223) Therefore, targeting augment physiologic conventional pathway impaired Although episcleral venous (EVP) best, far known. general FDA conjunction countries, they stand-alone even [[21]Andrew N.H. Akkach S. Casson R.J. review relevance surgery.Surv 65: 18-31Abstract (15) Procedures falling category subdivided subcategories mechanism action:1Removal canal2Disruption canal3Implantation bypass TM4Dilation Table either aforementioned subcategories, relevant select studies.Table 1Minimally efficacyRemoval (ab trabeculectomy)DeviceManufacturerDesign techniqueEfficacyTrabectomeNeoMedix, Tustin, USASingle-use electrocautery irrigation aspiration unit, removal 60°–120° meshworkInconclusive regarding efficacySeventy-eight percent achieve 15 20% medications y [[22]Nichani P. al.Micro-invasive 3476 eyes.Surv Scholar]Kahook Dual BladeNew disposable blade sharp tip, pierce meshwork, ramp stretches dual parallel blades, paired incisions meshworkPhaco Kahook Blade phaco-iStent burden [[23]Le C. al.Surgical iStent goniotomy minimum 12-month follow-up.J 411-414Crossref (20) Scholar,[24]ElMallah M.K. al.12-month excisional glaucomatous surgery.Adv Ther. 36: 2515-2527Crossref (25) Scholar]Bent AbInterno Needle GoniectomyTrabeculotomy bent tip 25-gauge needleNo availableDisruption trabeculotomy)DeviceManufacturerDesign techniqueGonioscopy-assisted transluminal (GATT)Ellex iScience, Fremont, USATrabeculotomy 180°–360° 250-μm iTrack fiberoptic canalTrabeculotomy Prolene 5-0 sutureEfficacy reported primary, secondary, [[25]Grover D.S. al.Gonioscopy trabeculotomy: trabeculotomy congenital glaucoma.Br 99: 1092-1096Crossref (74) Scholar,[26]Grover al.Outcomes gonioscopy-assisted (GATT) surgery.J 41-45Crossref (45) Scholar]Younger age predictive [[27]Salimi al.Gonioscopy-assisted younger middle-aged adults: one-year outcomes.Ophthalmol 2021; 4: 162-172Abstract (6) Scholar]Trab360/OMNISight Sciences, Menlo Park, advancing opposite 180 trabeculotomiesImplantation meshworkDeviceManufacturerDesign techniqueiStent G1Glaukos Corporation, San Clemente, USASnorkel-shaped heparin-coated, nonferromagnetic titanium stentCentral inlet: 120 μmAt 48 mo 14.2% between-group favor iStent-phaco vs phaco-only statistically mean reduction, group, arms [[28]Fea al.Micro-bypass phacoemulsification: 4-year 2015: 795357Crossref (61) Scholar]iStent inject-WGlaukos USABullet-shaped stentInject: 0.36 width × 0.23 heightCentral 80 μmInject: W: mo, 75.8% inject 61.9% experienced ≥20% baseline unmedicated IOP, 83% [[29]Samuelson T.W. al.Prospective, randomized, pivotal micro-bypass cataract: two-year results.Ophthalmology. 811-821Abstract (77) Scholar]HydrusIvantis Inc, Irvine, USABiocompatible nitinol 8-mm-long openingsInc