Ab Interno Approach Research Articles

A First-in-Human Study of the Efficacy and Safety of MINIject in Patients with Medically Uncontrolled Open-Angle Glaucoma (STAR-I)

To describe the safety and efficacy of a novel, supraciliary, microinvasive glaucoma surgery drainage system, MINIject (iSTAR Medical, Wavre, Belgium), in the study. Prospective, multicenter, interventional, single-arm trial. Twenty-six patients with primary open-angle glaucoma uncontrolled with 1 or more intraocular pressure (IOP)-lowering medications. Using an ab interno approach, 25 eyes were implanted successfully in a stand-alone procedure with a 5-mm long device made of biocompatible STAR material, which is soft and flexible silicone in a microporous, network design. Intraocular pressure, medication use, and other ocular parameters were evaluated before surgery, 1 day, 1 and 2 weeks, and 1, 3, and 6 months after surgery. Intraocular pressure reduction at 6 months compared with baseline analyzed using a paired t test. Safety evaluation entailed tabulation of the nature and frequency of adverse events. Mean baseline diurnal IOP was 23.2 mmHg (standard error, 0.6 mmHg) using a mean ± standard deviation of 2.0±1.1 IOP-lowering medication classes. During the 6-month follow-up period, mean IOP ranged from 10.0-16.3 mmHg (mean reductions, 6.9-13.2 mmHg or 31.0%-56.8%). Six months after surgery, mean diurnal IOP was 14.2 mmHg (standard error, 0.9 mmHg), equivalent to a reduction of 9.0 mmHg or 39.1% (P < 0.0001). The mean ± standard deviation number of IOP-lowering medications was 0.3±0.7. Of 24 patients seen at 6-month follow-up, 21 (87.5%) were medication-free and 23 (95.8%) achieved a minimum 20% IOP reduction from baseline. There were no serious adverse events related to the device or procedure, and no additional glaucoma surgery was required. Frequently reported events included anterior chamber inflammation (n= 8), IOP elevation (n= 6), of which 1 event was an IOP spike per protocol, visual acuity reduction (n= 3), and hyphema (n= 3), all of which resolved. There was no change to mean central or peripheral corneal endothelial cell density. No device-related adverse events were reported. The MINIject glaucoma drainage system significantly lowered IOP and eliminated the need for medication in most patients 6 months after surgery when implanted in a standalone procedure. There were no serious ocular adverse events.

Ab-interno trabeculotomy-related glaucoma surgeries.

Reductions of intraocular pressure during trabeculotomy result from relieving the resistance to aqueous flow by cleavage of the trabecular meshwork and inner walls of Schlemm's canal at the point of outflow resistance of the aqueous humor. Since trabeculotomy does not result in bleb formation, development of late-onset sight-threatening complications, such as hypotony maculopathy and endophthalmitis, that are associated occasionally with trabeculectomy develop less frequently after trabeculotomy. The ab-interno approach is used in several new procedures, including the Trabectome, Kahook Dual Blade, microhook abinterno trabeculotomy, and 360° suture trabeculotomy, instead of the ab-externo approach as in conventional trabeculotomy. These newly developed novel, minimally invasive, and trabeculotomy-related glaucoma surgeries can be good options for certain glaucoma cases, including early-stage open-angle glaucoma, developmental glaucoma, and glaucoma in elderly patients.

Viscodilation of Schlemm's canal for the reduction of IOP via an ab-interno approach.

PurposeThe aim of this study was to compare the 1-year efficacy and safety profile of ab-interno canaloplasty (ABiC) when performed as a stand-alone procedure or as an adjunct to cataract extraction in reducing IOP and glaucoma medication dependence.Patients and methodsThis retrospective, comparative, consecutive case series included patients with uncontrolled primary open-angle glaucoma (POAG) who underwent ABiC as a stand-alone procedure or in conjunction with cataract extraction. Data were collected over a 12-month period. Primary outcome measures were mean lower IOP and mean number of glaucoma medications. Secondary endpoints included surgical and postsurgical complications and secondary interventions.ResultsThe study included 75 eyes of 68 patients (mean age: 73.7±9.9 years) with a mean baseline IOP of 20.4±4.7 mmHg on 2.8±0.9 medications, which reduced to 13.3±1.9 mmHg (n=73) on 1.1±1.1 medications at 12 months postoperative (both P<0.0001). At 12 months, 40% of eyes were medication free. In the ABiC/phacoemulsification subgroup (n=34 eyes), the mean IOP and medication use decreased from 19.4±3.7 mmHg on 2.6±1.0 medications preoperatively to 13.0±1.8 mmHg on 0.8±0.2 medications at 12 months (both P<0.001). In the stand-alone ABiC subgroup (n=41), the mean IOP and medication use decreased from 21.2±5.3 mmHg on 3.0±0.7 medications preoperatively to 13.7±1.9 mmHg on 1.3±1.1 medications at 12 months (P=0.001 and <0.001, respectively). No serious adverse events were recorded.ConclusionThese data demonstrate that ABiC was effective at reducing IOP and medication use in eyes with uncontrolled POAG with or without cataract surgery.

Prospective Evaluation of Two iStent® Trabecular Stents, One iStent Supra® Suprachoroidal Stent, and Postoperative Prostaglandin in Refractory Glaucoma: 4-year Outcomes.

IntroductionThis study evaluates long-term outcomes of two trabecular micro-bypass stents, one suprachoroidal stent, and postoperative prostaglandin in eyes with refractory open angle glaucoma (OAG).MethodsProspective ongoing 5-year study of 80 eligible subjects (70 with 4-year follow-up) with OAG and IOP ≥ 18 mmHg after prior trabeculectomy and while taking 1–3 glaucoma medications. Subjects received two iStent® trabecular micro-bypass stents, one iStent Supra® suprachoroidal stent, and postoperative travoprost. Postoperative IOP was measured with medication and annually following medication washouts. Performance was measured by the proportion of eyes with ≥ 20% IOP reduction on one medication (the protocol-specified prostaglandin) versus preoperative medicated IOP (primary outcome); and the proportion of eyes with postoperative IOP ≤ 15 and ≤ 18 mmHg on one medication (secondary outcome). Additional clinical and safety data included medications, visual field, pachymetry, gonioscopy, adverse events, visual acuity, and slit-lamp and fundus examinations.ResultsPreoperatively, mean medicated IOP was 22.0 ± 3.1 mmHg on 1.2 ± 0.4 medications, and mean unmedicated IOP was 26.4 ± 2.4 mmHg. Postoperatively, among eyes without later cataract surgery, mean medicated IOP at all visits through 48 months was ≤ 13.7 mmHg (≥ 37% reduction), and annual unmedicated IOP was ≤ 18.4 mmHg (reductions of ≥ 30% vs. preoperative unmedicated IOP and ≥ 16% vs. preoperative medicated IOP). At all postoperative visits among eyes without additional surgery or medication, ≥ 91% of eyes had ≥ 20% IOP reduction on one medication versus preoperative medicated IOP. At month 48, 97 and 98% of eyes achieved IOP ≤ 15 and ≤ 18 mmHg, respectively, on one medication. Six eyes required additional medication, no eyes required additional glaucoma surgery, and safety measurements were favorable throughout follow-up.ConclusionIOP control was achieved safely with two trabecular micro-bypass stents, one suprachoroidal stent, and postoperative prostaglandin. This microinvasive, ab interno approach introduces a possible new treatment option for refractory disease.Trial RegistrationNCT01456390.FundingGlaukos Corporation.Electronic supplementary materialThe online version of this article (10.1007/s12325-018-0666-4) contains supplementary material, which is available to authorized users.

Navigating a new direction in micro-invasive glaucoma surgery: results from the COMPASS trial

Recent innovations and technological advances have ushered in a new era of surgical approaches to glaucoma management. Our options have expanded beyond traditional incisional glaucoma surgery (i.e., trabeculectomy and tube shunts) to include newer procedures that can be implemented earlier in patients with milder disease. Many of these recently introduced operations can be classified as micro-invasive glaucoma surgery (MIGS), for which five defining criteria have been proposed: an ab interno approach; minimal tissue trauma; at least modest efficacy; high safety; and rapid recovery (1). Candidates for currently available MIGS are generally those with early glaucoma whose disease does not require very low intraocular pressure (IOP) to retard progression and/or who may benefit from reduction in medical therapy.

Update on Microinvasive Glaucoma Surgery.

Update on Microinvasive Glaucoma Surgery.

Schlemm canal stenting

SummaryIn primary open‐angle glaucoma, the juxtacanalicular trabecular meshwork and inner wall of Schlemm canal are believed to be the site of greatest resistance to aqueous outflow. Recently several new minimally invasive devices have been developed to bypass this tissue and provide direct access to low resistance collector channels in the outer wall of Schlemm canal. These devices are inserted via an ab interno approach, usually at the time of cataract surgery, and are designed to lower intraocular pressure and reduce or eliminate the need for glaucoma medications. This Special Interest Symposium reviews the growing evidence base and covers techniques and pearls for the insertion of both the iStent and iStent Inject (Glaukos Corporation, Laguna Hills, CA, USA) as well as the Hydrus intracanalicular scaffold (Ivantis Inc., Irvine, CA, USA).

Micro-invasive glaucoma surgery (MIGS): a review of surgical procedures using stents.

Over the last decade several novel surgical treatment options and devices for glaucoma have been developed. All these developments aim to cause as little trauma as possible to the eye, to safely, effectively, and sustainably reduce intraocular pressure (IOP), to produce reproducible results, and to be easy to adopt. The term “micro-invasive glaucoma surgery (MIGS)” was used for summarizing all these procedures. Currently MIGS is gaining more and more interest and popularity. The possible reduction of the number of glaucoma medications, the ab interno approach without damaging the conjunctival tissue, and the probably safer procedures compared to incisional surgical methods may explain the increased interest in MIGS. The use of glaucoma drainage implants for lowering IOP in difficult-to-treat patients has been established for a long time, however, a variety of new glaucoma micro-stents are being manufactured by using various materials and are available to increase aqueous outflow via different pathways. This review summarizes published results of randomized clinical studies and extensive case report series on these devices, including Schlemm’s canal stents (iStent®, iStent® inject, Hydrus), suprachoroidal stents (CyPass®, iStent® Supra), and subconjunctival stents (XEN). The article summarizes the findings of published material on efficacy and safety for each of these approaches.

Rapid Intraocular Tube Trimming for Glaucoma Drainage Implant Devices

To describe a new approach for shortening silicone tubes of glaucoma drainage devices (GDDs). A retrospective intervention case series describing 3 patients undergoing the same treatment at a single institutional center RESULTS:: Three patients underwent successful ab interno trimming of GDD silicone tubes without complication CONCLUSIONS:: This technique allows for rapid and successful shortening of GDD tubes via an ab interno approach avoiding risks of traditional glaucoma tube trimming approaches.

Microinvasive glaucoma surgeries

Because of the complications of current penetrating glaucoma surgeries as in trabeculectomy or glaucoma drainage devices, there is now an increased interest in newly introduced microinvasive glaucoma surgeries, which provide a safer and not a less-efficient alternative for such procedures, along with a decrease in dependence of glaucoma medications postoperatively. The microscopic implants can be implanted by following either an ab-interno approach (e.g. iStent, CyPass, Trabectome, and Xen Gel microshunt) or an ab-externo approach (e.g. Ex-Press minishunt and canaloplasty). The procedures aim to utilize the trabecular pathway, suprachoroidal space, or the subconjunctival space to increase aqueous drainage. These procedures can be performed in conjunction with phacoemulsification to augment the intraocular pressure-lowering effect, and the devices can be implanted during the same session without or with minimal additional risk.

Advances in Glaucoma Surgery

Currently popular glaucoma filtration surgeries which include trabeculectomy and glaucoma drainage devices have their share of vision-threatening complications. Lately less invasive and safer devices have been developed to be used alone or in conjunction with cataract surgery for lowering the intraocular pressure. These microscopic implants utilize the trabecular pathway, suprachoroidal pathway or subconjunctival route for drainage. The term ‘Micro-Invasive Glaucoma Surgery’ includes surgical procedures that use an ab-interno approach, such as iStent, Trabectome, Hydrus Scaffold shunt, Excimer laser trabeculotomy and CyPass suprachoroidal shunt. Implants which utilize ab-externo approach are canaloplasty with microcatheter, Ex-PRESS glaucoma microshunts, SOLX Gold shunt and Aquashunt. Studies are ongoing to evaluate their efficacy alone or in combination with phacoemulsification and have found encouraging results in early to moderate glaucoma.

Two-Year COMPASS Trial Results: Supraciliary Microstenting with Phacoemulsification in Patients with Open-Angle Glaucoma and Cataracts

We evaluated 2-year safety and efficacy of supraciliary microstenting (CyPass Micro-Stent; Transcend Medical, Inc., Menlo Park, CA) for treating mild-to-moderate primary open-angle glaucoma (POAG) in patients undergoing cataract surgery. Multicenter (24 US sites), interventional randomized clinical trial (RCT) (ClinicalTrials.gov identifier, NCT01085357). Subjects were enrolled beginning July 2011, with study completion in March 2015. Subjects had POAG with mean diurnal unmedicated intraocular pressure (IOP) 21-33 mmHg and were undergoing phacoemulsification cataract surgery. After completing cataract surgery, subjects were intraoperatively randomized to phacoemulsification only (control) or supraciliary microstenting with phacoemulsification (microstent) groups (1:3 ratio). Microstent implantation via an ab interno approach to the supraciliary space allowed concomitant cataract and glaucoma surgery. Outcome measures included percentage of subjects achieving ≥20% unmedicated diurnal IOP lowering versus baseline, mean IOP change and glaucoma medication use, and ocular adverse event (AE) incidence through 24 months. Of 505 subjects, 131 were randomized to the control group and 374 were randomized to the microstent group. Baseline mean IOPs in the control and microstent groups were similar: 24.5±3.0 and 24.4±2.8 mmHg, respectively (P > 0.05); mean medications were 1.3±1.0 and 1.4±0.9, respectively (P > 0.05). There was early and sustained IOP reduction, with 60% of controls versus 77% of microstent subjects achieving ≥20% unmedicated IOP lowering versus baseline at 24 months (P= 0.001; per-protocol analysis). Mean IOP reduction was ↓7.4 mmHg for the microstent group versus ↓5.4 mmHg in controls (P < 0.001), with 85% of microstent subjects not requiring IOPmedications at 24 months. Mean 24-month medication use was 67% lower in microstent subjects (P<0.001); 59% of control versus 85% of microstent subjects were medication free. Mean medication use in controls decreased from 1.3±1.0 drugs at baseline to 0.7±0.9 and 0.6±0.8 drugs at 12 and 24 months, respectively, and in the microstent group from 1.4±0.9 to 0.2±0.6 drugs at both 12 and 24 months (P < 0.001 for reductions in both groups at both follow-ups vs. baseline). No vision-threatening microstent-related AEs occurred. Visual acuity was high in both groups through 24 months; >98% of all subjects achieved 20/40 best-corrected visual acuity or better. This RCT demonstrated safe and sustained 2-year reduction in IOP and glaucoma medication use after microinterventional surgical treatment for mild-to-moderate POAG.

Post-operative hospitalization in retinal detachment correlation to recurrences.

To evaluate relationships between the incidence of re-detachment and postoperative days of hospitalization in patients with diagnosis of retinal detachment (RD) who underwent surgery either through ab-externo approach (scleral buckling and encircling) or ab-interno approach (vitrectomy and oil-gas tamponade). This retrospective study included 268 patients (268 eyes) with diagnosis of primary RD: 127 males (47%) and 141 (53%) females, mean age of 64.1 ± 17.3 years. 46 patients (17%) underwent a surgical ab-externo approach (group A), while 222 patients (83%) underwent an ab-interno surgical approach. Each RD was graded according to the "Retinal detachment grading system of Royal College of Ophthalmologists" and treated within 5 days after diagnosis. The redetachment (RT) related to a surgical failure was considered within 30 days after first operation. In the group 1 without night hospitalization (day surgery) global RT rate was 3.5% (4.17% for ab-interno technique and 0% for ab-externo techniques). In the group 2 with one day of hospitalization global RT rate was 1.33% (1.49% for ab-interno technique and 0% for ab-externo techniques). In the group 3 with 2 days of hospitalization global RT rate was 3.80% (4.62% for ab-interno techniques and 0% for ab-externo techniques). In the group 4 with 3 or more days of hospitalization global RT rate was 12.28% (14.29% for ab-interno techniques for 6.67% ab-externo techniques). The incidence of RT in group 1, day surgery, is comparable to the other groups and it is less compared to group 4 (3 or more days of hospitalization). The incidence of retinal redetachment (RRD) is not increased in day surgery mode. These data support outpatient management of RD patients to reduce medical cost and problems related to the hospitalization. Further studies are needed for patients' security.

Modern methods of minimally invasive glaucoma surgery

Over the years, glaucoma surgery has improved from iridectomy by A. Graefe and traumatizing procedures performed without magnification tools or microsurgical instrument to high-technology interventions that are not only microscopic, but also pathogenetically oriented. Various modifications of trabeculectomy, initially introduced by J. Cairns back in 1968, had been the gold standard for several decades and were notable for pronounced and stable hypotensive effects. However, there was also a strong association with such complications as choroidal detachment and hyphema, thus, boosting the development of so called nonfistulizing surgeries. Of the latter, the most widely used are non-penetrating procedures, including deep sclerectomy and viscocanalostomy. Although very safe, they appear unable to produce a truly long-lasting hypotensive effect. Moreover, just as fistulizing trabeculectomy, non-penetrating procedures damage the limbus and adjacent conjunctiva reducing the possibility of a second intervention. This fact together with other drawbacks mentioned above, on the one hand, and technical progress, on the other, were essential prerequisites for the appearance of a new type of surgery - minimally invasive glaucoma surgery (MIGS). Parameters that should be met for a procedure to be considered minimally invasive are debated. The main requirement has, however, been established: ab interno approach through a corneal incision. As surgical tools are enhanced and new techniques arise, options for glaucoma treatment widen greatly, ensuring our future move to higher level standards in the field. This review contains all recent data on minimally invasive techniques currently in use in glaucoma surgery or those under investigation. The authors have also analyzed effectiveness reports and present their conclusions regarding the current state of MIGS worldwide.

Minimally invasive glaucoma surgery: current status and future prospects.

Minimally invasive glaucoma surgery aims to provide a medication-sparing, conjunctival-sparing, ab interno approach to intraocular pressure reduction for patients with mild-to-moderate glaucoma that is safer than traditional incisional glaucoma surgery. The current approaches include: increasing trabecular outflow (Trabectome, iStent, Hydrus stent, gonioscopy-assisted transluminal trabeculotomy, excimer laser trabeculotomy); suprachoroidal shunts (Cypass micro-stent); reducing aqueous production (endocyclophotocoagulation); and subconjunctival filtration (XEN gel stent). The data on each surgical procedure for each of these approaches are reviewed in this article, patient selection pearls learned to date are discussed, and expectations for the future are examined.

Micro-invasive 360-degree suture trabeculotomy after successful canaloplasty – one year results.

This study was conducted to analyse the intraocular pressure (IOP)-lowering and drug-sparing effect of micro-invasive 360-degree suture trabeculotomy after successfully performed canaloplasty. This retrospective interventional study included patients with open angle glaucoma or secondary forms of glaucoma, suffering from insufficient IOP level after previously conducted canaloplasty. To enhance the IOP-lowering canaloplasty effect, all patients underwent micro-invasive 360-degree suture trabeculotomy as a conjunctiva-sparing ab interno approach for circumferential trabeculotomy. This was achieved by introducing end-gripping forceps into the anterior chamber with topical anaesthesia, and grasping and extracting the canaloplasty suture through the trabecular meshwork under gonioscopic visualisation. Main outcome measures were IOP reduction and the number of IOP-lowering medications after 3 and 12 moths. Intraoperative and postoperative complications were documented systematically. In total, 88 eyes of 88 patients were included. Mean IOP reduction after micro-invasive 360-degree suture trabeculotomy at month 3 was 37.5 % (from baseline 22.8 ± 6.7 mmHg to 14.3 ± 3.1 mmHg, p < 0.01) and 41.2 % after 12 months (from 22.8 ± 6.7 mmHg to 13.4 ± 2.3 mmHg, p < 0.01). The number of IOP-lowering medications decreased significantly from a mean of 2.7 ± 1.4 to 1.3 ± 1.4 after 3 months, and 1.6 ± 1.2 after 12 months. No serious complications were observed. However, mild or moderate retrograde bleeding from the collector channels was present in 25 % of eyes that resorbed spontaneously in all cases. Micro-invasive 360-degree suture trabeculotomy represents a simple and safe minimal invasive ab interno technique to postoperatively enhance the IOP-lowering and drug-sparing effect of canaloplasty.

Micro-invasive suture trabeculotomy after canaloplasty: preliminary results.

In this study, a conjunctival-sparing ab interno approach for circumferential trabeculotomy, termed micro-invasive suture trabeculotomy (MIST) and its preliminary results are presented. Retrospective case-series in a university setting. A total of 31 patients with open-angle glaucoma with history of canaloplasty. A conjunctival-sparing ab interno approach for circumferential trabeculotomy, termed MIST. Mean decrease of intraocular pressure (IOP) and number of pressure-lowering medications. Mean decrease of IOP was 11.1 mmHg (standard deviation [SD], 9.9 mmHg) at 6 months, 12.1 mmHg (SD, 10.5 mmHg) at 12 months and 13.5 mmHg (SD, 11.4 mmHg) at 24 months. The average percent lowering of IOP was 36.7% (SD, 32.8%) at 6 months, 41.4% (SD, 35.9%) at 12 months and 44.6% (SD, 37.7%) at 24 months. The number of pressure-lowering medications decreased by 1.1 (SD, 1.3) at month 6, by 1.2 (SD, 1.5) at month 12, and by 1.3 (SD, 1.6) at month 24. MIST is a promising approach for the treatment of open-angle glaucoma, which is insufficiently controlled with canaloplasty. The procedure achieved significant and sustained lowering of the intraocular pressure and demonstrated an excellent safety profile. The main advantages of the procedure are: easy to learn, fast to perform, and sparing of the conjunctiva for further filtration surgery, if necessary.

Emerging surgical therapy in the treatment of glaucoma.

There is general consensus that surgery gives a better intraocular pressure (IOP) control than medical therapy, but surgery may be affected by complications and failures, and for this reason nowadays, it is reserved to advanced or clearly progressive glaucoma. In recent years, there have been a lot of efforts to enhance safety and efficacy of conventional surgery as to find new techniques more safer and more effective. Actually, this is a field in rapid evolution, and we have a great number of innovative procedures, often working on complete different basis. These procedures are classified according to their mechanism of action and the type of surgical approach, in order to clearly understand of what we are speaking about. From a general point of view, surgical procedures may be divided in procedures that increase outflow and procedures that reduce aqueous production: most of these procedures can be performed with an ab externo or an ab interno approach. The ab interno approach has great advantages and enormous potential of development; probably, its diffusion will be facilitated by the development of new devices for angle visualization. Nevertheless, it is important to remember that actually none of the new procedures has been validated in large controlled clinical trials and none of the new procedures is indicated when IOP target is very low.

Ab interno approach to the subconjunctival space using a collagen glaucoma stent

This review considers a minimally invasive ab interno approach to glaucoma filtration surgery. Glaucoma filtration surgery can be defined as an attempt to lower intraocular pressure (IOP) by the surgical formation of an artificial drainage pathway from the anterior chamber to the subconjunctival space. Subconjunctival drainage of aqueous fluid has been a cornerstone of glaucoma surgery for more than a century. Varying techniques have been deployed to provide access to this space. Yet, despite numerous innovations in filtering surgery to achieve safe IOP reduction, too many short-term and long-term complications are associated with this surgery. This article describes the development of a new, soft, and permanent ab interno collagen implant (XEN gel stent) to optimize aqueous drainage to the subconjunctival space. Specific characteristics are critical in designing such an implant. Determining the optimum size of the device lumen to avoid hypotony while maximizing long-term outflow is crucial. Other topics discussed include material, length, diameter, flexibility, stability, and biocompatibility of the implant. Preclinical and human eye testing shows that the implant does not seem to occlude inside the lumen and the implant material does not appear to cause tissue reaction in the eye. The ab interno placement of the stent offers an alternative for lowering IOP with a minimally invasive procedure, minimum conjunctival tissue disruption, restricted flow to avoid hypotony, and long-term safety. Dr. Lewis received financial support from Aquesys, Inc. as a consultant.

Gonioscopy-assisted transluminal trabeculotomy, ab interno trabeculotomy: technique report and preliminary results.

To introduce a minimally invasive, ab interno approach to a circumferential 360-degree trabeculotomy and to report the preliminary results. Retrospective, noncomparative cases series. Eighty-five eyes of 85 consecutive patients who sought treatment at Glaucoma Associates of Texas with uncontrolled open-angle glaucoma and underwent gonioscopy-assisted transluminal trabeculotomy (GATT) for whom there was at least 6 months of follow-up data. Retrospective chart review of patients who underwent GATT by 4 of the authors (D.S.G., D.G.G., O.S., R.L.F.) between October 2011 and October 2012. The surgery was performed in adults with various open-angle glaucomas. Intraocular pressure (IOP), glaucoma medications, visual acuity, and intraoperative as well as postoperative complications. Eighty-five patients with an age range of 24 to 88 years underwent GATT with at least 6 months of follow-up. In 57 patients with primary open-angle glaucoma, the IOP decreased by 7.7 mmHg (standard deviation [SD], 6.2 mm Hg; 30.0% [SD, 22.7%]) with an average decrease in glaucoma medications of 0.9 (SD, 1.3) at 6months. In this group, the IOP decreased by 11.1 mmHg (SD, 6.1 mmHg; 39.8% [SD, 16.0%]) with 1.1 fewer glaucoma medications at 12 months. In the secondary glaucoma group of 28 patients, IOP decreased by 17.2 mmHg (SD, 10.8 mmHg; 52.7% [SD, 15.8%]) with an average of 2.2 fewer glaucoma medications at 6 months. In this group, the IOP decreased by 19.9 mmHg (SD, 10.2 mmHg; 56.8% [SD, 17.4%]) with an average of 1.9 fewer medications (SD, 2.1) at 12 months. Treatment was considered to have failed in 9% (8/85) of patients because ofthe need for further glaucoma surgery. The cumulative proportion of failure at 1 year ranged from 0.1 to 0.32, depending on the group. Lens status or concurrent cataract surgery did not have a statistically significant effect on IOP in eyes that underwent GATT at either 6 or 12months (P > 0.35). The most common complication was transient hyphema, seen in 30% of patients at the 1-week visit. The preliminary results and safety profile for GATT, a minimally invasive circumferential trabeculotomy, are promising and at least equivalent to previously published results for ab externo trabeculotomy.