iStent trabecular micro-bypass stent for open-angle glaucoma

Consistency in Standalone Canaloplasty Outcomes Using the iTrack Microcatheter

Purpose

To study the consistency in outcomes of standalone canaloplasty performed via an ab-interno surgical technique in reducing intraocular pressure (IOP) and number of medications in uncontrolled open-angle glaucoma (OAG) eyes over a 12-month period.

Methods

This retrospective multicenter case series included patients who underwent standalone canaloplasty via an ab-interno surgical technique using the iTrack microcatheter (Nova Eye, Inc., Fremont, USA) and had preoperative uncontrolled OAG (IOP≥18mmHg) along with no previous glaucoma surgery. The iTrack microcatheter is used to circumnavigate 360° and viscodilate Schlemm's canal. Consistency of IOP and medications reduction on an eye-by-eye basis were evaluated to understand the outcomes in each single eye.

Results

Sixty-four eyes of 60 patients (age 71.5±13.4 years) were included. Six eyes (9%) that underwent additional glaucoma surgery were considered a failure and were subsequently excluded from analysis. At 12 months, IOP was reduced in 57 of the 58 (89%) remaining eyes; one eye had the same IOP with a reduced number of medications. Of the 57/58 eyes with a reduced IOP: 44 eyes (69%) required fewer medications; 12 eyes (19%) required the same number of medications. Of these 58 eyes, 78% of eyes had a ≥20% reduction in IOP compared to baseline; 69% eyes had a postoperative IOP ≤15 mmHg, and 86% eyes ≤18 mmHg at 12 months. Forty percent of the eyes were medication-free at 12 months compared to none at baseline.

Conclusion

Canaloplasty performed via an ab-interno surgical technique as a standalone procedure consistently reduced IOP and glaucoma medications in almost all eyes.

Development and material characteristics of glaucoma surgical implants

Background

Glaucoma is the leading cause of irreversible blindness worldwide. The reduction of intraocular pressure has proved to be the only factor which can be modified in the treatment, and surgical management is one of the important methods for the treatment of glaucoma patients.

Main text

In order to increase aqueous humor outflow and further reduce intraocular pressure, various drainage implants have been designed and applied in clinical practice. From initial Molteno, Baerveldt and Ahmed glaucoma implants to the Ahmed ClearPath device, Paul glaucoma implant, EX-PRESS and the eyeWatch implant, to iStent, Hydrus, XEN, PreserFlo, Cypass, SOLX Gold Shunt, etc., glaucoma surgical implants are currently undergoing a massive transformation on their structures and performances. Multitudinous materials have been used to produce these implants, from original silicone and porous polyethylene, to gelatin, stainless steel, SIBS, titanium, nitinol and even 24-carat gold. Moreover, the material geometry, size, rigidity, biocompatibility and mechanism (valved versus nonvalved) among these implants are markedly different. In this review, we discussed the development and material characteristics of both conventional glaucoma drainage devices and more recent implants, such as the eyeWatch and the new minimally invasive glaucoma surgery (MIGS) devices.

Conclusions

Although different in design and materials, these delicate glaucoma surgical implants have widely expanded the glaucoma surgical methods, and improved the success rate and safety of glaucoma surgery significantly. However, all of these glaucoma surgical implants have various limitations and should be used for different glaucoma patients at different conditions.

Microstent Implantation with Phacoemulsification Versus Phacoemulsification Alone for Patients with Open Angle Glaucoma: A Systematic Review and Meta-Analysis of Randomised Clinical Trials

PURPOSES

The purpose of this meta-analysis is to systematically compare the IOP-lowering effect of different microstents combined with phacoemulsification versus phacoemulsification for patients with OAG and cataract.

METHODS

This work was done through the data searched from PubMed, EMBASE, and the Cochrane Library. The Cochrane Handbook was also used to evaluate the quality of the included studies. In addition, this meta-analysis was performed using Revman 5.4 software.

RESULTS

A total of 8 randomized controlled trials (RCTs) were included. Compared with phacoemulsification alone, microstent implantation with phacoemulsification resulted in significant reduction in the postoperative IOP (MD = -1.66, 95%CI: [-2.25 to -1.06]). Patients with medication free and patients with beyond 20% IOP reduction were significantly increased in the microstent implantation with phacoemulsification group compared with phacoemulsification alone group (RR = 1.54, 95%CI: [1.34 to 1.77]; RR = 1.34, 95%CI: [1.24 to 1.45]).

CONCLUSION

Both microstent implantation with concurrent phacoemulsification and phacoemulsification alone result in a significant reduction in IOP. In terms of both reductions, microstent implantation with phacoemulsification significantly outperforms phacoemulsification alone.

Corneal Endothelial Cell Loss in Patients After Minimally Invasive Glaucoma Surgery: Current Perspectives

Minimally invasive glaucoma surgery (MIGS) is a rapidly expanding category of surgical glaucoma treatment options that offer a superior safety profile compared with traditional approaches for reducing intraocular pressure. However, MIGS may cause corneal endothelial cell loss; therefore, it has been receiving increasing attention. This systematic review aimed to evaluate and compare the rate and degree of corneal endothelial loss after MIGS. First, this paper presents an overview of the theoretical effectiveness of MIGS, the fundamental aspects regarding the roles of endothelial cells, and the effect of cataract surgery on the quality and count of endothelial cells. Further, we detail the various surgical techniques involved in MIGS, the development of these techniques over the time, and clinical aspects to consider with respect to the endothelial cell count. We discuss in detail the COMPASS-XT study, which was based on data collected over 5 years, reported that withdrawal of the CyPass Micro-Stent (Alcon Laboratories) yielded increased corneal endothelial cell loss. Generally, MIGS procedures are considered safe, with the incidence of complications ranging from 1% to 20% depending on the surgery type; however, there is still need for studies with longer follow-up. Thus, an adequate count of endothelial cells in the central cornea portion is recommended as necessary for candidate patients for MIGS.

Anterior Segment Optical Coherence Tomography Angiography Following Trabecular Bypass Minimally Invasive Glaucoma Surgery

Objective

To assess anterior segment optical coherence tomography angiography (AS-OCTA) imaging of the episcleral vessels before and after trabecular bypass minimally invasive glaucoma surgery (MIGS).

Design

A prospective, clinical, single-centre, single-arm pilot feasibility study conducted at National University Hospital, Singapore.

Subjects

Patients with primary glaucomatous optic neuropathy undergoing Hydrus Microstent (Ivantis Inc., Irvine, CA, USA) implantation, who require at least one intra-ocular pressure-lowering medication. One or two eyes per patient may be enrolled.

Methods

We performed AS-OCTA (Nidek RS-3000 Advance 2, Gamagori, Japan) pre- and up to 6 months post-MIGS implantation using a standard protocol in all cornealimbal quadrants, to derive episcleral vessel densities (VD) using a previously described technique.

Main Outcome Measures

Episcleral VD pre- and post-surgery, in sectors with and without the implant.

Results

We obtained serial AS-OCTA images in 25 eyes undergoing MIGS implantation (23 subjects, mean age 70.3 ± 1.5, 61% female) with mean preoperative intraocular pressure (IOP) of 15.5 mmHg ± 4.0. We observed reductions in postoperative episcleral VD compared to preoperative VD at month 1 (mean difference −3.2, p = 0.001), month 3 (mean difference −2.94, p = 0.004) and month 6 (mean difference −2.19, p = 0.039) in sectors with implants (overall 6 month follow-up, p = 0.011). No significant changes were detected in episcleral VD in the sectors without implants (p = 0.910).

Conclusion

In our pilot study, AS-OCTA was able to detect changes in the episcleral VD following trabecular bypass MIGS, which may be a useful modality to evaluate surgical outcomes if validated in future studies.

Effect of postoperative corticosteroids on surgical outcome and aqueous autotaxin following combined cataract and microhook ab interno trabeculotomy

To evaluate the effect of postoperative corticosteroids on surgical outcome and autotaxin (ATX) levels after microhook ab interno trabeculotomy combined with cataract surgery (μLOT-CS), prospective, consecutive non-randomized case series comparing outcomes of 30 eyes with primary open angle glaucoma was performed. The aqueous ATX, intraocular pressure (IOP) and glaucoma medications were monitored for 3 months postoperatively. An in-vivo mouse μLOT model was generated. In vitro, ATX and fibrotic changes induced by dexamethasone (Dex) treatment following scratch (S) in cultured human trabecular meshwork (hTM) cells were assessed by immunofluorescence, immunoenzymatic assay, and RT-qPCR. Postoperative ATX at 1 week and the number of antiglaucoma medications at 3 months were significantly lower in non-steroid group, and steroid use was the only variable significantly associated with postoperative medications at 3 months in multiregression analyses. In vitro, ATX activity was significantly upregulated in the Dex + S group, and αSMA was significantly upregulated in the Dex and Dex + S groups. Fibronectin and COL1A1 were significantly upregulated in the S group. μLOT-CS decreased IOP and medications in the overall cohort, and non-use of postoperative steroids resulted in a smaller number of postoperative medications. Limiting postoperative steroids in μLOT may minimize IOP elevation and postoperative fibrosis.

Impact of iStent Micro-Bypass Shunt on Medicare Part B Glaucoma Surgical Expenditure

PURPOSE

To examine the impact of the iStent (Glaukos) on the recent glaucoma surgical expenditure for Medicare Part B beneficiaries.

DESIGN

Retrospective, observational, population-based analysis.

PARTICIPANTS

All applicable cases in the Centers for Medicare and Medicaid Services Part B Summary Data Files.

METHODS

The Part B National Summary Data Files from 2007 to 2017 were obtained through the Centers for Medicare and Medicaid Services. Glaucoma surgical procedures, including trabeculectomy, glaucoma drainage implants (GDIs), and select minimally invasive glaucoma surgeries (MIGS) including the iStent, were queried from the database using Current Procedural Terminology (CPT) codes. We used Chow's test to confirm significant changes in expenditure trajectories. We built a mixed-effects regression model to examine the effect of demographic factors on each state's iStent adoption speed.

MAIN OUTCOME MEASURES

Proportion of iStent in total glaucoma surgical spending for individual states for each year.

RESULTS

Total Medicare part B payment for the selected glaucoma procedures increased from $52.0 million in 2007 to $179.9 million in 2017. The percentage for trabeculectomy and GDIs decreased from 92.3% to 21.2%. Conversely, the iStent, approved by the Food and Drug Administration in 2012, increased to represent 57.9% of total payment by 2017. There were significant changes in the slope of glaucoma surgical Medicare payment (P < 0.00001) and iStent payment (P < 0.0001) trajectories in 2012. Mixed-effect regression analysis showed a wide range among the states' rates of increase in iStent proportion between 2012 and 2017 (range, 5.12%-14.54% per year). Higher male proportion in the population was associated with faster increases in iStent proportions (12.4% per 5% increase in male proportion, 95% confidence interval [CI], 4.3-20.5, P = 0.003). Higher median age of the population was associated with slower increases (-3.6% per 1-year increase in median age, 95% CI, -0.4 to -6.8, P = 0.026).

CONCLUSIONS

Increasing payment for the iStent represents the majority of the increase in glaucoma surgical spending in the recent decade. Male gender and age significantly affect the state-wise speed of adoption for the iStent. The impact of the iStent on the comprehensive glaucoma Medicare expenditure in the same time period warrants further study.

Minimally Invasive Glaucoma Surgery: A Budget Impact Analysis and Evaluation of Patients' Experiences, Preferences, and Values

BACKGROUND

Glaucoma is a condition that causes progressive damage to the optic nerve, which can lead to visual impairment and irreversible blindness. There is a spectrum of current treatments for glaucoma that aim to reduce intraocular pressure (IOP), including pharmacotherapy (eye drops), laser therapy, and the more invasive option of filtration surgery. A new class of treatments called minimally invasive glaucoma surgery (MIGS) may reduce IOP and offer a better safety profile than more invasive procedures. We conducted a budget impact analysis of MIGS for adults with glaucoma from the perspective of the Ontario Ministry of Health and Long-Term Care. We also conducted interviews with people with glaucoma and family members of people with glaucoma to determine patient preferences and values surrounding glaucoma and its treatment options, including MIGS. We completed this work to complement a health technology assessment conducted in collaboration with the Canadian Agency for Drugs and Technologies in Health (CADTH).

METHODS

We analyzed the budget impact of publicly funding MIGS in adults with glaucoma in Ontario. We derived costs from the collaborative health technology assessment.¹ We assumed MIGS may be used in three subgroups: (1) MIGS in combination with cataract surgery as a replacement for cataract surgery alone in people with mild to moderate glaucoma; (2) MIGS alone as a replacement for other glaucoma treatments in people with mild to moderate glaucoma; and (3) MIGS (alone or in combination with cataract surgery) to replace filtration surgery (alone or in combination with cataract surgery) in people with advanced to severe glaucoma. We estimated the budget impact over 5 years for two possible uptake scenarios: a slow rate of uptake and a fast rate of uptake. To contextualize the lived experience of glaucoma and treatments for glaucoma, we also interviewed people with glaucoma and family members of people with glaucoma, some of whom had experience with surgical procedures such as MIGS and some of whom did not.

RESULTS

Assuming a slow uptake scenario, the annual budget impact of publicly funding MIGS in Ontario over the next 5 years ranges from $1 million in year 1 to $18 million in year 5. Assuming a fast uptake scenario, the annual budget impact of publicly funding MIGS in Ontario over the next 5 years ranges from $6 million in year 1 to $70 million in year 5. The budget impact varies depending on the proportion of people in each of the three subgroups described above. Introducing a new MIGS billing code may reduce the overall expenditures. Interview participants felt that less invasive surgical procedures, such as MIGS, could control glaucoma progression with minimal side effects and recovery time needed.

CONCLUSIONS

We estimate that publicly funding MIGS in Ontario would result in additional costs over the next 5 years; however, this may depend on the populations using MIGS and if uptake is restricted or controlled. For the people with glaucoma we spoke with, avoiding blindness was their paramount concern, and MIGS was perceived as an effective treatment option with minimal side effects and recovery time required.

Cellular and cytoskeletal alterations of scleral fibroblasts in response to glucocorticoid steroids

Steroid-induced ocular hypertension can be seen even after trabecular meshwork (TM) bypass/ablation. Thus, the purpose was to investigate steroid-response in cells distal to the TM by using primary scleral fibroblasts. Primary scleral cell cultures were generated using mid-depth scleral wedges from human donor corneo-scleral rims (n = 5) after corneal transplantation. Cells were treated with dexamethasone (DEX; 100 nM) and compared to media (MED)/vehicle (DMSO) controls. Cell size, shape, and migration were studied using the IncuCyte Live-Cell Analysis System. Cytoskeleton was compared using Alexa Fluor-568 Phalloidin and senescence tested by evaluating beta-galactosidase. Western blot comparison was performed for α-SMA, FKBP-51, fibronectin, phospho-myosin light chain, and myocilin. Scleral fibroblasts upregulated FKBP-51 in response to DEX indicating the existence of steroid-responsive pathways. Compared to controls, DEX-treated cells proliferated slower (~50%; p < 0.01-0.02), grew larger (~1.3-fold; p < 0.001), and migrated less (p = 0.01-0.006). Alexa Fluor 568 Phalloidin actin stress fiber labeling was more diffuse in DEX-treated cells (p = 0.001-0.004). DEX-treated cells showed more senescence compared to controls (~1.7-fold; p = 0.01-0.02). However, DEX-treated cells did not show increased cross-linked actin network formation or elevated myocilin/fibronectin/α-SMA/phospho-myosin light chain protein expression. For all parameters, MED- and DMSO-treated control cells were not significantly different. Primary scleral fibroblasts, grown from tissue collected immediately distal to the TM, demonstrated scleral-response behaviors that were similar to, but not identical with, classic TM steroid-response. Further study is needed to understand how these scleral cellular alterations may contribute to steroid-response IOP elevation after TM bypass/ablation surgery.

Ab interno canaloplasty combined with trabecular bypass stenting in eyes with primary open-angle glaucoma

Purpose

Evaluate outcomes of trabecular meshwork (TM) bypass (iStent^® GTS100) with cataract extraction (CE) and TM-bypass + ab interno canaloplasty (CP) (VISCO360^®) with CE in patients with primary open-angle glaucoma (POAG).

Setting

Private surgical center for a comprehensive ophthalmology practice

Design

Retrospective analysis of 186 eyes from 130 consecutive patients with 6 months follow-up.

Methods

Eligible eyes had POAG, indicated for CE, and had received CE + TM-bypass or CE + TM-bypass + CP. Exclusions: glaucomas not POAG, SLT within 6 months, or previous ALT. IOP, visual acuity, and medication use assessed at baseline, months 1, 3, and 6. Endpoints were mean reduction in IOP from baseline at 6 months, proportion with IOP reduction at 6 months of ≥20% and IOP <18 mmHg on same or fewer medications, mean medication reduction, and proportion medication independent.

Results

Eighty-six eyes comprised the CE + TM-bypass + CP group; 100 eyes in the CE + TM-bypass group. At 6 months: mean IOP reduction was 2.9±3.6 mmHg for CE + TM-bypass + CP and 1.7±3.1 mmHg for CE + TM-bypass group (P<0.05); the proportion with IOP reduction of ≥20% and an IOP <18 mmHg on the same or fewer medications was 46% for CE + TM-bypass + CP and 35% for CE + TM-bypass; for both CE + TM-bypass + CP and CE + TM-bypass, mean number of medications was decreased (0.9 and 0.7, P<0.0001) with 56% and 48% off all medication. The most common AE were inflammation (6%) for CE + TM-bypass + CP group and VA loss (8%) for CE + TM-bypass.

Conclusion

At six months, a greater proportion of CE + TM-bypass + CP patients achieved IOP reduction of ≥20% and an IOP <18 mmHg on the same or fewer medications than for TM-bypass + CE.

Refractive outcomes after trabecular microbypass stent with cataract extraction in open-angle glaucoma

PURPOSE

To evaluate the impact of trabecular microbypass stents combined with cataract surgery on refractive outcomes in patients with open-angle glaucoma (OAG).

SETTING

Private practice, Sioux Falls, South Dakota, USA.

DESIGN

Retrospective, comparative case series.

METHODS

Eyes with OAG had implantation of trabecular microbypass stents with concomitant cataract surgery. The unmatched control group comprised eyes that underwent only cataract extraction. Data were collected preoperatively and postoperatively for 6 months. Data included spherical equivalent (SE), astigmatic error, intraocular pressure (IOP), and number of glaucoma medications.

RESULTS

The series included 76 consecutive OAG eyes with combined cataract plus trabecular microbypass stent and 50 consecutive non-OAG eyes with cataract surgery only. SE outcomes were equivalent between the groups (P<0.001). For the combined and cataract-only groups respectively, 46% vs 52% had SEs within 0.25 D of the target, 80% vs 80% within 0.50 D, and 95% vs 94% within 1.00 D. Astigmatism outcomes did not significantly differ between the groups (P>0.05). As for magnitude of astigmatism in the combined and cataract only groups respectively, 51% vs 32% were within 0.5 D, 75% vs 66% within 1.0 D, 87% vs 82% within 1.5 D, and 89% vs 94% within 2.0 D. In the OAG combined-surgery group, mean intraocular pressure reduction was 3.4 mmHg (P<0.0001) at 1 month postoperatively, 4.0 mmHg (P<0.0001) at 3 months, and 3.4 mmHg (P<0.01) at 6 months. Mean decrease in number of glaucoma medications was 0.4 (P<0.05) at 1 month, 0.7 (p<0.0001) at 3 months, and 0.9 (P<0.001) at 6 months.

CONCLUSION

The results of this study suggest the trabecular microbypass stent is a refractively neutral device.

The long-term outcome of trabeculotomy: comparison with filtering surgery in Japan

Background

To investigate the long-term outcome of trabeculotomy and to compare it with that of trabeculectomy.

Methods

We retrospectively reviewed the medical records of patients who had undergone standalone trabeculotomy. Inclusion criteria included a follow-up period of at least 6 years, availability of reliable static visual field results, etc. Age- and preoperative intraocular pressure -matched trabeculectomy cases served as controls. A Kaplan-Meier analysis was employed as a measure of surgical success. Additional clinical factors were also analyzed.

Results

Twenty-five eyes of 25 trabeculotomy patients and 20 eyes of 20 trabeculectomy patients with a mean postoperative follow-up period of 8.0 years were selected. The Kaplan-Meier analysis estimated that the success probability defined as intraocular pressure < 16 mmHg was 44.0 ± 9.9% and 75.0 ± 9.7% at 6 years for trabeculotomy and trabeculectomy, respectively. The final mean deviation significantly progressed in trabeculotomy cases in Central 30–2 programs of the Humphrey Field Analyzer (P = 0.025). Patient characteristics and postoperative clinical data were analyzed by Mann-Whitney’s U test and Wilcoxon signed-rank test.

Conclusions

While trabeculotomy was inferior to trabeculectomy in terms of intraocular pressure control and visual field stability in our series, surgical indications should always be determined on an individual basis, pending further research.

Systematic Literature Review of Clinical and Economic Outcomes of Micro-Invasive Glaucoma Surgery (MIGS) in Primary Open-Angle Glaucoma

INTRODUCTION

Primary open-angle glaucoma is estimated to affect 3% of the population aged 40-80 years. Trabeculectomy is considered the gold standard in surgical management of glaucoma; however, it is a technically complex procedure that may result in a range of adverse outcomes. Device-augmented, minimally invasive procedures (micro-invasive glaucoma surgeries, MIGS) have been developed aiming for safer and less invasive intraocular pressure (IOP) reduction compared with traditional surgery.

METHODS

This paper presents results from a systematic literature review conducted in accordance with National Institute for Health and Care Excellence requirements for the Medical Technology Evaluation Programme via multiple databases from 2005 to 2016. For clinical outcomes, randomized clinical trials (RCTs) comparing MIGS with trabeculectomy or other therapies, observational studies, and other non-RCTs were included. Clinical outcomes reviewed were the change from baseline in mean IOP levels and change in topical glaucoma medication. Safety was assessed by reported harm and adverse events. For economic evidence, trials on cost-effectiveness, cost-utility, cost-benefit, cost-consequences, cost-minimization, cost of illness, and specific procedure costs were included. Risk of bias was assessed for clinical studies using the Cochrane Risk of Bias tool.

RESULTS

A total of nine RCTs (seven iStents®, one Hydrus®, and one CyPass®), seven non-RCTs (three iStent®, three CyPass®, and one Hydrus®), and 23 economic studies were analyzed. While various forms of trabeculectomy can achieve postoperative IOP of between 11.0 and 13.0 mmHg, MIGS devices described in this review were typically associated with higher postoperative IOP levels. In addition, MIGS devices may result in increased hypotony rates or bleb needling in subconjunctival placed devices, requiring additional medical resources to manage. There is limited available evidence on the cost-effectiveness of MIGS and therefore it remains unclear whether the cost of using MIGS is outweighed by cost savings through decreased medication and need for further interventions.

CONCLUSION

Larger randomized trials and real-world observational studies are needed for MIGS devices to better assess clinical and economic effectiveness. Given the shortage of published data and increasing use of such procedures, living systematic reviews may help to provide ongoing and timely evidence-based direction for clinicians and decision makers. This review highlights the current unmet need for treatments that are easy to implement and reduce long-term IOP levels without increasing postoperative aftercare and cost.

FUNDING

Santen GmbH, Germany.

Implantation of trabecular micro-bypass stent using a novel "landing strip" technique

AIM

To describe a novel technique of creating a landing strip within the trabecular meshwork to guide trabecular micro-bypass stent (iStent) implantation in patients who underwent phacoemulsification.

METHODS

Thirty-four eyes from 30 patients who underwent iStent implantation after phacoemulsification from May 2014 to February 2015 were included in our retrospective study. All iStents were implanted via the "landing strip" technique. A 25-gauge microvitreoretinal blade was used to bisect the trabecular meshwork to less than 1 clock-hour, effectively creating a landing strip. The iStent applicator was pressed along the landing strip and then the stent was released into the trabecular meshwork.

RESULTS

Of the 34 eyes with iStent implantation, 27 (79.4%) eyes had primary open-angle glaucoma, 6 (17.6%) eyes had pseudoexfoliation glaucoma, and 1 (2.9%) eye had ocular hypertension. At 6-month follow-up (n=17), the mean number of hypotensive medications decreased from 2.2±1.2 at baseline to 0.8±1.3 (P=0.05) and mean intraocular pressure decreased from 19.7±4.1 mm Hg at baseline to 16.7±2.1 mm Hg (P=0.58). Two eyes (5.9%) required subsequent trabeculectomy.

CONCLUSION

The "landing strip" technique appears to be an effective way to assist with iStent implantation.

Is there a change in the quality of life comparing the micro-invasive glaucoma surgery (MIGS) and the filtration technique trabeculectomy in glaucoma patients?

PURPOSE

This study was conducted to assess the impact on the Quality of Life (QOL) of micro-invasive glaucoma surgery (MIGS: iStent, Trabectome) and a penetrating technique such as Trabeculectomy (TE).

METHODS

This study evaluated 88 eyes of 88 open angle glaucoma patients undergoing glaucoma surgery: 43 (mean age 72.8 ± 8.8y, female 59.5 %, male 40.5 %) Trabectome (NeoMedix, Inc., Tustin, CA, USA), 20 (mean age 68.6 ± 16.4y, female 60 %, male 40 %) iStent (Glaucos Corporation, Laguna Hills, CA, USA), and 25 TE patients (mean age 74.2 ± 9.1y female 58.3 %, male 41.7 %). The National Eye Institute-Visual Functioning Questionnaire (VFQ-25) survey was used to assess the QOL at 6 months post surgery. The following 12 QOL parameters were evaluated: general health, ocular pain, general vision, near and distance activities, mental health, social functioning, role difficulties, dependency, driving, color vision, and peripheral vision. Intraocular pressure (IOP), number of topical medications, and visual acuity (VA) were examined preoperatively, 1 day, 6 weeks, 3 months, and 6 months post surgery. Statistical data were calculated using SPSS (v20.0, SPSS, Inc.).

RESULTS

There was no significant difference between TE and MIGS in the quality of life 6 months postoperatively. IOP was significantly lower in TE compared to MIGS at 6 weeks and 3 months postoperatively (p = 0.046 and p = 0.046). Number of medications was significantly decreased in TE compared to MIGS (p < 0.001). A significant difference in VA between TE and MIGS could be assessed at day 1 post-op (p = 0.011).

CONCLUSION

In this study cohort, the QOL can be maintained by all three surgical techniques. Patients, however, need lower numbers of topical medication in TE, which would impact QOL even though it is not included in the NEI-VFQ-25. The decision of the most appropriate surgical technique should be made by including single QOL categories, IOP and glaucoma medication outcome.

Contralateral eye comparison study in MICS & MIGS: Trabectome® vs. iStent inject®

PURPOSE

To compare the safety and efficacy profile after combined micro-incision cataract surgery (MICS) and micro-invasive glaucoma surgery (MIGS) with the ab interno trabeculectomy (Trabectome®) in one eye versus two iStent® inject devices in the contralateral eye in patients with open-angle glaucoma (OAG) and cataract.

METHODS

This retrospective, intraindividual eye comparison study included 27 patients (54 eyes) who were treated with combined MICS and ab interno trabeculectomy (group I, Trabectome®) in one eye and two iStent® inject devices (group II, GTS 400) in the fellow eye. Primary outcome measures included intraocular pressure (IOP) and glaucoma medication after 6 weeks, 3, 6, and 12 months follow-up. Secondary outcome measures were number of postoperative interventions, complications, and best-corrected visual acuity (BCVA).

RESULTS

Mean preoperative IOP decreased from 22.3 ± 3.7 mmHg in group I and 21.3 ± 4.1 mmHg in group II to 15.6 ± 3.6 mmHg for Trabectome (p < 0.001) and 14.0 ± 2.3 mmHg for iStent inject (p < 0.001) at 12 months after surgery without a significant difference between the two groups (p > 0.05). No vision-threatening complications such as choroidal effusion, choroidal hemorrhage, or infection occurred. In each group trabeculectomy had to be performed in two eyes due to insufficient IOP lowering effect.

CONCLUSIONS

Ab interno trabeculectomy and iStent® inject were both effective in lowering IOP with a favourable and comparable safety profile in an intraindividual comparative study over a 12-months follow-up in OAG. However, longer follow-up of these patients will be necessary to determine long-term outcomes and to evaluate significant differences.

Evolving Surgical Interventions in the Treatment of Glaucoma

Interventions in the treatment of mild to moderate glaucoma have evolved to include a group of procedures collectively named "Minimally Invasive Glaucoma Surgery (MIGS)." These procedures are less invasive than traditional filtering surgery and setons and offer the benefit of an improved side-effect profile. A review of current published literature has shown that these procedures offer lower intraocular pressure, decrease reliance on topical medications, have no negative effect on refractive outcomes, and can be safely done following failed tube surgery.

Manchester iStent study: 3-year results and cost analysis

PurposeTo evaluate the safety, efficacy, and the cost of combined phacoemulsification and single iStent insertion in open angle glaucoma (OAG) at 3-years follow-up.MethodsThis was a prospective, uncontrolled, interventional case series. All subjects underwent single iStent implantation combined with cataract surgery by a single surgeon and were followed up over 3 years. Primary outcome measures were the reduction in intraocular pressure (IOP) and number of glaucoma drops at 1, 2, and 3 years. The costs of the procedure vs the cost of continuation of glaucoma drops were calculated and compared in patients who completed 3-years follow-up.ResultsForty-one patients were included in the study and thirty-six patients completed 3-years follow-up. Mean pre-op IOP was 21.2 mm Hg on 2.1 medications. Mean IOP was reduced to 15.9 mm Hg on 0.5 drops, 16.1 mm Hg on 1.0 drops, and 17.1 mm Hg (P<0.001) on 1.3 drops (P<0.001) at 1, 2, and 3 years, respectively. The overall cost of combined cataract surgery and iStent was estimated to be £829.32 more in total than conservative management with brand name eye drops over 3 years (£7.70 per patient per year) and £14 176.9 more if generic drops were used. (£131.3 per patient per year).ConclusionsCombined phaco-iStent proved to be a safe and effective way of managing patients with OAG over our 3-year follow-up period. The cost-effectiveness of the procedure may vary depending on whether brand name or generic eye drops are used.

iStent inject in phakic open angle glaucoma

BACKGROUND

The effectiveness and complication profile of the iStent inject implantation among different open angle glaucoma subgroups were analyzed.

METHODS

In this retrospective cohort outcome study, 35 consecutive patients suffering from glaucoma (primary open angle glaucoma (POAG) N = 17, pseudoexfoliation glaucoma (PEX) N = 15, and pigmentary glaucoma (PG) N = 3) were treated with the iStent inject. The intraocular pressure (IOP) and the number of antiglaucoma medications before and after surgery were evaluated.

RESULTS

In POAG, the mean IOP at 6 months measured 14.19 ± 1.38 mmHg with an average decrease of 33 % from preoperative IOP (p < 0.001), and 15.33 ± 1.07 mmHg with an average decrease of 35 % in PEX (p < 0.001), respectively. The number of antiglaucoma medications significantly decreased from 2.19 ± 0.91 to 0.88 ± 0.62 in POAG (p < 0.001) and from 2.33 ± 1.23 to 1.04 ± 0.30 in PEX (p < 0.001) after 6 months. In PG, IOP before surgery was 28.31 ± 3.21 mmHg and the number of antiglaucoma medications was 3.66 ± 0.57. One day after surgery, IOP decreased significantly to 12.33 mmHg ± 4.93 (p < 0.001). Within four weeks after surgery, IOP was raised above 30 mmHg in every patient. To exclude a steroid response, topical steroids were stopped, but IOP did not decrease. To exclude blockage, Nd:YAG - laser treatment of the visible opening of the iStents was performed. Since the IOP stayed high and escalation of antiglaucoma medication was insufficient to control IOP, trabeculectomy was performed.

CONCLUSIONS

In conclusion, implantation of the iStent inject has the ability to lower the postoperative IOP significantly in POAG and PEX after a short follow-up of 6 months with a favorable risk profile. However, limitation of this surgical procedure in phakic PG may exist and need to be investigated in further studies.

A review of the iStent(®) trabecular micro-bypass stent: safety and efficacy

There is a significant demand for procedures that can effectively treat glaucoma with low risk and good visual outcomes. To fill this void, procedures termed “minimally invasive glaucoma surgery”, are gaining in popularity. This review will focus on the safety and efficacy of one such minimally invasive glaucoma surgery procedure, the trabecular micro-bypass stent. This stent is intended to lower intraocular pressure by directly cannulating Schlemm’s canal and thereby enhancing aqueous outflow. Recent randomized controlled trials and case series have demonstrated the micro-bypass stent to be a relatively safe procedure, with limited complications and no serious adverse sequelae. The most common complication across all studies was stent obstruction or malposition, which generally did not result in any adverse outcome in vision or pressure control. In addition, increased rates of hypotony, choroidal hemorrhage, or infection were not seen with the micro-bypass stent in comparison to cataract surgery alone.