Microinvasive Glaucoma Surgery Research Articles

Trends in Glaucoma Surgeries Performed by Glaucoma Subspecialists versus Nonsubspecialists on Medicare Beneficiaries from 2008 through 2016

To characterize the use of laser and incisional glaucoma surgeries among Medicare beneficiaries from 2008 through 2016 and to compare the use of these surgeries by glaucoma subspecialists versus nonsubspecialists. Retrospective, observational analysis. Medicare beneficiaries (n = 1 468 035) undergoing ≥1 laser or incisional glaucoma surgery procedure during 2008 through2016. Claims data from a 20% sample of enrollees in fee-for-service Medicare throughout the United States were analyzed to identify all laser and incisional glaucoma surgeries performed from 2008 through 2016. We assessed use of traditional incisional glaucoma surgery techniques (trabeculectomy and glaucoma drainage implant [GDI] procedure) and microinvasive glaucoma surgery (MIGS). Enrollee and procedure counts were multiplied by 5 to estimate use throughout all of Medicare. Linear regression was used to compare trends in use of glaucoma surgeries between ophthalmologists who could be characterized as glaucoma subspecialists versus nonsubspecialists. Numbers of laser and incisional glaucoma surgeries performed overall and stratified by glaucoma subspecialist status. The number of Medicare beneficiaries undergoing any glaucoma therapeutic procedure increased by 10.6%, from 218 375 in 2008 to 241 565 in 2016. The total number of traditional incisional glaucoma surgeries decreased by 11.7%, from 37 225 to 32 885 (P= 0.02). The total number of MIGS procedures increased by 426% from 13 705 in 2012 (the first year MIGS codes were available) to 58 345 in 2016 (P= 0.001). Throughout the study period, glaucoma subspecialists performed most of the trabeculectomies (76.7% in 2008, 83.1% in 2016) and GDI procedures (77.7% in 2008, 80.6% in 2016). Many MIGS procedures were performed by nonsubspecialists. The proportions of endocyclophotocoagulations, iStent (Glaukos; San Clemente, CA) insertions, goniotomies, and canaloplasties performed by glaucoma subspecialists in 2016 were 22.0%, 25.2%, 56.9%, and 62.8%, respectively. From 2008 through 2016, a large shift in practice from traditional incisional glaucoma surgeries to MIGS procedures was observed. Although glaucoma subspecialists continue to perform most traditional incisional glaucoma surgeries, many MIGS procedures are performed by nonsubspecialists. These results highlight the importance of training residents in performing MIGS procedures and managing these patients perioperatively. Future studies should explore the impact of this shift in care on outcomes and costs.

A Survey of Glaucoma Surgery Practice Patterns in the Veterans Health Administration.

Glaucoma surgical practice patterns are not well described in the United States (US). This study aims to evaluate the indications for and potential barriers to glaucoma surgery in the Veterans Health Administration (VHA). An anonymous 10-question survey using REDCap (Nashville, TN) software was sent by mail (with web link) and email to ophthalmology chiefs at the 86 academically affiliated Veterans Affairs Medical Centers (VAMCs). Academic-affiliated VAMCs were selected because of their patient range and role in ophthalmic education. Non-responders received two reminder e-mails and two phone calls; the survey was closed after 6 weeks. The data were analyzed using descriptive statistics. The response rate was 45% (39/86). Most respondents (92%) worked in an integrated eye clinic with both ophthalmology and optometry services. Almost half of the respondents (49%; 19/39) believed that laser trabeculoplasty (LTP) was an option for initial glaucoma therapy. Noncompliance was a commonly reported indication for LTP (95%), tube shunt procedures (65%), micro-invasive glaucoma surgery (59%), and trabeculectomy (48.7%). One third of the respondents believed that there were delays in glaucoma care. The respondents noted that significant barriers in access to surgery included lack of transportation (69%), scheduling challenges (62%), and delayed referral (62%). This survey of glaucoma surgery practice patterns highlights the growing role of LTP and suggests that non-compliance and access remain significant barriers to glaucoma surgical care within the VHA.

Explantation of the CyPass implant in acase series of patients with corneal decompensation

In microinvasive glaucoma surgery (MIGS) the CyPass microstent (Alcon Inc.) was implanted in the suprachoroidal space to increase the uveoscleral outflow, thereby lowering the intraocular pressure. Due to the excessive loss of corneal endothelial cells, the implant was withdrawn from the global market in August 2018. Aloss of corneal endothelial cells was observed in 6patients (8eyes in total) with early to moderate primary open-angle glaucoma 3years after CyPass implantation. One eye developed abullous keratopathy. In all patients an implant migration in the anterior chamber compared to the original postoperative position was detected, with more than one ring of the CyPass implant being visible in the anterior chamber. In all eight cases the CyPass implant was removed. The local therapy with cortisone eye drops in combination with a5% sodium chloride solution did not improve chronic corneal edema in one patient. Therefore, aDescemet membrane endothelial keratoplasty (DMEK) was performed with postoperative improvement of visual acuity. In patients with more than one visible ring of the CyPass implant in the anterior chamber and subsequent localized loss of corneal endothelial cells, CyPass trimming or removal is recommended to avoid the progression of generalized corneal endothelial cell reduction and the onset of refractory, chronic corneal edema.

Subconjunctival microinvasive glaucoma surgeries: an update on the Xen gel stent and the PreserFlo MicroShunt.

This review will provide an update on surgical techniques, outcomes, and complications for two new translimbal bleb-forming surgical glaucoma devices. The XEN Gel Microstent and PreserFlo MicroShunt comprise a category of subconjunctival microinvasive glaucoma surgery developed with the aim of improving the predictability and safety profile of bleb-forming procedures. Both devices are made of noninflammatory material which limits postsurgical inflammation and scarring and have a valve-less intrinsic flow-limiting design, which decreases the risk of hypotony. There are various techniques of implantation for the XEN Gel Microstent each with their own advantages and disadvantages. These devices have demonstrated promising outcomes in early experimental literature with similar intraocular pressure-lowering effects to traditional incisional surgery such as trabeculectomy or tube shunt surgery, but with fewer risks. Future randomized, prospective studies should be done to compare these gel stents and microshunts both to each other and to other traditional glaucoma surgeries.

Circumferential canal surgery: a brief history.

Purpose of reviewMost microinvasive glaucoma surgery (MIGS) procedures bypass outflow resistance residing proximally in the trabecular meshwork and inner wall of Schlemm's canal. A novel procedure combining trabeculotomy with viscodilation adds to this by also addressing distal resistance of the canal and collector channel ostia. This review examines the development and evidence for both trabeculotomy and canaloplasty separately and the combination in a single procedure.Recent findingsRecent aqueous angiography studies have confirmed the segmental nature of outflow through Schlemm's canal highlighting the need to address distal outflow pathway resistance. Combined trabeculotomy and viscodilation ab interno is a novel approach with a new purpose-designed device (OMNI Surgical System) becoming available to surgeons in early 2018. Recent results as both a standalone and combined with cataract procedure demonstrate significant intraocular pressure reductions with an average 41% reduction from baseline in the pseudophakic group.SummaryTargeting both distal as well as proximal points of outflow resistance in the conventional pathway may prove to be a highly efficacious MIGS modality. Additional large prospective studies are currently ongoing to confirm these preliminary results.

Prospective Studies of Minimally Invasive Glaucoma Surgeries: Systematic Review and Quality Assessment.

Glaucoma is a common blinding disease; while there is no cure, effective treatments include medications, laser, and incisional surgery. There is significant interest from patients and doctors to develop safer surgical options throughout the spectrum of disease, to minimize treatment burden in mild glaucoma patients and to minimize risk of complications in patients needing more aggressive treatment. Surgical procedures called Minimally or Micro-Invasive Glaucoma Surgery (MIGS) are growing in popularity. Eighty-seven prospective studies on MIGS were identified and assessed for quality. Most (74%) did not have a control group. Twelve of the highest quality were reviewed. MIGS procedures appeared to have fewer complications, and lowered intraocular pressure, and reduced medication use. Studies were limited by small sample size, narrow spectrum of glaucomatous disease, and/or conflicts of interest. There is a need for high quality, independently funded and performed, comparative studies on the MIGS to help make treatment decisions.

Micro-Invasive Glaucoma Surgery with the iStent inject: Impact on IOP and Medication Burden in a Real-World Setting

Background: The iStent inject is a Micro-Invasive Glaucoma Surgical (MIGS) device that has shown to reduce IOP and to be safe for glaucoma patients with fewer complications than regular surgery. Objective: To investigate, up to 15 - 20 months, the efficacy and safety of implantation of two second-generation trabecular microbypass stents in patients with or without prior glaucoma surgery. Methods: Fifty-seven eyes were implanted with the iStent inject. The population was comprised of eyes with primary open-angle glaucoma (n = 51), pseudoexfoliation glaucoma (n = 5) and ocular hypertension (n = 1). Major outcome parameters included IOP, medication needs and corrected distance visual acuity (CDVA). Follow-up time points were one day, 2 - 4 months, 9 - 14 months and 15 - 20 months. Results: The main reason to perform MIGS was IOP reduction in 68.4%, reduced number of medications due to drug intolerance in 24.6% and reduced medication due to compliance issues in 7.0% of the eyes. IOP decreased by 22.47%, from 19.40 ± 3.83 mmHg preoperatively (preop) to 15.04 ± 1.67 mmHg at 15-20 months postoperatively. IOP reduction was achieved at all follow-up time points (p < 0.001). A decrease in the number of medications was achieved in 32.1% of the patients after 15 - 20 months. Conclusions: Insertion of the iStent inject in patients with or without prior glaucoma surgery shows effective and sustained improvements in IOP with no safety concerns.

Outflow Facility Effects of 3 Schlemm’s Canal Microinvasive Glaucoma Surgery Devices

To study the effect of 3 Schlemm's canal (SC) microinvasive glaucoma surgery (MIGS) devices on outflow facility. Paired comparisons, randomized design, baseline-controlled study. Thirty-six pairs of dissected anterior segments from donated human eye bank eyes without glaucoma were studied. A baseline measurement was collected from each eye to serve as its control. Using a constant pressure perfusion method, outflow facility was measured in paired eyes from human donors. Measurements were made at perfusion pressures of 10 mmHg, 20 mmHg, 30 mmHg, and 40 mmHg. Outflow facility was measured before (baseline control) and after the implantation of an SC glaucoma drainage device or sham procedure. Three sets of experiments were carried out comparing 1 and 2 iStent Trabecular Micro-Bypass Stents and 2 iStent Inject implants with the Hydrus Microstent. Change in outflow facility from baseline or contralateral eye. After Hydrus placement, the outflow facility increased from 0.23±0.03 μl/minute per millimeter of mercury at baseline to 0.38±0.03 μl/minute per millimeter of mercury (P < 0.001). The percent increase in outflow facility was 79±21% for the Hydrus and 11±16% for the 2 iStent Inject devices, a difference that was significant (P= 0.018). Outflow facility with 1 iStent (0.38±0.07 μl/minute per millimeter of mercury) was greater than baseline (0.28±0.03 μl/minute per millimeter of mercury; P= 0.031). The 1 iStent showed a greater increase in outflow facility from baseline (0.10±0.04 μl/minute per millimeter of mercury) compared with the sham procedure (-0.08±0.05 μl/minute per millimeter of mercury; P= 0.042). No other significant differences were found. The longer the MIGS device, and thus the more SC that it dilates, the greater the outflow facility.

Current surgical management approaches for uveitic glaucoma

Glaucoma is a potentially blinding complication of uveitis.Management of uveitic glaucoma remains challenging.Vision can be partly recovered if correct diagnosis and timely treatment are given.The mechanisms of intraocular pressure (IOP) elevation include peripheral anterior synechia, pupillary block, trabecular meshwork inflammation, cyclitis and prolonged corticosteroid use.Treatment is targeted at identifying the cause of raised IOP first, followed by etiological treatment and IOP lowering medications.The indications for surgery include uncontrolled IOP despite maximum-tolerated medical management or definite optic nerve damage.Recently, selective laser trabeculopasty for steroid-induced intraocular hypertension/open angle glaucoma, CO2 laser-assisted sclerectomy surgery or micro-invasive glaucoma surgery for uveitic glaucoma have been gradually applied in clinical practice. Key words: Uveitis; Complication; Secondary glaucoma; Laser; Anti-glaucoma surgery

Refractive outcomes among glaucoma patients undergoing phacoemulsification cataract extraction with and without Kahook Dual Blade goniotomy

BackgroundGlaucoma patients undergoing phacoemulsification alone have a higher rate of refractive surprise compared to patients without glaucoma. This risk is further increased with combined filtering procedures. Indeed, there are few and conflicting reports on the effect of combined phacoemulsification and micro-invasive glaucoma surgery (MIGS). Here, we look at refractive outcomes of glaucoma patients undergoing phacoemulsification with and without Kahook Dual Blade (KDB) goniotomy.MethodsRetrospective chart review of 385 glaucomatous eyes of 281 patients, which underwent either phacoemulsification alone (n = 309) or phacoemulsification with KDB goniotomy (n = 76, phaco-KDB) at the University of Colorado. The main outcome was refractive surprise defined as the difference in target and postoperative refraction spherical equivalent greater than ±0.5 Diopter (D).ResultsRefractive surprise greater than ±0.5 D occurred in 26.3% of eyes in the phaco-KDB group and 36.2% in the phacoemulsification group (p = 0.11). Refractive surprise greater than ±1.0 D occurred in 6.6% for the phaco-KDB group and 9.7% for the phacoemulsification group (p = 0.08). There was no significant difference in risk of refractive surprise when pre-operative IOP, axial length, keratometry or performance of KDB goniotomy were assessed in univariate analyses.ConclusionThere was no difference between refractive outcomes of glaucomatous patients undergoing phacoemulsification with or without KDB goniotomy.

Gonioscopy-assisted Transluminal Trabeculotomy (GATT) is An Effective Procedure for Steroid-induced Glaucoma

Gonioscopy-assisted transluminal trabeculotomy (GATT) is a novel technique that lowers intraocular pressure (IOP) by fracturing the trabecular meshwork. In this retrospective chart review, GATT was found to be effective at lowering the intraocular pressure for steroid-induced glaucoma (SIG). GATT is a novel microinvasive glaucoma surgery that builds on traditional trabeculotomy techniques to decrease the proximal resistance of conventional outflow, and it is proposed to be an effective surgical treatment for SIG. The purpose of this study is to evaluate the efficacy of GATT for lowering the IOP in SIG. A retrospective chart review was performed of all GATT procedures performed on patients with a predominant diagnosis of steroid-induced glaucoma between March 1, 2016 and March 30,2018 at the University of Michigan. Primary outcome measures include IOP, the number of IOP-lowering medications prescribed, and the topical steroid dosing over the duration of follow-up. A total of 13 patients with steroid-induced glaucoma underwent the GATT procedure. There was a significant reduction in the mean IOP at all postoperative visits. The average IOP decreased by 16.4 (55%) to 19.5 mm Hg (63%) between 3 and 24 months postoperatively. By 24 months, all patients had a reduction in IOP of >20%. The number of glaucoma medications also decreased significantly from an average of 3.1 medications preoperatively to an average of 0.8 medications at last follow-up. The majority of patients (>67%) required continued use of steroids at all postoperative visits. The most common postoperative complication was a transient hyphema (38%). No patients required a repeat glaucoma surgery or anterior chamber washout. This small case series suggests that GATT is an effective and safe surgical technique to decrease IOP and decrease medication burden in patients with predominantly steroid-induced glaucoma. To our knowledge, this is the first study looking specifically at the efficacy of GATT for predominantly SIG.

Development of an antifibrotic drug-eluting coating for a minimally invasive implantable glaucoma microstent

Abstract Primary open angle glaucoma represents an eye disease that usually is associated with an increased intraocular pressure (IOP). Implants for micro-invasive glaucoma surgery (MIGS) are gaining importance as a promising option for IOP lowering. Currently available devices are implanted into the eye ab interno based on a clear corneal incision and drain aqueous humour into the schlemm’s canal, suprachoroidal or subconjunctival space. Fibrosis is known as a major limitation for long term success and often leads to the necessity of an additional medication or a surgical re-intervention. The current work focusses on the development of an antifibrotic drug-eluting coating for a minimally invasive implantable glaucoma microstent. Tubular microstent base bodies manufactured from a polycarbonate based silicone elastomer were spray-coated with a chloroform based mixture of the same polymer and the antifibrotic drug pirfenidone (PFD, P2116, Merck KGaA, Germany) in a polymer/drug ratio of 85/15% (w/w). Coating mass of 89 μg according to a drug loading of 1.96 μg mm-2 was aspired. Coating mass was measured using an ultramicrobalance (XP6U, Mettler-Toledo International, Inc., Switzerland). Glaucoma microstent prototypes with a drugeluting coating mass of (84 ± 19) μg (n = 12) were manufactured. Characterization by means of scanning electron microscopy (Quattro S, Thermo Fisher Scientific, FEI Deutschland GmbH, Germany) yielded a reproducible smooth surface of the coating. High performance liquid chromatography (KNAUER Wissenschaftliche Geräte GmbH, Germany) was used for analysis of drug release behaviour in 0.9% NaCl solution at 37°C. The in vitro PFDrelease is characterized by an initial burst phase of approximately 6 h followed by a more retarded release phase. The entire drug was released within 36 h (n = 3). Sterilization processing has a minor impact on drug release kinetics. Appropriate drug stability after sterilization could be proven. Future studies will focus on the antifibrotic properties of drug-eluting glaucoma microstents in animal studies.

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.

The Cost and Economics of Endoscopic Cyclophotocoagulation in the United Kingdom: A Tertiary Center Experience.

As the only microinvasive glaucoma surgery (MIGS) with a reusable component, the cost per procedure of endoscopic cyclophotocoagulation (ECP) diminishes with each successive use. We present a cost comparison of ECP with other MIGS devices, based on our clinical practice. ECP delivers diode laser via a reusable probe to the ciliary processes under direct visualization. The aim of our study is to evaluate the direct cost of ECP based on a retrospective review of cases and compare the cost per procedure with other MIGS devices. We conducted a retrospective review of ECP procedures performed at St Thomas' Hospital over 4.5 years. The cost of the ECP endoscope and diode laser consoles, reusable probes, and maintenance contracts were obtained from the hospital procurement log. The on-site Central Sterile Services Department was contacted for probe sterilization and repackaging costs. The cost per device for ECP and commonly performed MIGS procedures were obtained from the product specialists of each company. A total of 332 procedures were performed using 37 ECP probes during the study period. Each reusable ECP laser probe was found to give an average of 8.97 laser treatments. The cost per procedure decreased over the course of 4.5 years from £819.43 for the first 42 cases to £341.50 after 332 cases. Compared with other MIGS devices, the cost per procedure of ECP after 100 procedures is second lowest to the Kahook Dual Blade and reduces with each successive procedure performed. The ability to reuse each ECP probe significantly lowers the cost per procedure compared with other MIGS devices in the United Kingdom. The cost per procedure continues to reduce with each successive procedure.

Микроинвазивная дренажная хирургия глаукомы

Микроинвазивная дренажная хирургия глаукомы

Combined phacoemulsification and microinvasive glaucoma surgery in comparison to phacoemulsification alone for open angle glaucoma.

Microinvasive glaucoma surgery (MIGS) combined with phacoemulsification is increasingly utilised in glaucoma management. To describe the postoperative outcomes of phacoemulsification alone compared to combined phacoemulsification and iStent (Glaukos, San Clemente, CA) or Hydrus (Ivantis, Irvine, CA) for open angle glaucoma. Retrospective single surgeon comparative case series in a private practice setting. A total of 297 eyes in 190 patients (M:F = 85:105) were included consecutively from March 2011 to June 2017 with the data analysed using linear mixed models. Main outcome measures were intraocular pressure(IOP) and number of medications. By 6 months, all groups showed a reduction in IOP, with the combined iStent group by 4.2 mm Hg and the combined Hydrus group by 4.5 mm Hg, and this trend was sustained with follow-up to two years. All groups also showed a reduction in number of medications, with the phacoemulsification alone cases by 0.3, the combined iStent group by 0.7 and the combined Hydrus group by 1.1 medications. Both the combined surgeries had sustained reduction of number of medications with follow-up to 2 years. Postoperative complications from MIGS device insertion were uncommon and all resolved by one month. The combination of phacoemulsification and a MIGS device in open angle glaucoma patients reduced the intraocular pressure and the number of medications by the first postoperative month and had longer-term effects at 2 years follow-up. If the device is inserted without intraoperative complication, the rate of significant short-term risks are low.

Glaucoma surgery preferences when the surgeon adopts the role of the patient.

To survey the members of the American Glaucoma Society (AGS) to determine which glaucoma procedures they would prefer to have performed on themselves. We distributed an anonymous, electronic survey via the AGS listserv. The participants were asked to adopt the role of a patient with primary open angle glaucoma with progressive visual field loss in need of glaucoma surgery. Three preoperative intraocular pressure (IOP) levels were provided (>26 mmHg, 21-26 mmHg, and <21 mmHg), and the participants were asked to choose a glaucoma procedure they would prefer performed on themselves under each preoperative IOP levels from a list of fifteen procedures. Out of 289 responses (representing 27.4% of active and provisional AGS members), the most preferred procedures were ab interno trabeculotomy (20.3%), Xen gel stent (18.6%), iStent with two devices (14.3%) and traditional trabeculectomy augmented with mitomycin C (14.1%). 17.6% and 6.9% of participants preferred a trabeculectomy performed or a glaucoma drainage device (GDD) implanted on themselves, which is a lower than what would be offered to a hypothetical patient. Significant proportions of participants prefer non-bleb forming or conjunctiva-sparing procedures, even with low preoperative IOP levels. Older participants were more likely to prefer traditional trabeculectomy and having a single procedure across all levels of preoperative IOP. The majority of AGS participants in the survey would prefer micro-invasive glaucoma surgery over traditional trabeculectomy or a GDD performed on themselves as a primary glaucoma procedure, and most would prefer non-bleb forming and conjunctiva-sparing procedures.

A Prospective Randomized Trial Comparing Hydrus and iStent Microinvasive Glaucoma Surgery Implants for Standalone Treatment of Open-Angle Glaucoma: The COMPARE Study

To compare the efficacy of different microinvasive glaucoma surgery (MIGS) devices for reducing intraocular pressure (IOP) and medications in open-angle glaucoma (OAG). Prospective, multicenter, randomized clinical trial. One hundred fifty-two eyes from 152 patients aged 45 to 84 years with OAG, Shaffer angle grade III-IV, best-corrected visual acuity (BCVA) 20/30 or better, and IOP 23 to 39 mmHg after washout of all hypotensive medications. Eyes with secondary glaucoma other than pseudoexfoliative or pigmentary glaucoma, angle closure, previous incisional glaucoma surgery, or any significant ocular pathology other than glaucoma were excluded. Study eyes were randomized 1:1 to standalone MIGS consisting of either 1 Hydrus Microstent (Ivantis, Inc, Irvine, CA) or 2 iStent Trabecular Micro Bypass devices (Glaukos Inc, San Clemente, CA). Follow-up was performed 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. Within-group and between-group differences in IOP and medications at 12 months and complete surgical success defined as freedom from repeat glaucoma surgery, IOP 18 mmHg or less, and no glaucoma medications. Safety measures included the frequency of surgical complications, changes in visual acuity, slit-lamp findings, and adverse events. Study groups were well matched for baseline demographics, glaucoma status, medication use, and baseline IOP. Twelve-month follow-up was completed in 148 of 152 randomized subjects (97.3%). At 12 months, the Hydrus had a greater rate of complete surgical success (P < 0.001) and reduced medication use (difference= -0.6 medications, P= 0.004). More Hydrus subjects were medication free at 12 months (difference= 22.6% P= 0.0057). Secondary glaucoma surgery was performed in 2 eyes in the 2-iStent group (3.9%) and in none of the Hydrus eyes. Two eyes in the Hydrus group and 1 in the 2-iStent group had BCVA loss of ≥2 lines. Standalone MIGS in OAG with the Hydrus resulted in a higher surgical success rate andfewermedications compared with the 2-iStent procedure. The 2 MIGS devices have similar safety profiles.

Anterior Chamber Angle, Volume, and Depth in a Normative Cohort—A Retrospective Cross-Sectional Study

ABSTRACTPurpose: The purpose of the study was to determine the distribution of the anterior chamber angle (ACA) within a population-based study sample in Germany and to find correlations between age, sphere, and biometric parameters of the anterior chamber.Patients and Methods: A total of 500 eyes, approximately 100 eyes per decade starting with patient age of 20 years, of 463 patients with an average age of 45.2 ± 14.1 (±values subsequent represent standard deviation) years without any known history of ocular diseases, surgery, or optic nerve head excavation or hypoplasia were included.ACAs, volume, and depth were correlated to age and sphere. Scheimpflug images (Pentacam, Oculus) with automatically measured ACAs were compared to manually measured angles (Bland Altman analysis) in this healthy population.Results: The mean manually measured ACA was 26.5° ± 3.9°; the highest average angle was found in the temporal position with 28.1° ± 4.9°, while the lowest average angle was found in nasal superior position with 25.7° ± 4.7°.Statistical analysis showed an average difference of +11.4° nasal and +12.1° temporal between the automatic measurements and the manually measured angles (P < 0.01). The analysis also revealed an independent inverted correlation between age (correlation coefficient between −0.28 and −0.38) and sphere (correlation coefficient between −0.44 and −0.51) of the participants and the anterior chamber volume, angle, and anterior chamber depth (P < 0.01 for all correlations).Conclusion: The ACA width manually measured is considerably less compared to automated imaging and formerly reported values. There is a significant difference in the ACA dependent on the position of measurement (superior, nasal, inferior, and temporal) with the average angle being inversely correlated to age and sphere.Abbreviations: AC: anterior chamber ACA: anterior chamber angle ACV: anterior chamber volume ACD: anterior chamber depth AAC: acute angle closure OAG: open-angle glaucoma OCT: optical coherence tomography ACG: angle-closure glaucoma MIGS: microinvasive glaucoma surgery PACS: primary angle-closure suspects

Episcleral Venous Fluid Wave in the Living Human Eye Adjacent to Microinvasive Glaucoma Surgery (MIGS) Supports Laboratory Research: Outflow is Limited Circumferentially, Conserved Distally, and Favored Inferonasally.

The purpose of this study was to describe downstream patterns of outflow with the episcleral venous fluid wave (EVFW) in the living human eye adjacent to microinvasive glaucoma surgery (MIGS) and determine if the EVFW supports existing ex-vivo laboratory outflow research. Retrospective, noncomparative case series. A total of 10 eyes of 10 patients who underwent phaco-Trabectome and 10 eyes of 10 patients who underwent phaco-iStent consecutively at Glaucoma Associates of Texas for cataract and uncontrolled glaucoma who demonstrated an episcleral wave. The EVFW was visualized and recorded during irrigation and aspiration. To describe the hydrodynamic properties of the fluid wave, its degrees, extent, and characteristics were measured with a protractor in Photoshop. The incised Trabectome arc produced adjacent episcleral blanching of 134±11 degrees (range, 112 to 150 degrees) with an additional 54 degrees of marginal recruitment (41 degrees inferonasal plus 13 degrees superonasal) adjacent to the ends of the Trabectome incision. The mean episcleral blanch for the iStent was 51±19 degrees (range, 19 to 90 degrees), comprised of 29 degrees inferonasal plus 22 degrees superonasal. Downstream episcleral flow in the living human eye adjacent to the iStent is variable and mainly confined to 2 clock hours indicating a lack of significant circumferential flow in glaucomatous eyes. Flow distal to the Trabectome site encompasses the Trabectome incisional arc with an additional 2 clock hours of lateral fluid wave favoring the inferonasal over superonasal quadrant 3 to 1. These in-vivo findings made visible with MIGS, corroborate recent in-vivo and long-standing ex-vivo laboratory research that outflow is largely segmented, favored inferonasally and conserved distally.