One-year surgical outcomes of the PreserFlo MicroShunt in glaucoma: a multicentre analysis

One-Year Outcomes of Preserflo Microshunt for Primary Open Angle Glaucoma: A Systematic Review and Meta-Analysis

PRCIS

This systematic review and meta-analysis concludes that the PreserFlo Microshunt glaucoma drainage device significantly reduces intraocular pressure in primary open angle glaucoma patients at 12 months postinsertion.

PURPOSE

A systematic review and meta-analysis on the effect of the PRESERFLO MicroShunt (PF-MS) on intraocular pressure (IOP) at 12 months has been conducted.

METHOD

The PubMed/MEDLINE, Embase, CENTRAL, Google Scholar, Scopus, and Web of Science databases were searched. Inclusion criteria required a diagnosis of open angle glaucoma, PF-MS insertion, and examination of IOP over time. Meta-analyses were conducted on the primary outcome of IOP and the secondary outcome of glaucoma medication regime. Adverse events were also noted.

RESULTS

Fourteen studies were identified for inclusion in the meta-analyses, of which none had a high risk of bias. The meta-analyses found a significant mean reduction in IOP of 9.07 mm Hg (95% CI: 7.88-10.25; P <0.0001) and a significant mean reduction in mean glaucoma medication requirement of 2.37 medications (95% CI: 2.15-2.60; P <0.0001). Hypotony and hyphaema are common early complications.

CONCLUSIONS

The PF-MS device significantly reduced both IOP and glaucoma medication requirement at 12 months postinsertion in individuals with open angle glaucoma without a significant adverse event burden. Further research is required to determine the economic and environmental effects of widely implementing the PF-MS device into clinical practice.

Long-term Outcomes of PreserFlo MicroShunt versus XEN45 Gel Stent in Open-Angle Glaucoma

PURPOSE

To compare two glaucoma drainage devices with subconjunctival filtration (MicroShunt and XEN) for open-angle glaucoma (OAG), with respect to effectiveness and safety.

PATIENTS AND METHODS

This is a single center, retrospective, interventional study. In total, 106 eyes of 95 patients with OAG underwent surgery. Of these patients, 51 eyes of 45 patients received a MicroShunt implantation and 55 eyes of 50 patients received an XEN implantation. Failure was defined as an intraocular pressure (IOP) lower than 5 or higher than 17 mmHg at the end of follow-up after 2 years, the need for surgical revision, secondary glaucoma surgery, or loss of light perception. Outcome was rated as complete success or qualified success, depending on whether it was achieved with or without anti-glaucomatous medications. Postoperative complications and interventions were also documented for both groups.

RESULTS

In the MicroShunt group, mean IOP decreased from 20.6 ± 7.5 mmHg at baseline to 13.0 ± 3.9 mmHg (p < 0.0001) after 2 years. In the XEN group, mean IOP was lowered from 22.5 ± 7.9 mmHg to 13.5 ± 4.2 mmHg (p < 0.0001). In both groups, the mean number of medications was significantly reduced (MicroShunt 2.7 ± 1.2 to 0.9 ± 2.5; p < 0.0001 vs. XEN 3.2 ± 0.9 to 1.1 ± 1.5; p < 0.0001). In regard to success rates, 37% of MicroShunt patients achieved complete success and 57% qualified success at the end of follow-up. In the XEN group, rates were 25 and 45%, respectively. Patient demographics differed between the two groups with respect to age (MicroShunt 72.8 ± 8.7 vs. XEN 67.7 ± 9.0 years; p = 0.002). Postoperative complications were comparable between the two groups.

CONCLUSION

Both MicroShunt and XEN are effective in significantly reducing IOP and glaucoma medications in OAG, and with a good safety profile.

[Glaucoma Filtration Surgery - Bleb-forming Procedures]

Glaucoma filtration surgery has been a standard surgical therapy for decades. An increasing knowledge about wound healing processes in the eye, the introduction of antimetabolite treatment and continuous improvements of the surgical technique helped making trabeculectomy - the prototype filtration surgery - a very effective therapeutic tool. However, best results will only be regularly achieved with a high level of experience and time dedicated to postoperative follow-up. Furthermore, the potential for severe early and late complications still remains high. Thus, novel stent-based filtration surgery approaches, such as the Preserflo and the XEN shunt have been introduced. This review presents these three bleb-forming filtration procedures, covering the basic principles of surgical technique, data on effectivity as well as complications.

Ab Interno Intraluminal Stent Insertion for Prolonged Hypotony After PreserFlo MicroShunt Implantation

This study aimed to present an effective and minimally invasive method for treating prolonged hypotony after PreserFlo MicroShunt (PMS) implantation, which can cause serious complications. A 79-year-old man with primary open-angle glaucoma of the right eye underwent ab interno intraluminal stent insertion for prolonged hypotony after PMS implantation. After making two corneal incisions at the 5 and 8 o'clock positions in the right eye, a viscoelastic material was injected into the anterior chamber. A 10-0 nylon suture was inserted into the anterior chamber through a corneal incision in the 5 o'clock position. Next, the 10-0 nylon suture was grasped and inserted into the PMS lumen as a stent with forceps, following which it was cut approximately 1 mm from the tip of the PMS using micro-iris scissors. Finally, the viscoelastic material in the anterior chamber was washed with a balanced salt solution, and self-closure of the two corneal incisions was confirmed. After ab interno intraluminal stent insertion, hypotony improved and stabilized at approximately 10 mmHg. The shallow anterior chamber, choroidal detachment, and hypotonic maculopathy improved rapidly. This novel technique demonstrated effectiveness and minimal invasiveness in treating prolonged hypotony after PMS implantation.

PRESERFLO™ Microshunt: 1-Year Results of a 25-Gauge vs. 27-Gauge Needle Tract

Background: The purpose of this study was to evaluate the effectiveness and safety of the PreserFlo™ microshunt (PMS) using a 25-Gauge vs. 27-Gauge needle tract. Methods: This is a prospective postoperative examination of 60 glaucoma eyes that received a PMS. The main outcome measures were intraocular pressure (IOP), glaucoma drug score (GDS), Kaplan-Meier success rates, complications, and secondary intervention rates. Two subgroups were formed for data comparison: 27-Gauge (27G), and 25-Gauge (25G). Success was defined as IOP < 18 mmHg together with ≥20% IOP reduction with medication allowed (qualified success = QS18) or not (full success = FS18). Results: IOP and GDS were reduced from baseline to the 1-year study visit as follows: All eyes from 23.4 ± 8.6 mmHg (3.1 ± 0.9) to 15.1 ± 5.9 mmHg (0.8 ± 1.1); 25G from 24.2 ± 7.3 mmHg (3.0 ± 0.8) to 12.7 ± 2.7 mmHg (0.5 ± 0.8); and 27G from 23.1 ± 9.2 mmHg (3.1 ± 1.0) to 16.2 ± 6.7 mmHg (0.9 ± 1.2). IOP at one year was lower in the 25G group compared to the 27G group (p = 0.035). Bleb needling was required in eight (13.3%) eyes and open bleb revisions in three (5.0%). Transient hypotony occurred in 21% and choroidal effusion in 8% of all eyes. Choroidal effusions were more frequent in the 25G group (21%) compared to the 27G group (2%, p = 0.031). One-year success rates were significantly higher in the 25G group compared to the 27G group for both QS18 (25G: 67.9% vs. 27G: 35.7%, p = 0.002) and FS18 (25G: 63.6% vs. 27G: 29.2%, p = 0.007). Conclusions: The PreserFlo microshunt is an effective and safe glaucoma surgery with a low rate of bleb revisions or needlings. We show that the 25G needle tract might be more efficient for IOP control at the cost of increased IOP-related complications compared to 27G.

Risk Factors for Failure in Glaucoma Patients Undergoing Microshunt Implantation

PURPOSE

To evaluate risk factors for failure of Microshunt in glaucoma patients.

DESIGN

Multicenter retrospective cohort study.

METHODS

The study included 220 eyes from 220 consecutive glaucoma patients undergoing Microshunt implantation at six glaucoma units. Four intraocular pressure (IOP) success criteria were defined: (A) IOP ≤21 mm Hg with ≥20% IOP reduction; (B) IOP ≤18 mm Hg with ≥20% IOP reduction; (C) IOP ≤15 mm Hg with ≥25% IOP reduction; and (D) IOP ≤12 mm Hg with ≥30% IOP reduction from baseline. Kaplan-Meier analysis was used to estimate success rates according to the criteria above, and multivariable Cox models were used to identified risk factors for failure according to criterion A.

RESULTS

Success rates varied based on different criteria, ranging from 43.3% to 62.5% (overall success for criteria D and A, respectively) and from 35.3% to 44.4% (complete success for criteria D and A, respectively) at 1-year follow-up. Higher intraoperative MMC concentration was associated with reduced risk of failure to maintain complete (0.4 vs 0.2 mg/mL: hazard ratio [HR] = 0.441, P < .001) and overall (0.4 vs 0.2 mg/mL: HR = 0.360, P = .004) success. For complete success, other risk factors for failure were pseudoexfoliation glaucoma/pigmentary glaucoma (HR = 1.641, P = .004), primary angle closure glaucoma (HR = 1.611, P < .001), and previous non-glaucomatous ocular surgeries (HR = 2.301, P = .002). For overall success, other risk factors for failure were lower preoperative IOP (for 1-mm Hg increase, HR = 0.934, P = .005), higher number of preoperative antiglaucoma agents (HR = 1.626, P < .001), and Microshunt combined with cataract surgery (HR = 1.526, P = .033).

CONCLUSIONS

This study identified risk factors for Microshunt failure, highlighting the importance of high intraoperative MMC dose and careful patient selection to optimize surgical success.

PRESERFLO MicroShunt implantation versus trabeculectomy for primary open-angle glaucoma: a two-year follow-up study

BACKGROUND

To compare the intermediate-term efficacy of PRESERFLO (PF) MicroShunt implantation with trabeculectomy (TE) in patients with primary open-angle glaucoma, focusing on longitudinal changes of functional and structural parameters.

METHODS

This retrospective comparative study included 104 eyes of 104 patients who underwent TE and 83 eyes of 83 patients that underwent PF implantation between January 2019 and December 2020, with a minimum follow-up of two years. Baseline and postoperative intraocular pressure (IOP), number of IOP-lowering medications, visual field mean defect (MD) and peripapillary retinal nerve fibre layer (RNFL) thickness measured using optical coherence tomography were assessed and compared between groups.

RESULTS

Baseline characteristics (age, sex, IOP, number of IOP-lowering medications, MD, RNFL thickness) were comparable between the two groups (all P > 0.05). During the two-year of follow-up, mean IOP decreased from 24.09 ± 1.15 mmHg and 21.67 ± 0.77 mmHg to 11.37 ± 1.13 mmHg (P < 0.001) and 15.50 ± 1.54 mmHg (P = 0.028), and the mean number of IOP-lowering medications decreased from 3.25 ± 0.14 and 3.51 ± 0.14 to 0.53 ± 0.14 (P < 0.001) and 1.06 ± 0.43 (P < 0.001) in the TE and PF groups, respectively. MD remained stable [- 11.54 ± 0.93 dB and - 11.17 ± 1.66 to - 10.67 ± 0.91 dB (P = 0.226) and - 10.40 ± 4.75 dB (P = 0.628) in the TE and PF groups, respectively] but RNFL thickness decreased continuously during follow-up [62.79 ± 1.94 µm and 62.62 ± 2.05 µm to 57.41 ± 1.81 µm (P < 0.001) and 60.22 ± 1.98 µm (P = 0.182) in the TE and PF groups, respectively].

CONCLUSION

PF implantation is comparably effective in the intermediate term in lowering IOP and reducing the use of IOP-lowering medications over a two-year follow-up period. Although visual field defects were stable, RNFL continued to decrease during postoperative follow-up.

PreserFlo Microshunt for the management of intraocular pressure elevation in iridocorneal endothelial syndrome

Purpose

To report on a case of angle-closure glaucoma secondary to iridocorneal endothelial (ICE) syndrome effectively managed with the PreserFlo Microshunt.

Observations

We report successful implantation of a PreserFlo Microshunt in a 57-year-old patient with secondary angle-closure glaucoma in the context of ICE syndrome. Following failure of medical therapy to adequately control intraocular pressure (IOP), the patient was consented for surgical intervention and underwent combined cataract surgery and PreserFlo Microshunt implantation. IOP at the last post-operative follow-up (5 months) was 12 mmHg with the patient on brinzolamide/timolol maleate (Azarga®). We report no complications in the post-operative period.

Conclusions and importance

The PreserFlo Microshunt may be a promising option for patients with ICE syndrome who fail medical therapy. Implantation of this device was well tolerated in the presented case.

Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges

The development of minimally invasive glaucoma surgeries (MIGSs) was intended to provide safe and modestly efficacious modalities for early intervention of mild-to-moderate glaucoma, with minimal trauma and rapid recovery. They were mainly ab interno procedures that reduce intraocular pressure by facilitating the aqueous outflow by bypassing the trabecular meshwork resistance, reinforcing the uveoscleral flow via the supraciliary space, and reducing aqueous production by the ciliary body. While the cumulating evidence helps shape the role of the available MIGS, the exponential new development and advancement in this field has expanded the territory of MIGS. Apart from developing subconjunctival MIGS filtration devices (Xen gel stent and PRESERFLO MicroShunt), there is a tendency to revisit the "traditional" MIGS for alternative use and to modify the procedures with consideration of the fundamental aqueous outflow physiology. Combined MIGS has also been suggested, based on the theory that their different mechanisms may provide additive or synergistic effects. The advancement of laser procedures is also promising and could supplement unmet needs along the glaucoma treatment algorithm. This review examines the broad array of MIGS, updates the recent findings, discusses their potential alternative applications, and explores future challenges.

Dislocation of the PreserFlo MicroShunt During a Postsurgical Needling Procedure

We report a case of PreserFlo MicroShunt (PFM) dislocation following a postsurgical needling procedure. A 58-year-old woman underwent PFM implantation for exfoliation glaucoma in her left eye (OS). There were no intraoperative complications. Preoperatively, her best-corrected visual acuity (BCVA) was 0.6, and her intraocular pressure (IOP) was 25 mmHg with three antiglaucoma medications in the OS. On postoperative day 21, the IOP was 21 mmHg OS, and the filtration bleb had shrunk. A needling procedure was performed using a sharp 26-gauge needle to lower the IOP. On postoperative day 29, the BCVA was 0.02, and the IOP was 60 mmHg OS. Gonioscopy revealed no device tip in the anterior chamber, and peripheral anterior synechia was observed at the site of PFM insertion. Anterior segment optical coherence tomography showed a dislocated device in the subconjunctival space. On postoperative day 35, the dislocated PFM was removed, and a new device was inserted. Following the reoperation, no further complications were observed, and bleb formation was obtained. In conclusion, like other glaucoma filtering surgeries, PFM may require postsurgical needling procedures. Needling procedures may cause PFM dislocation and IOP rise, resulting in the requirement for further IOP-reducing procedures.

The Development of a SIBS Shunt to Treat Glaucoma

Many pharmaceutical and medical device start-up companies share similar goals. Each experience is different and offers important lessons for companies seeking Food and Drug Administration approval. This article offers important advice for budding entrepreneurs as it discusses some career-altering decisions, lessons learned in the start-up world, the technology leading up to innovation, the relevant science, medicine, chemistry, and engineering, the need to develop novel biomaterials, the regulatory path, and the business process culminating in the development of a Poly(styrene-block-isobutylene-block-Styrene)-based microshunt to treat glaucoma that led to the founding of InnFocus, Inc. (Miami, FL) in 2004, and then the acquisition of InnFocus by Santen Pharmaceuticals (Osaka, Japan) in 2016.

PRESERFLO ™ MicroShunt versus trabeculectomy: 1-year results on efficacy and safety

PURPOSE

To compare the efficacy and safety of the PRESERFLO™ MicroShunt versus trabeculectomy in patients with primary open-angle glaucoma (POAG) after one year.

PATIENTS AND METHODS

Institutional prospective interventional cohort study comparing eyes with POAG, which had received the PRESERFLO™ MicroShunt versus trabeculectomy. The MicroShunt group was matched with the trabeculectomy group for age, known duration of disease, and number and classes of intraocular pressure (IOP) lowering medications to have similar conjunctival conditions. The study is part of the Dresden Glaucoma and Treatment Study, using a uniform study design, with the same inclusion and exclusion criteria, follow-ups and standardized definitions of success and failure for both procedures.

PRIMARY OUTCOME MEASURES

mean diurnal IOP (mdIOP, mean of 6 measurements), peak IOP, and IOP fluctuations.

SECONDARY OUTCOME MEASURES

success rates, number of IOP lowering medications, visual acuity, visual fields, complications, surgical interventions, and adverse events.

RESULTS

Sixty eyes of 60 patients, 30 in each group, were analyzed after 1-year follow-ups. Median [Q25, Q75] mdIOP (mmHg) dropped from 16.2 [13.8-21.5] to 10.5 [8.9-13.5] in the MicroShunt and from 17.6 [15.6-24.0] to 11.1 [9.5-12.3] in the trabeculectomy group, both without glaucoma medications. Reduction of mdIOP (P = .596), peak IOP (P = .702), and IOP fluctuations (P = .528) was not statistically significantly different between groups. The rate of interventions was statistically significantly higher in the trabeculectomy group, especially in the early postoperative period (P = .018). None of the patients experienced severe adverse events.

CONCLUSION

Both procedures are equally effective and safe in lowering mdIOP, peak IOP and IOP fluctuations in patients with POAG, one year after surgery.

CLINICAL TRIAL REGISTRATION

NCT02959242.

[Comparison of new and old procedures in glaucoma surgery : Trabeculectomy, Preserflo and XEN]

Glaucoma is one of the most frequent causes of irreversible blindness worldwide. The main risk factor of the disease is an individually too high intraocular pressure and pressure reduction is still the only established treatment. If conservative pressure reduction and adherence are insufficient, and if the patient is unable to tolerate conservative treatment, surgical procedures become necessary. There are nowadays more than a dozen different surgical procedures for lowering the pressure. This article presents and discusses the procedures that have a subconjunctival pre-equatorial drainage in common. These include trabeculectomy, the XEN-gel implant and the Preserflo microshunt.

Systematic Preserflo MicroShunt Intraluminal Stenting for Hypotony Prevention in Highly Myopic Patients: A Comparative Study

Transient hypotony is the most common early complication after Preserflo MicroShunt (PMS) implantation. High myopia is a risk factor for the development of postoperative hypotony-related complications; therefore, it is advisable that PMS implantation in patients should be performed while employing hypotony preventive measures. The aim of this study is to compare the frequency of postoperative hypotony and hypotony-related complications in high-risk myopic patients after PMS implantation with and without intraluminal 10.0 nylon suture stenting. This is a retrospective, case-control, comparative study of 42 eyes with primary open-angle glaucoma (POAG) and severe myopia that underwent PMS implantation. A total of 21 eyes underwent a non-stented PMS implantation (nsPMS), while in the remaining eyes (21 eyes), PMS was implanted with an intraluminal suture (isPMS group). Hypotony occurred in six (28.57%) eyes in the nsPMS group and none in the isPMS group. Choroidal detachment occurred in three eyes in the nsPMS group; two of them were associated with the shallow anterior chamber and one was associated with macular folds. At 6 months after surgery, the mean IOP was 12.1 ± 3.16 mmHg and 13.43 ± 5.22 mmHg (p = 0.41) in the nsPMS and isPMS group, respectively. PMS intraluminal stenting is an effective measure to prevent early postoperative hypotony in POAG highly myopic patients.

[Revision of the PRESERFLO® MicroShunt with ologen and mitomycin C]

Bleb failure after implantation of filtering stents (e.g. Preserflo Stent) is a frequent challenge in glaucoma surgery that has occurred in recent years. In the following, a technique for open bleb revision with mitomycin C (0.2 mg/ml) and ologen implantation is presented, which is intended to re-establish the filtration volume lost due to fibrosis and a long-term preservation.

Effectiveness and cost-effectiveness of MicroShunt implantation versus standard trabeculectomy for open-angle glaucoma (a SIGHT study): study protocol of a multicentre randomised controlled trial

BACKGROUND

Trabeculectomy is the "gold standard" initial surgical procedure for open-angle glaucoma worldwide. During the last decade, the introduction of less invasive procedures, including new bleb-forming surgery such as the MicroShunt, has altered the approach of glaucoma management. At present, there is insufficient evidence comparing the effectiveness between these procedures nor versus trabeculectomy. Furthermore, there is no data available on patient impact and cost-effectiveness. This study aims to address this gap in evidence and establish whether MicroShunt implantation is non-inferior compared to trabeculectomy with regard to effectiveness and whether it is cost-effective.

METHODS

A multicentre, non-inferiority, randomised controlled trial (RCT) studying open-angle glaucoma with an indication for surgery will be conducted. Patients with previous ocular surgery except for phacoemulsification are excluded, as are patients with ocular comorbidity compromising the visual field or requiring a combined procedure. After informed consent is obtained, patients will be randomly allocated to the intervention, a PRESERFLO™ MicroShunt implantation, or the control group, trabeculectomy, using block randomisation (blocks of 2, 4 or 6 patients). In total, 124 patients will be randomised in a 1:1 ratio, stratified by centre. The primary endpoint will be intraocular pressure (IOP) one year after surgery. Secondary outcomes include IOP-lowering medication use, treatment failure, visual acuity, visual field progression, additional interventions, adverse events, patient-reported outcome measures (PROMs), and cost-effectiveness. Study outcomes will be measured up to 12 months postoperatively.

DISCUSSION

This study protocol describes the design of a multicentre non-inferiority randomised controlled trial. To this date, cost-effectiveness studies evaluating the MicroShunt have not been undertaken. This multicentre RCT will provide more insight into whether MicroShunt implantation is non-inferior compared to standard trabeculectomy regarding postoperative IOP and whether MicroShunt implantation is cost-effective.

TRIAL REGISTRATION

ClinicalTrials.gov, Identifier: NCT03931564 , Registered 30 April 2019.

Efficacy of the PRESERFLO MicroShunt and a Meta-Analysis of the Literature

Background: Recent studies on the PRESERFLO MicroShunt suggest that it may be effective in lowering intraocular pressure (IOP); however, the number of studies on this device remains limited. Therefore, we assessed the efficacy of the PRESERFLO MicroShunt in patients with glaucoma and performed a meta-analysis of published results. Methods: Prospective study including all patients that underwent PRESERFLO MicroShunt surgery from 2018 onwards. Sub-analyses were performed for cataract-combined procedures. To compare our results, we performed a systematic review and meta-analysis. IOP, IOP-lowering medication and surgical complications reported in the retrieved studies were assessed. Results: A total of 72 eyes underwent PRESERFLO-implant surgery (59 as standalone procedure and 13 as cataract-combined procedure). No significant differences were found in IOP and IOP-lowering medication between both groups. The mean ± standard deviation IOP and IOP-lowering medications of both groups taken together declined from 21.72 ± 8.35 to 15.92 ± 8.54 mmHg (p < 0.001, 26.7% reduction) and 3.40 to 0.93 (p < 0.001, 72.6% reduction) at 1 year follow-up, respectively. Secondary surgeries were required in 19.4% of eyes, the majority (71.4%) within 6 months. The meta-analysis including 14 studies (totaling 1213 PRESERFLO MicroShunt surgeries) from the systematic review showed a mean preoperative IOP and IOP-lowering medication of 22.28 ± 5.38 and 2.97 ± 1.07, respectively. The three-years postoperative pooled mean was (weighted mean difference, 95% CI) 11.07 (10.27 [8.23−12.32], p < 0.001) mmHg and 0.91 (1.77 [1.26−2.28], p < 0.001) for IOP and IOP-lowering medication, respectively. The most common reported complication was hypotony (2−39%). Conclusion: The PRESERFLO MicroShunt is effective and safe in lowering IOP and the number of IOP-lowering medications.

Minimally Invasive Glaucoma Surgery: Safety of Individual Devices

Primary open-angle glaucoma progression in those already on maximal medical therapy has traditionally been treated with trabeculectomy, a surgical procedure that carries a high degree of morbidity. In the last few decades, significant advances have been made in the field of minimally invasive glaucoma surgery (MIGS) devices, which aim to defer or prevent trabeculectomy via less arduous surgical techniques in certain types of glaucoma. Although reviews have been published examining the efficacy of various MIGS techniques, no article synthesises the comparative safety of all available devices. We performed a literature review examining the safety of MIGS devices. Fifteen devices were included, variously attempting to increase aqueous outflow through the trabecular meshwork or the suprachoroidal space, shunting into the subconjunctival space, or reducing aqueous production through ciliary body ablation. Notably, the earliest product attempting to increase outflow to the suprachoroidal space, Alcon's CyPass Micro-Stent, was withdrawn from the market due to concerns regarding increased corneal endothelial cell loss at five years post-implantation. All other devices were described as well-tolerated, with the most common adverse effects including hyphaema, intraocular pressure spikes, and device migration or obstruction. MIGS devices are purported to be uniformly safe, and many studies report no statistically significant increased complications beyond those associated with cataract surgery alone. It is important to note, however, the generally poor quality of current studies, with a dearth of randomised, or even prospective, data, and a large proportion of studies funded by device producers.

MicroShunt versus Trabeculectomy for Surgical Management of Glaucoma: A Retrospective Analysis

This case-control study aims to compare the efficacy, safety, and postoperative burden of MicroShunt versus trabeculectomy. The first consecutive cohort of MicroShunt procedures (n = 101) was matched to recent historical trabeculectomy procedures (n = 101) at two London hospital trusts. Primary endpoints included changes in intraocular pressure (IOP) and glaucoma medications. Secondary outcome measures included changes in retinal nerve fibre layer (RNFL) thickness, rates of complications, further theatre interventions, and the number of postoperative visits. From the baseline to Month-18, the median [interquartile range] IOP decreased from 22 [17–29] mmHg (on 4 [3–4] medications) to 15 [10–17] mmHg (on 0 [0–2] medications) and from 20 [16–28] mmHg (on 4 [3–4] medications) to 11 [10–13] mmHg (on 0 [0–0] medications) in the MicroShunt and trabeculectomy groups, respectively. IOP from Month-3 was significantly higher in the MicroShunt group (p = 0.006), with an increased number of medications from Month-12 (p = 0.024). There were greater RNFL thicknesses from Month-6 in the MicroShunt group (p = 0.005). The rates of complications were similar (p = 0.060) but with fewer interventions (p = 0.031) and postoperative visits (p = 0.001) in the MicroShunt group. Therefore, MicroShunt has inferior efficacy to trabeculectomy in lowering IOP and medications but provides a better safety profile and postoperative burden and may delay RNFL loss.