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

Long-term outcomes of canaloplasty and phaco-canaloplasty in the treatment of open angle glaucoma: a single-surgeon experience

PURPOSE

To evaluate and compare the long-term outcomes of canaloplasty and phaco-canaloplasty in the treatment of open angle glaucoma and assess the prognostic factors associated with surgical outcome.

METHODS

A 48-month retrospective analysis was performed on n = 133 open angle glaucoma eyes treated with canaloplasty and n = 57 open angle glaucoma eyes treated with phaco-canaloplasty by a single surgeon. Surgical success was defined according to six criteria, achieving a target intraocular pressure (IOP) ≤ 21, 18 or 15 mmHg on glaucoma medications (qualified success) or without any further treatment (complete success), including laser therapy or surgery. Kaplan-Meier survival analysis and Cox regression analysis were performed to evaluate surgical success and preoperative factors associated with surgical outcome. Surgical complications in the early postoperative period were compared between canaloplasty and phaco-canaloplasty.

RESULTS

Canaloplasty and phaco-canaloplasty significantly reduced postoperative IOP and number of glaucoma medications (p = 0.001 for both). Phaco-canaloplasty showed higher rates of cumulative surgical success over canaloplasty, but only for target IOP ≤ 21 and ≤ 18 (p = 0.018 and p = 0.011, respectively). A preoperative number of > 4 glaucoma medications predicted surgical failure. Phaco-canaloplasty was associated with a higher rate of IOP peaks in the first month compared with canaloplasty (40.4% vs 12.7%, p = 0.000).

CONCLUSION

Canaloplasty and phaco-canaloplasty demonstrated long-term efficacy in the treatment of open angle glaucoma, with phaco-canaloplasty showing higher rates of surgical success compared to canaloplasty, but not for target IOPs lower than 16 mmHg. Patients on more than 4 preoperative glaucoma medications may not be good candidates for canaloplasty and may benefit from other surgical options.

Effectiveness of Angle-Based Minimally Invasive Glaucoma Surgery after Laser Trabeculoplasty: An Analysis of the IRIS® Registry (Intelligent Research in Sight)

OBJECTIVE

Angle-based minimally invasive glaucoma surgery (ab-MIGS) has grown substantially, although long-term efficacy is poorly understood. We analyze ab-MIGS effectiveness with and without preceding laser trabeculoplasty (LTP).

DESIGN

Retrospective cohort study.

SUBJECTS

Eyes undergoing ab-MIGS (Canaloplasty, Goniotomy, Trabectome, and iStent) with and without prior laser trabeculoplasty (< 2 years preceding MIGS) were identified in the IRIS® Registry (Intelligent Research in Sight) 2013 to 2018.

METHODS

Propensity score matching (PSM) was undertaken to define the following 4 cohorts: (1) standalone ab-MIGS, no prior LTP vs. (2) standalone ab-MIGS, with prior LTP; and (3) ab-MIGS + phacoemulsification, no prior LTP vs. (4) ab-MIGS + phacoemulsification, with prior LTP.

MAIN OUTCOME MEASURES

Failure was defined as subsequent glaucoma reoperation after ab-MIGS (either MIGS or traditional glaucoma surgery). Time-to-event outcome and incidence rates were calculated using survival analysis, and adjusted hazard ratios (aHRs) were generated using multivariate Cox proportional hazards models. Medication data were not available for analysis.

RESULTS

A total of 164 965 unique MIGS procedures were performed, from 2013 to 2018. After PSM, we identified 954 eyes undergoing standalone ab-MIGS and 7522 undergoing ab-MIGS + phacoemulsification. For eyes undergoing standalone ab-MIGS, those with prior LTP (n = 477) were more likely to undergo reoperation vs. those without LTP (n = 477) at 6 and 12 months. In multivariable models, those with prior LTP were more likely to undergo reoperation over the 36-month period vs. those without prior LTP (aHR, 1.53; CI, 1.15-2.04; P = 0.004). For eyes undergoing ab-MIGS + phacoemulsification, those with prior LTP (n = 3761) were more likely to undergo reoperation vs. those without LTP (n = 3761) at 12, 24, and 36 months. In multivariable models, those with prior LTP were more likely to undergo reoperation over the 36-month period vs. those without prior LTP (aHR, 1.53 CI, 1.15-2.04; P = 0.004).

CONCLUSIONS

Prior LTP may be associated with a higher chance of subsequent glaucoma surgery following ab-MIGS, either with or without concurrent phacoemulsification. These findings have important implications for understanding who may benefit most from ab-MIGS, and for guiding patient and surgeon treatment expectations.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Ab interno canaloplasty versus gonioscopy-assisted transluminal trabeculotomy in open-angle glaucoma: a randomised controlled trial

OBJECTIVE

To compare the efficacy and safety of ab interno canaloplasty (ABiC) with gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with open-angle glaucoma (OAG).

METHOD

This randomised clinical trial recruited eyes with OAG and no previous incisional ocular surgery, among which 38 were randomised to ABiC and 39 to GATT. Follow-ups were performed at 1, 3, 6 and 12 months postoperatively. The primary outcome measures were intraocular pressure (IOP) and use of glaucoma medication at 12 months postoperatively. The secondary outcome measure was complete surgical success (not requiring glaucoma surgery, IOP ≤21 mm Hg and non-use of glaucoma medications).

RESULTS

Both groups had similar demographic and ocular characteristics. A total of 71 of the 77 subjects (92.2%) completed 12-month follow-up. At 12 months, mean IOP was 19.0±5.2 mm Hg in the ABiC group and 16.0±3.1 mm Hg in the GATT group (p=0.003). Overall, 57.2% of ABiC patients and 77.8% of GATT patients were medication free (p=0.06). The number of glaucoma medications was 0.9±1.3 in the ABiC group and 0.6±1.2 in the GATT group (p=0.27). The 12-month cumulative rate of complete surgical success was 56% in the ABiC group and 75% in the GATT group (p=0.09). Three eyes in the ABiC group and one eye in the GATT group required additional glaucoma surgery. Hyphema (87% vs 47%) and supraciliary effusion (92% vs 71%) were noted more often in the GATT group than in the ABiC group.

CONCLUSIONS

The preliminary result showed that GATT had an advantage over ABiC in IOP reduction for OAG patients, accompanied by favourable safety at 12-month postoperatively.

TRIAL REGISTRATION NUMBER

ChiCTR1800016933.

A Review of Canaloplasty in the Treatment and Management of Glaucoma

Aim

To review the published literature evaluating the safety and efficacy outcomes of canaloplasty performed in the treatment of glaucoma.

Background

Canaloplasty is a nonpenetrating glaucoma procedure involving combined 360° circumnavigation and viscodilation of Schlemm's canal. The procedure may be performed under an ab externo (with tensioning suture) or ab-interno (conjunctiva-sparing) approach. Given the wide variety of glaucoma procedure types and approaches, further investigation into the role of canaloplasty in ophthalmological practice is warranted. The objectives of this narrative review are to synthesize the existing literature in order to investigate indications, safety and efficacy outcomes, and the optimal place of canaloplasty in glaucoma treatment and management.

Review of results

A total of 60 articles were included in this review. Both ab externo and ab-interno canaloplasty (ABiC) were found to be significantly effective at reducing intraocular pressure (IOP) and glaucoma medication burdens in patients with mild-to-moderate open-angle glaucoma (OAG). These findings remained consistent regardless of phacoemulsification status. ABiC was found to exhibit a safety profile favorable compared to trabeculectomy and comparable to minimally invasive trabecular bypass implants.

Conclusion

Canaloplasty is a nonpenetrating surgical intervention that is highly effective in treating patients with mild-to-moderate OAG across a large variety of clinical scenarios.

Clinical significance

These findings support the clinical use of canaloplasty in ophthalmological practice, clarify its patient profile, and compare procedural outcomes to other minimally invasive glaucoma surgery (MIGS) devices on the market.

How to cite this article

Wagner IV, Towne C, Saade MC, et al. A Review of Canaloplasty in the Treatment and Management of Glaucoma. J Curr Glaucoma Pract 2024;18(2):79-85.

Four-Year Efficacy and Safety of iTrack Ab-interno Canaloplasty as a Standalone Procedure and Combined with Cataract Surgery in Open-Angle Glaucoma

PURPOSE

To evaluate the long-term effectiveness of ab-interno canaloplasty (ABiC), performed with the iTrack microcatheter (Nova Eye Medical, Fremont, CA, USA), in reducing intraocular pressure (IOP) as well as the number of required glaucoma medications in patients with open-angle glaucoma (OAG).

METHODS

In this retrospective single-center consecutive case series, 27 eyes of 21 patients (mean age 77.3 ± 5.8 years) were treated with ABiC performed as a standalone procedure or combined with cataract surgery. Patients with uncontrolled IOP OAG or controlled IOP (≤ 18 mmHg) OAG with intolerance to medications or lack of compliance were included. Patients were followed for up to 4 years following the procedure. The iTrack microcatheter was used to perform a 360-degree circumferential intubation and viscodilation of Schlemm's canal. Primary efficacy endpoints included IOP and the number of glaucoma medications at 12, 24, 36, and 48 months after surgery.

RESULTS

In all eyes, mean IOP and number of glaucoma medications were significantly reduced from 19.8 ± 5.2 mmHg and 1.9 ± 1.00 at baseline to 14.6 ± 3 mmHg and 0.9 ± 0.8, respectively, at the 48-month follow-up (p < 0.001). IOP was stable from 12 months to 48 months (p > 0.005). After 48 months, 39% of the eyes required zero medications compared to 3.7% at baseline, and 72.2% of eyes required only one medication or less. Of all eyes, 77.8% recorded an IOP ≤ 17 mmHg. No serious complications were recorded.

CONCLUSION

iTrack ABiC performed as a standalone procedure or in combination with cataract surgery significantly reduced IOP and number of medications in patients with OAG up to 4 years after the procedure.

New Devices in Glaucoma

Glaucoma remains a leading cause of blindness globally. Minimally invasive treatment techniques are rapidly expanding the availability of therapeutic options for glaucoma. These include devices aimed at enhancing outflow through the subconjunctival space, Schlemm's canal, and suprachoroidal space, sustained-release drug delivery devices, and extraocular devices aiming to reduce glaucomatous progression through other novel means. In this review, we provide an overview of several novel devices either newly available or in development for the medical and surgical management of glaucoma. Further studies are required to determine the long-term efficacy of these devices and how they will integrate into the current landscape of glaucoma management.

Minimally Invasive Glaucoma Surgery: A Review of the Literature

Minimally invasive glaucoma surgery (MIGS) has emerged as a novel approach in the glaucoma treatment spectrum, offering a range of diverse procedures and devices aimed at reducing intraocular pressure (IOP). MIGS can be broadly classified into several categories: those that enhance trabecular outflow (Trabectome, iStent, Hydrus Microstent, Kahook Dual Blade, high frequency deep sclerotomy, and gonioscopy-assisted transluminal trabeculotomy), those that augment suprachoroidal outflow (CyPass Microstent and iStent Supra), those that target Schlemm's canal (TRAB360 and the OMNI Surgical System, Streamline, and Ab Interno Canaloplasty), and conjunctival bleb-forming procedures (EX-PRESS Glaucoma Filtration Device, Xen Gel Stent and PreserFlo MicroShunt). MIGS is considered to have a shorter surgical time and fewer severe complications when compared to traditional glaucoma surgeries such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves). This literature review comprehensively examines the distinct MIGS devices and procedures, their underlying mechanisms, and clinical outcomes, emphasizing the importance of evaluating the efficacy and complications of each approach individually. As the field of MIGS continues to evolve, it is crucial to prioritize high-quality, long-term studies to better understand the safety and effectiveness of these innovative interventions in glaucoma management.

Combined Phacoemulsification and STREAMLINE Surgical System Canal of Schlemm Transluminal Dilation in Eyes of Hispanic Patients with Mild to Moderate Glaucoma

Purpose

To characterize clinical outcomes of transluminal dilation of the canal of Schlemm using the STREAMLINE Surgical System combined with phacoemulsification in eyes of Hispanic patients diagnosed with mild to moderate primary open-angle glaucoma.

Methods

This was a prospective analysis of all cases performed and followed up to 12 months. All eyes underwent medication washout preoperatively. Reduction in intraocular pressure (IOP) from unmedicated baseline, as well as medications from pre-washout baseline, were analyzed at postoperative Day 1, Week 1, and Months 1, 3, 6, 9, and 12.

Results

All 37 patients were Hispanic, 83.8% were female, and mean (standard deviation) age was 66.0 (10.5) years. Mean medicated preoperative IOP was 16.9 (3.2) mmHg using a mean of 2.1 (0.9) medications, unmedicated baseline IOP (after washout) was 23.2 (2.3) mmHg, and mean IOP at every postoperative study visit was significantly lower (p<0.0002). Mean IOP from month 1 through the first postoperative year ranged from 14.7-16.2 mmHg, representing a reduction of 7.0-8.5 mmHg (30.7-36.5%). At month 12, 80% of all eyes (28/35) and 77.8% of medication-free eyes (14/18) had IOP reduction ≥20% from unmedicated baseline, and 51.4% of eyes (18/35) were medication-free. Mean medication use was significantly reduced (by 59.9-74.6%, p<0.0001) at every postoperative study visit. The only adverse event occurring in >1 eye was high IOP (n=4) which was responsive to topical medical therapy; no adverse events were attributed to the transluminal dilation procedure.

Conclusion

Transluminal dilation of the canal of Schlemm using the STREAMLINE Surgical System combined with phacoemulsification safely and effectively reduced both IOP and dependence on IOP-lowering medications in a Hispanic population diagnosed with POAG and should be considered at the time of phacoemulsification in Hispanic patients who have a need for IOP reduction, medication reduction, or both.

The case for standalone micro-invasive glaucoma surgery: rethinking the role of surgery in the glaucoma treatment paradigm

PURPOSE OF REVIEW

To highlight progress in glaucoma therapy challenging the traditional medication-first approach and present evidence supporting early standalone surgery in the era of micro-invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Medical therapy is limited by well documented poor adherence that compromises the quality of intraocular pressure reduction. Results from modern clinical trials demonstrate advantages of selective laser trabeculoplasty and MIGS procedures in terms of both IOP control and progression risk.

SUMMARY

The MIGS options for pseudophakic or precataractous patients are limited by regulatory rules that require the performance of some procedures only at the time of cataract surgery. These include the iStent/iStent Inject and the Hydrus implants. Nonbleb-forming procedures currently available for standalone use in eyes with mild-moderate primary open-angle glaucoma include gonioscopy-assisted transluminal trabeculotomy (which lowers IOP by 28-61% and medication use by 38-73% in various studies), trabecular ablation with the Trabectome (23-39% and 21-43%, respectively), excisional goniotomy with the Kahook Dual Blade (15-36% and 15-40%, respectively), ab interno canaloplasty (35% and 57%, respectively), and combined canaloplasty and trabeculotomy using the OMNI system (39-40% and 64-73%, respectively). For patients who would benefit from early standalone surgery, these procedures offer meaningful reductions in both IOP and medication burden.

The PreserFlo MicroShunt in the Context of Minimally Invasive Glaucoma Surgery: A Narrative Review

Recently, the quest for novel glaucoma surgical techniques and devices has been underway. Trabeculectomy remains the gold standard, but it requires the implantation of glaucoma drainage devices and frequent follow-ups, and it also carries a high risk of serious complications. The need for less invasive and safer procedures has led to the development of minimally invasive glaucoma surgery (MIGS), particularly for patients with mild-to-moderate disease. Among them, minimally invasive bleb surgery seems to be effective in classical glaucoma surgery, while maintaining MIGS benefits. The relatively new PreserFlo® MicroShunt (Santen, Osaka, Japan) is registered in Europe. It was released in 2019 for the treatment of patients with early-to-advanced open-angle glaucoma, where intraocular pressure (IOP) remains uncontrolled while on maximum tolerated medication and/or where glaucoma progression warrants surgery. This review focuses on the place of the PreserFlo MicroShunt, characterized by ab externo implantation, among MIGS procedures, discussing its advantages and disadvantages. The mechanisms of action, technical aspects, efficacy, and safety issues are summarized. The surgical technique, its efficacy, and safety profile are described, and directions for future studies are indicated. The PreserFlo MicroShunt ensures a high safety profile, minimal anatomical disruption, meaningful IOP-lowering effect, and ease of use for patients and physicians.

Long-Term Clinical and Safety Outcomes of Canaloplasty Performed across All Grades of Glaucoma Severity

Purpose

To investigate the clinical effectiveness of canaloplasty performed with an ab interno technique using the iTrack microcatheter (Nova Eye Medical) in patients with mild-moderate glaucoma as compared to severe glaucoma.

Methods

This is a retrospective single-center case series. Patients were preoperatively categorized as mild/moderate vs. severe glaucoma assessed using the mean deviation (MD) score and controlled group (baseline intraocular pressure (IOP) ≤18 mmHg) vs. uncontrolled group (>18 mmHg). All patients with glaucoma were eligible for recruitment except those who had undergone previous glaucoma surgery (with the exception of selective laser trabeculoplasty or SLT). Patients underwent canaloplasty via an ab interno surgical technique with or without phacoemulsification and were monitored for IOP, glaucoma medication usage, and surgical complications.

Results

In total, 72 eyes were followed for 3.4 ± 0.5 years. Mean pre-op IOP (mmHg) was 19.3 ± 7.7 in the standalone group (n = 9) and 18.5 ± 5.6 in the combined group (n = 63) (p=0.38). At the last follow-up, mean IOP reduced by 36% to 12.4 ± 4.4 (p=0.02) in the standalone group and by 26% to 13.7 ± 4.8 in the combined group (p < 0.001). Mean pre-op IOP (mmHg) was 18.6 ± 5.2 in the severe group (n = 24) and 18.6 ± 6.2 in the mild-moderate group (n = 48) (p=0.48). Mean IOP was 14.1 ± 6.3 (-24%; p < 0.001) and 13.3 ± 3.7 (-29%; p < 0.001), respectively, at the last follow-up. Mean glaucoma medication usage decreased from 2.5 ± 0.9 to 2.1 ± 0.9 (-15%; p=0.083) in the severe group and 2.3 ± 1.0 to 1.4 ± 1.3 (-40%; p < 0.001) in the mild/moderate group. There was one localized Descemet's membrane detachment in the moderate group.

Conclusion

iTrack canaloplasty achieved a statistically significant IOP reduction in mild-moderate and severe eyes and was found to be an effective option for reducing IOP and medications in patients with mild-moderate primary open-angle glaucoma (POAG). In severe eyes, it has reduced IOP while the medications remained stable.

Safety and Efficacy of Three Variants of Canaloplasty with Phacoemulsification to Treat Open-Angle Glaucoma and Cataract: 12-Month Follow-Up

Background: A single-center prospective randomized observational study to compare three types of canaloplasty, i.e., ab externo (ABeC), minicanaloplasty (miniABeC) and ab interno, (ABiC) combined with cataract surgery in primary open-angle glaucoma (POAG) patients over 12 months. Methods: 48 POAG patients underwent one of three canaloplasty procedures: ABeC (16 eyes), miniABeC (16 eyes) or ABiC (16 eyes) or combined with phacoemulsification. Patients were assessed at baseline, at day 0–1–7 and at month 1–3–6–12. Successful treatment was defined as unmedicated IOP reduction ≥20%. Complete surgical success was defined as an IOP ≤ 15 mmHg without medications, and a qualified surgical success as IOP ≤ 15 mmHg with or without medications. Results: Pre-washout IOP median values (mmHg) were 17 (ABeC), 18 (miniABeC) and 17 (AbiC) and decreased at 12-month follow up postoperatively to 13 (p = 0.005), 13 (p = 0.004) and 14 (p = 0.008), respectively—successful treatment was achieved in approximately 100% of patients for ABeC and in 93.8% for both miniABeC and AbiC groups. Preoperatively, the median number of medications was 2.0 (range 1–3) (ABeC), 2.0 (1–3) (miniABeC) and 2.0 (0–4) (ABiC); 12-month post-operatively, all medications were withdrawn except in two patients (followed miniABeC and AbiC). Conclusions: The three variants of canaloplasty significantly reduced IOP and the number of medications in patients with mild to moderate POAG and gave no significant complications.

Modified suture-assisted canaloplasty in Asians with primary open-angle glaucoma: a prospective study with 12-month follow-up

BACKGROUND

To evaluate the efficacy and safety of modified suture-assisted canaloplasty in Asians with primary open-angle glaucoma (POAG).

METHODS

A prospective, consecutive cases study, evaluating a modified canaloplasty by twisted 6/0 suture was performed on Asian POAG patients. Three modifications of this canaloplasty included opening the Schlemm's canal by viscocanalostomy, circumferential probing by a twisted 6/0 suture and loose suture of the superficial scleral flap. The twisted 6/0 suture was selected as a prober based on characteristical analysis of size and contact measurement as well as chemical composition conducted among 5/0, twisted 6/0 polypropylene sutures and the microcatheter. Success criteria were defined as intraocular pressure (IOP) ≤ 21 mmHg, 18 mmHg, 15 mmHg, and ≥ 20% reduction without (complete success) or with medications (qualified success). Efficacy was assessed by the success rate of circumferential catheterization, IOP values, the success rate of the surgery, the number of IOP-lowering medications, best-corrected vision acuity (BCVA), cup-to-disc ratio (C/D), and mean deviation (MD). Safety was evaluated by adverse events.

RESULTS

Forty eyes from 40 consecutive patients were included with a mean follow-up of 14.8 ± 3.0 months. Circumferential catheterization was successfully conducted in 36 eyes (90%). Mean IOP decreased from 26.2 ± 6.9 mmHg to 14.5 ± 2.7 mmHg at 12 months postoperatively. While medication numbers were reduced from 3.2 ± 0.6 to 0.5 ± 0.8 at month 12 (both p < 0.001). Qualified success rate was 97.2% [95% confidence interval (CI) 0.92-1.03], 86.1% (95% CI 0.74-0.98) and 66.7% (95% CI 0.51-0.83) at 12 months with three criteria. BCVA, C/D and MD did not show progression at 1-year follow-up (p > 0.05). Age, baseline IOP, and spherical equivalent negatively influenced the success rate significantly (all p < 0.05). Adverse events included hyphema (30.6%), IOP spike > 25 mmHg (8.3%), and peripheral synechia to the trabecular-Descemet's membrane (2.7%).

CONCLUSION

Twisted 6/0 suture can be an ideal material for cannulation. Modified suture-assisted canaloplasty is an effective, safe alternative with a cost-efficient feature for patients with POAG, especially in developing countries.

TRIAL REGISTRATION

This trial was registered in the Chinese Clinical Trial Registry ( ChiCTR1900028618 , 29/12/2019).

Canaloplasty and Trabeculotomy Combined with Phacoemulsification for Glaucoma: 12-Month Results of the GEMINI Study

Purpose

To report 12-month efficacy outcomes of 360° canaloplasty and 180° trabeculotomy using the OMNI surgical system in combination with phacoemulsification in patients with mild-moderate open-angle glaucoma (OAG) and visually significant cataract.

Setting

Fifteen multi-subspecialty ophthalmology practices and surgery centers located in 14 US states.

Design

Prospective, multicenter, IRB approved study of patients treated with canaloplasty (360°) and trabeculotomy (180°). Eligible patients had cataract and mild-moderate OAG with intraocular pressure (IOP) ≤33 mmHg on 1 to 4 hypotensive medications. Unmedicated post-washout mean diurnal IOP (DIOP) ≥21 and ≤36 mmHg.

Methods

Medication washout preoperatively and prior to month 12 DIOP. Effectiveness outcomes were IOP and IOP lowering medication use. Safety outcomes included adverse events and secondary surgical interventions (SSIs). Evaluations at 1, 3, 6, and 12 months.

Results

A total of 149 subjects underwent surgery and 120 were included in the final effectiveness analysis. Mean (standard deviation) unmedicated diurnal IOP was reduced from 23.8 (3.1) mmHg at baseline to 15.6 (4.0) at month 12 (−35%) and medications (before washout) were reduced from 1.8 (0.9) at baseline to 0.4 (0.9) at month 12 (−80%). At month 12, 84.2% of eyes achieved IOP reductions >20% from baseline, 80% of eyes were medication-free, and 76% of eyes achieved IOP between 6–18 mmHg inclusive. Adverse events were uncommon. Most were mild and self-limited including transient hyphema (9 of 149; 6%) and transient IOP elevations (3 of 149; 2.0%). No eyes required SSIs or experienced loss of VA that was attributable to the device or procedure.

Conclusion

Canaloplasty and trabeculotomy performed with the OMNI surgical system at the time of phacoemulsification significantly reduces unmedicated mean diurnal IOP and medication use 12 months postoperatively, with an excellent safety profile. This procedure should be considered for eyes with mild-moderate OAG to reduce IOP, medication burden, or both.

Interim Analysis of STREAMLINE® Surgical System Clinical Outcomes in Eyes with Glaucoma

Purpose

To characterize the clinical outcomes of a novel ab interno minimally invasive procedure with the STREAMLINE^® Surgical System for creation of incisional goniotomies and canal of Schlemm viscodilation in eyes with mild to severe primary open-angle glaucoma (POAG).

Methods

In a prospective, single-arm, first-in-human case series, 20 eyes of 20 subjects with mild to severe POAG underwent creation of incisional goniotomies and canal of Schlemm viscodilation following phacoemulsification cataract extraction after washout of all intraocular pressure (IOP)-lowering medications. The angle surgery portion was performed with a single-use handpiece tipped with a microcannula that creates precise goniotomies through the trabecular meshwork into the canal of Schlemm and delivers a small volume of ophthalmic viscosurgical device directly into the canal via precise catheterization. Outcomes in this interim analysis included mean reduction in IOP and medications through 6 months of follow-up, as well as the proportion of eyes achieving IOP reduction ≥20% from baseline.

Results

At month 6, mean IOP reduction of ≥20% from baseline was achieved in 89.5% of eyes (17/19). Mean (standard deviation) medicated IOP at screening was 16.3 (3.6) mmHg and unmedicated baseline IOP (after washout) was 23.5 (2.5) mmHg. Mean IOP was significantly reduced from baseline through 6 months of follow-up to 14.7 (2.4) mmHg (p<0.001), representing an IOP reduction of 8.8 mmHg (36.9%). Overall, 57.9% (11/19) of eyes decreased dependence on IOP-lowering medications by at least one medication, and 42.1% (8/19) were medication free. Mean medication use was reduced from 2.0 (0.8) at screening to 1.1 (1.1) at 6 months (p<0.001). Three eyes had transient IOP spikes treated with topical medications.

Conclusion

The creation of incisional goniotomies and canal of Schlemm viscodilation safely and effectively reduced IOP and the need for IOP-lowering medications by both clinically and statistically significant magnitudes in eyes with mild to severe POAG undergoing concomitant phacoemulsification cataract extraction through the first 6 months of follow-up.

The surgical management of glaucoma: A review

After a long period of little change, glaucoma surgery has experienced a dramatic rise in the number of possible procedures in the last two decades. Glaucoma filtering surgeries with mitomycin C and glaucoma drainage devices remain the standard of surgical care. Other newer surgeries, some of which are minimally or microinvasive glaucoma surgeries, target existing trabecular outflow, enhance suprachoroidal outflow, create subconjunctival blebs, or reduce aqueous production. Some require the implantation of a device such as the iStent, Hydrus, Ex-PRESS, XEN and PRESERFLO, whilst others do not-Trabectome, Kahook dual blade, Ab interno canaloplasty, gonioscopy-assisted transluminal trabeculotomy, OMNI and excimer laser trabeculotomy. Others are a less destructive variation of an established procedure, such as micropulse transscleral cyclophotocoagulation, endoscopic cyclophotocoagulation and ultrasound cycloplasty. Cataract surgery alone can be a significant glaucoma operation. These older and newer glaucoma surgeries, their mechanism of action, efficacy and complications are the subject of this review.

36-month effectiveness of ab-interno canaloplasty standalone versus combined with cataract surgery for the treatment of open-angle glaucoma

PURPOSE

To report the 36-month effectiveness of ab-interno canaloplasty performed with the iTrack microcatheter (Nova Eye Medical, Fremont, USA) as a standalone procedure or combined with cataract surgery.

DESIGN

A single-center, retrospective case series PARTICIPANTS: Eyes diagnosed with primary open-angle glaucoma (POAG).

METHODS

Eyes with POAG were treated with either ab-interno canaloplasty as a standalone procedure (iTrack-alone) or in conjunction with phacoemulsification (iTrack+phaco).

MAIN OUTCOME MEASURES

The main outcome was mean reduction in intraocular pressure (IOP) and number of glaucoma medications at 12, 24, and 36 months postoperatively. Secondary endpoints consisted of visual acuity and the rate of complications.

RESULTS

44 eyes of 44 patients with open-angle glaucoma were included: 23 eyes in the iTrack-alone group and 21 eyes in the iTrack+phaco group. When both groups were analyzed together, both IOP and the number of medications were significantly reduced at 12 months (p<0.0001) and remained stable at 24 and 36 months. IOP decreased from 20.5±5.1 mmHg preoperatively to 13.3±2.1, 13.1±2.4 and 13.3±2.1 mmHg at 12-24-36 months respectively; the number of medications was reduced from 2.8±0.9 preoperatively to 1.1±1.1, 1.0±1.1 and 1.3±1.3 at 12-24 and 36 months postoperatively. Comparable results were observed in the iTrack-alone and iTrack+phaco groups, from a baseline 20.9±6.1 and 20.0±3.9 to 13.2±2.1 and 13.5±2.2 at 36-month respectively. At 36 months, 95.5% of eyes had IOP ≤17 mmHg and 68.2% of eyes were on ≤1 medication. No serious intra-operative or postoperative complications were reported.

CONCLUSION

Ab-interno canaloplasty performed with the iTrack microcatheter was found to be effective in reducing IOP and medication dependence. Comparable results were observed when employed as a standalone procedure or when combined with cataract surgery.

Canaloplasty in the spotlight: surgical alternatives and future perspectives

The modern glaucoma surgeon is faced with many surgical alternatives for the management of glaucoma. In recent years, numerous techniques that make Schlemm's canal (SC) more accessible for surgery by being less invasive and surgically less challenging were introduced. Since its first introduction, canaloplasty has become a well-established method of glaucoma surgery. The aim of this paper was to present an overview of canaloplasty and its modifications, and to highlight their strong points and potential drawbacks based on available data on the effectiveness of each technique. Furthermore, it offered an overview of the development of canaloplasty over time and the clinical aspects that should be considered in patient selection. Abbreviations: ABiC = Canaloplasty ab interno, AH = aqueous humour, CSD = Canaloplasty with suprachoroidal drainage, IOP = intraocular pressure, MIGS = minimally invasive glaucoma surgery, OAG = open angle glaucoma, PEXG = pseudoexfoliation glaucoma, SC = Schlemm's canal, TDM = trabeculo-Descemet's membrane.

Evaluation of the Efficacy and Safety of Canaloplasty and iStent Bypass Implantation in Patients with Open-Angle Glaucoma: A Review of the Literature

The aim of the paper was to evaluate the efficacy and safety of minimally invasive antiglaucoma procedures: Canaloplasty and iStent bypass implantation with and without phacoemulsification in patients with primary open-angle glaucoma (POAG). A systematic review of the recent literature was performed based on the PubMed, Google Scholar, Web of Science and Scopus databases. The effectiveness of the procedures was evaluated based on the reduction of intraocular pressure (IOP) and the amount of antiglaucoma medication used before and after surgery. Safety of the treatments was evaluated based on the number of incidences of certain intraoperative and postoperative complications. Independent prospective randomized controlled trials (PRCTs) have demonstrated that both procedures, canaloplasty and iStent implantation, are effective in reducing IOP and the amount of antiglaucoma medication. Considering the safety profile of these procedures, both canaloplasty and iStent implantation are associated with low rates of postoperative complications and have similar safety profiles. Further studies are needed to confirm the results of our analysis, including a high-quality randomized controlled trial comparing canaloplasty and iStent bypass implantation

Long-term medication reduction in controlled glaucoma with iTrack ab-interno canaloplasty as a standalone procedure and combined with cataract surgery

Purpose:

To evaluate the long-term effectiveness of iTrack (Nova Eye Medical, Fremont, USA) ab-interno canaloplasty performed as a standalone procedure, or combined with cataract surgery, in reducing antiglaucoma medication dependence and maintaining intraocular pressure within target range in patients with controlled primary open-angle glaucoma.

Methods:

This is a retrospective, single-center, case series study of patients who underwent iTrack ab-interno canaloplasty as a standalone procedure (n = 34) or in combination with cataract surgery (n = 11). Eyes with controlled mild or moderate glaucoma (intraocular pressure ⩽17 mmHg) were included; those with prior glaucoma surgeries were excluded. The primary outcome was the mean reduction in glaucoma medication and the secondary outcome was the maintenance of controlled intraocular pressure postoperatively.

Results:

A total of 35 patients (45 eyes) with a mean age of 73 ± 9.7 years were included in the study. For all eyes, a significant decrease (61%) in the mean number of medications was seen at 36 months (1.89 ± 0.93 versus 0.60 ± 0.82; p < 0.001), with 56% (14/25) of eyes medication free. No significant difference was observed in the reduction of medication use whether iTrack was performed with or without cataract surgery at 12 and 36 months. Mean baseline intraocular pressure of 14.42 ± 2.2 mmHg for all eyes was maintained at the 12-, 24-, and 36-month follow-up visits (14.6 ± 3.65, 15.06 ± 2.26, and 14.19 ± 2.91, respectively), with no significant difference between the two groups (p = 0.08).

Conclusion:

The iTrack ab-interno canaloplasty significantly reduced medication dependency and maintained intraocular pressure within target range in patients with controlled mild or moderate primary open-angle glaucoma, while showing a good safety profile, both as a standalone procedure or in combination with cataract surgery.

Efficacy and safety data for the Ab interno XEN45 gel stent implant at 3 Years: A retrospective analysis

PURPOSE

To report efficacy and safety measures of the XEN45 gel stent at 36 months in the UK National Health Service setting.

METHODS

Retrospective non-comparative audit of the records of patients who underwent XEN45 implantation between June 2015 and May 2017 was performed. Main outcome measures were intraocular pressure and number of antihypertensive medications used. Failure was defined as need for further surgery or stent removal. Success was defined as a 20% decrease in intraocular pressure without the need for additional glaucoma medications or a reduction in antihypertensive medications without an increase in baseline intraocular pressure. Needling rates and preoperative factors effect were assessed.

RESULTS

The cohort included 205 patients (205 eyes) with primary open angle glaucoma (84.4%), angle closure glaucoma (7.8%), or refractory glaucoma (7.8%), 62.9% had a stand-alone procedure and 37.1%, a combined phaco-XEN45 procedure. Mean intraocular pressure was 22.6 ± 7.0 mmHg at baseline compared to 14.7 ± 3.8 mmHg at 24 months and 14.0 ± 2.9 mmHg at 36 months (p < 0.001 for both). Mean number of medications used was 2.6 ± 1.1 at baseline compared to 0.5 ± 0.9 and 0.6 ± 1.0, at 24- and 36-months, respectively (p < 0.001 for both). The failure rate at 36 months was 25%. Needling was required in 36.6%. Evaluation of background factors yielded an increased failure rate in non-Caucasians compared to Caucasians (74% vs 21%, p < 0.001).

CONCLUSION

XEN45 implantation is effective and safe at 36 months' follow-up. Patients should be advised regarding the risk of failure and possible need for bleb revisions. Careful patient selection may be required.

24-Month Efficacy of Viscodilation of Schlemm's Canal and the Distal Outflow System with iTrack Ab-Interno Canaloplasty for the Treatment of Primary Open-Angle Glaucoma

PURPOSE

This study aimed to evaluate the 24-month efficacy of viscodilation of Schlemm's canal and the distal outflow system with iTrack ab-interno canaloplasty in reducing intraocular pressure (IOP) and antiglaucoma medication use in patients with primary open-angle glaucoma (POAG).

PATIENTS AND METHODS

This retrospective, comparative, and consecutive case series assessed the 24-month outcomes of iTrack as a standalone procedure (iTrack-alone) or in conjunction with cataract surgery (iTrack+phaco), in cases of mild, moderate or severe POAG. Data were collected at baseline and the 12- and 24-month follow-up visits.

RESULTS

The study included 53 patients (60 eyes) with a mean age of 73.6±9 years. For all eyes, a significant reduction in mean IOP was seen at 12 and 24 months, reducing from 20±4.9 mmHg at baseline to 13.6±1.9 mmHg and 13.5±2.6 mmHg, respectively (P<0.001). The reduction in medications was also significant, reducing to 1.12±1.09 and 1.7±1.29 medications at 12 months and 24 months, respectively, from a baseline of 2.77±0.91 (P<0.001). Similar results were achieved whether iTrack was performed as a standalone procedure, or in conjunction with cataract surgery. While the iTrack-alone group started with a higher IOP at baseline, both groups experienced similar and stable IOP reduction of more than 30% from baseline. The reduction in medication use was also significant in both groups, decreasing from 3±0.7 for iTrack-alone and 2.5±1.1 for iTrack+phaco at baseline to 2.1±1.3 and 1.3±1.2 at 24 months, respectively (P<0.001). The 24-month efficacy outcomes were similar in cases of mild-moderate versus severe glaucoma. No serious adverse events were recorded.

CONCLUSION

Twenty-four-month follow-up data demonstrate that iTrack ab-interno canaloplasty can effectively reduce IOP and medication dependence, with a good safety profile. These results also demonstrate that iTrack can be effectively performed as a standalone procedure or in combination with cataract surgery, and in all grades of glaucoma severity.

The Efficacy of Ab Externo Canaloplasty by Using a Nonabsorbable Suture and No Viscoelastics; IOP Results, Intraoperative and Early Complication Rates within 6-Month Follow-Up Period

BACKGROUND

To report the efficacy of ab externo canaloplasty by exclusively using only a nonabsorbable suture as a standalone operation or combined with phacoemulsification in terms of mean intraocular pressure (IOP), medication reduction, and intra- and postoperative complication rates as well as additional glaucoma surgery.

PATIENTS AND METHODS

Forty-eight patients with primary open-angle glaucoma (POAG) and 50 eyes were divided into two groups according to the operation performed (Group A canaloplasty, n = 34 and Group B canaloplasty combined with phaco, n = 16), respectively. The success criteria were evaluated between three IOP ranges: a) IOP ≤ 16 mmHg, b) ≤ 18 mmHg, and c) ≤ 21 mmHg. Complete success was considered the percentage of eyes reaching these goals with no medication and qualified success with or without medication. Groups A and B were compared with the Kaplan-Meier test. Mean IOP and medication reduction as well as additional glaucoma surgery were also evaluated. The follow-up time was 6 months. Statistical importance was given at p < 0.05.

RESULTS

Fail rate and intraoperative conversion of canaloplasty to other surgery (trabeculotomy due to extensive cheese-wiring) accounted for 12% (6 eyes), while a mandatory usage of the iTrack 250A microcatheter to successfully overcome intracanalicular bridging of the Schlemm's canal accounted for 20% (10 eyes). The most common early postoperative complications in both groups were hyphema, cheese wiring, and transient IOP rising. The mean IOP in Group A reduced from 23.67 ± 6.06 mmHg to 13.35 ± 4.23 mmHg and in Group B, it reduced from 23.55 ± 6.19 mmHg to 12.75 ± 1.5 mmHg at 6 months (p < 0.001). Group A's absolute success rates accounted for a) 44%, b) 47.1%, and c) 52.9% in comparison to Group B [a) 50%, b) 50%, and c) 56.3%] at 6 months (p < 0.05). Qualified success with or without medication showed no statistical differences between the groups. The mean medication reduction was significantly lower (p < 0.001) in both groups (Group A from baseline 3.2 ± 1.23 to 0.95 ± 1.35 and Group B from 3.12 ± 0.88 to 1.12 ± 0.75 at 6 months, respectively). Five eyes (10%) required additional glaucoma surgery.

CONCLUSIONS

Ab externo canaloplasty by exclusively using only a nonabsorbable suture as a standalone operation or combined with phacoemulsification seems to lower the mean IOP and medication sufficiently. However, they pose a greater surgical challenge and intraoperative complication rate. Additional glaucoma surgery or medication following both procedures may be necessary to achieve an optimal target IOP.

Microinvasive Glaucoma Surgery: A Review of Schlemm's Canal-Based Procedures

Microinvasive glaucoma surgery has gained popularity over the past decade. It can be performed using three different mechanisms. In the present review, we focused on Schlemm’s canal (SC)-based surgery, which increases aqueous humor (AH) outflow into the aqueous veins by either removal of the trabecular meshwork (TM) or an increase in the tension in the TM. In primary open-angle glaucoma (POAG), the TM is the most likely region for increased AH outflow resistance. Theoretically, removal of the TM can improve the AH outflow; hence, glaucoma specialists focus on microsurgical dissection of the TM. In this review, we analyzed the available literature to examine SC-related microsurgical modalities based on the histopathological proofs of the localization of resistance of the AH outflow. First, we considered the role, anatomy, and physiology of the TM and SC. We referred to studies that describe the mechanisms and potential pathways, related to increased intraocular pressure in the POAG, that are targeted using the SC-related microsurgical interventions. Next, we took a closer look at the gonioscopic tools necessary for an ab-interno approach and explored incision canal surgery: ab-interno trabeculectomy using different instrumentation (Trabectome^®, Kahook Dual Blade) and variations of the technique. Thereafter, we discussed ab-interno canaloplasty, explaining the technique and reviewing its effectiveness. Finally, we presented the scope for future research in the field. Although the iStent also targets SC by bypassing it, this device has been reviewed extensively elsewhere.

12-month interim results of a prospective study of patients with mild to moderate open-angle glaucoma undergoing combined viscodilation of Schlemm's canal and collector channels and 360° trabeculotomy as a standalone procedure or combined with cataract surgery

PURPOSE

To characterize clinical outcomes of combined viscodilation of Schlemm's canal and collector channels and 360° trabeculotomy as a standalone procedure or combined with cataract surgery in eyes with mild to moderate open-angle glaucoma (OAG).

METHODS

In this prospective case series, the OMNI glaucoma surgical platform (Sight Sciences, Menlo Park, CA) was utilized to perform the procedure either combined with phacoemulsification or as a standalone procedure. Changes from baseline in intraocular pressure (IOP) and IOP-lowering medications were evaluated through the first 12 months of a planned 24-month follow-up period.

RESULTS

Among 17 eyes of 15 subjects, mean IOP was reduced from 20.4 mmHg to 12.7-13.7 mmHg through 12 months of follow-up (p < 0.001 at every time point) and mean medications reduced from 2.5 to 0.1-0.6 (p < 0.001 at every time point). IOP reductions in eyes undergoing standalone surgery were approximately 2-4 mmHg greater at each time point compared to eyes undergoing surgery combined with phacoemulsification; this may be related to a higher baseline IOP in the former eyes (22.1 vs 18.5 mmHg). Six eyes developed hyphema, of which three required washout for elevated IOP on the first postoperative day; six additional eyes had IOP elevations that resolved with medical management.

CONCLUSION

Viscodilation of Schlemm's canal and collector channels paired with ab interno trabeculotomy performed with a single integrated instrument (OMNI), whether as standalone or combined with phacoemulsification, effectively lowers both IOP and the need for IOP-lowering medications through 12 months of follow-up.

Safety profile of minimally invasive glaucoma surgery

PURPOSE OF REVIEW

This article reviews the safety profile of trabecular meshwork/Schlemm's canal-based, subconjunctival, and suprachoroidal minimally invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Prospective randomized clinical trials and metaanalyses published during the 2019-2020 review period provided important data regarding the safety profile of trabecular meshwork/Schlemm's canal-based MIGS. Transient hyphema and intraocular pressure spikes are among the most common complications associated with this category of MIGS, but more serious adverse events such as cyclodialysis cleft formation may also occur. Trabecular bypass microstents and the intracanalicular scaffold are further subject to device-related complications, including malposition and obstruction. Recent case reports and retrospective case series have further characterized the safety profile of the subconjunctival gel stent, with adverse events ranging from self-limited hypotony to visually devastating endophthalmitis and suprachoroidal hemorrhage. Five-year results of the COMPASS XT study demonstrated significantly greater endothelial cell loss in patients randomized to receive CyPass Micro-Stent (Alcon Laboratories, Fort Worth, TX, USA) in combination with cataract surgery versus those who underwent cataract surgery alone, and ultimately led to a Food and Drug Administration Class I recall of the device.

SUMMARY

Trabecular meshwork/Schlemm's canal-based procedures are generally among the safest MIGS, with mostly self-limited and nonvision-threatening complications. Subconjunctival gel stent insertion is associated with both bleb-related and stent-specific adverse events, which are similar to those observed with trabeculectomy and tube shunt surgery, respectively. Removal of the CyPass Micro-Stent from the market underscores the need for high-quality, long-term safety data regarding MIGS.

Canaloplasty and Trabeculotomy Combined with Phacoemulsification in Open-Angle Glaucoma: Interim Results from the GEMINI Study

PURPOSE

To report interim 6-month safety and efficacy outcomes of 360° canaloplasty and 180° trabeculotomy using the OMNI® Surgical System concomitantly with phacoemulsification in patients with open-angle glaucoma (OAG).

SETTING

Fifteen multi-subspecialty ophthalmology practices and surgery centers located in 14 states (Alabama, Arizona, Arkansas, Florida, Georgia, Iowa, Kansas, Montana, Nebraska, North Dakota, Oklahoma, Pennsylvania, Texas, and Wisconsin).

DESIGN

Prospective, multicenter, IRB approved study of patients treated with canaloplasty (360°) and trabeculotomy (180°). Eligible patients had cataract and mild-moderate OAG with intraocular pressure (IOP) ≤33 mmHg on 1 to 4 hypotensive medications.

METHODS

Medication washout prior to baseline diurnal IOP (Goldmann). Effectiveness outcomes included mean IOP and medications. Safety outcomes included adverse events (AE), best corrected visual acuity (BCVA) and secondary surgical interventions (SSI). Analysis includes descriptive statistics and t-tests evaluating change from baseline.

RESULTS

A total of 137 patients were enrolled and treated. Mean diurnal IOP after washout was 23.8 ± 3.1 mmHg at baseline. At month 6, 78% (104/134) were medication free with IOP of 14.2 mmHg, a mean reduction of 9.0 mmHg (38%). 100% (104/104) had a ≥ 20% reduction in IOP and 86% (89/104) had IOP ≥6 and ≤18 mmHg. The mean number of medications at screening was 1.8 ± 0.9 and 0.6 ± 1.0 at month 6. AE included transient hyphema (4.6%) and IOP elevation ≥10 mmHg (2%). There were no AE for loss of BCVA or recurring hyphema. There were no SSI.

CONCLUSION

Canaloplasty followed with trabeculotomy and performed concomitantly with phacoemulsification has favorable intra and perioperative safety, significantly reduces IOP and anti-glaucoma medications through 6 months in eyes with mild-moderate OAG.

Canaloplasty ab interno (AbiC) - 2-Year-Results of a Novel Minimally Invasive Glaucoma Surgery (MIGS) Technique

PURPOSE

The aim of this study is to evaluate the long-term efficacy of a novel minimally invasive glaucoma surgery technique (MIGS), Ab interno Canaloplasty (AbiC).

MATERIAL AND METHODS

For this retrospective cohort study, we analysed the data of 25 eyes of 23 patients with open angle glaucoma who underwent an AbiC (6 eyes) or in case of an additional cataract, a combined cataract-AbiC procedure ("phacocanaloplasty ab interno", 19 eyes), respectively. Postoperatively, we investigated the intraocular pressure (IOP) and the number of still required IOP-lowering medication, as well as surgery-related complications.

RESULTS

Overall, the mean baseline IOP of 20.24 mmHg ± 5.92 (n = 25) was reduced to 10.64 mmHg ± 2.77 (n = 25, p < 0.001), 12.55 mmHg ± 3.33 (n = 22, p < 0.001) and 13.67 mmHg ± 2.15 (n = 21, p < 0.001) at 1 day, 1 year and 2 year follow-up visit, respectively. Compared to baseline, this implies a reduction in IOP of 47.4, 37.9 and 32.5%. An average glaucoma medication usage of 1.92 ± 1.04 was registered at baseline visit and was reduced to 0,05 ± 0,23 after 2 years of follow-up. 80% of patients were off medication. In 5 eyes (20%) further antiglaucomatous eye drops or surgical treatment were administered. The only surgical complications were hyphema in 5 eyes (20%) and a localized peripheral detachment of the Descemet's membrane in one eye (4%) with no late sequelae.

CONCLUSION

AbiC performed independently or combined with cataract surgery seems to be a safe and effective MIGS-technique with good long-term regulation of IOP and low risk profile.

A novel suprachoroidal microinvasive glaucoma implant: in vivo biocompatibility and biointegration

Background

A major challenge for any glaucoma implant is their ability to provide long-term intraocular pressure lowering efficacy. The formation of a low-permeability fibrous capsule around the device often leads to obstructed drainage channels, which may impair the drainage function of devices. These foreign body-related limitations point to the need to develop biologically inert biomaterials to improve performance in reaching long-term intraocular pressure reduction. The aim of this study was to evaluate in vivo (in rabbits) the ocular biocompatibility and tissue integration of a novel suprachoroidal microinvasive glaucoma implant, MINIject™ (iSTAR Medical, Wavre, Belgium).

Results

In two rabbit studies, no biocompatibility issue was induced by the suprachoroidal, ab-externo implantation of the MINIject™ device. Clinical evaluation throughout the 6 post-operative months between the sham and test groups were similar, suggesting most reactions were related to the ab-externo surgical technique used for rabbits, rather than the implant material itself. Histological analysis of ocular tissues at post-operative months 1, 3 and 6 revealed that the implant was well-tolerated and induced only minimal fibroplasia and thus minimal encapsulation around the implant. The microporous structure of the device became rapidly colonized by cells, mostly by macrophages through cell migration, which do not, by their nature, impede the flow of aqueous humor through the device. Time-course analysis showed that once established, pore colonization was stable over time. No fibrosis nor dense connective tissue development were observed within any implant at any time point. The presence of pore colonization may be the process by which encapsulation around the implant is minimized, thus preserving the permeability of the surrounding tissues. No degradation nor structural changes of the implant occurred during the course of both studies.

Conclusions

The novel MINIject™ microinvasive glaucoma implant was well-tolerated in ocular tissues of rabbits, with observance of biointegration, and no biocompatibility issues. Minimal fibrous encapsulation and stable cellular pore colonization provided evidence of preserved drainage properties over time, suggesting that the implant may produce a long-term ability to enhance aqueous outflow.

Microinvasive glaucoma surgery: A review of 3476 eyes

Microinvasive glaucoma surgery (MIGS) is a potentially safer and more efficacious method studied in patients with mild-to-moderate open-angle glaucoma requiring less invasive treatment goals; however, the literature on MIGS must be thoroughly evaluated. We conducted a review of MIGS by searching MEDLINE, EMBASE, and Cochrane CENTRAL. Primary efficacy indicators were reductions in intraocular pressure and topical medication use postoperatively. While all comparative randomized controlled trials assessing MIGS in English peer-reviewed journals were included, only observational studies with a target follow-up of at least one year and a high priority score were analyzed, resulting in a total of 3476 eyes across 20 trials. The mean age was 69.5 ± 2.9 years, 53.7% were female, and 77.4% were Caucasian. One study had last follow-up at less than one year, fifteen studies had follow-up extending 1-2 years, and four had longer than two years of follow-up. A pattern of more significant intraocular pressure and medication reduction was observed in patients who underwent MIGS (n = 2170) relative to control (n = 1306) interventions. iStent had the most literature supporting its efficacy, followed by Hydrus. The most common adverse events after MIGS implantation included stent obstruction, inflammation, and subsequent surgical intervention. Surgical complication rates and efficacy are favorable after MIGS. This review helps to consolidate the high-quality evidence that exists for various MIGS procedures and to identify gaps where further research is needed.

Combined Gonioscopy-Assisted Transluminal Trabeculotomy (GATT) with Ab Interno Canaloplasty (ABiC) in Conjunction with Phacoemulsification: 12-Month Outcomes

Purpose

To report the surgical outcomes of combined gonioscopy-assisted transluminal trabeculotomy (GATT) with ab interno canaloplasty (ABiC) in conjunction with phacoemulsification for primary open-angle glaucoma (POAG).

Patients and Methods

This prospective, interventional, non-comparative case series included POAG patients who underwent combined GATT and ABiC in conjunction with phacoemulsification performed between January 2018 and August 2018. Main outcome measures include surgical success rate, changes in intraocular pressure (IOP), number of antiglaucoma medications, corrected distance visual acuity (CDVA), and complications.

Results

We enrolled twenty eyes of 19 patients in our study. The mean age was 61.2 ± 6 years, and all the patients completed a 12-month follow-up. The overall success rate was 100%. The mean baseline IOP was 19.75 ± 4.68 mmHg, and at 12 months, the mean IOP was 13.30 ± 1.30 mmHg (IOP reduction of 32.7%). The baseline number of antiglaucoma medications was 3.4 ± 0.6 (range: 2 to 4 medications), and after 12 months follow-up, the number was reduced to 1.1 ± 1.0 (range: 0 to 2 medications). The CDVA for all 20 eyes was 0.85±0.58 LogMAR at baseline, and 0.16±0.30 LogMAR at 12-month follow-up. Only six eyes developed hyphaema, which had cleared by the first postoperative month, and three eyes needed medical treatment for postoperative IOP spikes.

Conclusion

The 12-month results of our study suggest that combined GATT with ABiC in conjunction with phacoemulsification is a safe and effective alternative in decreasing the IOP and number of antiglaucoma medications in POAG patients.

Mini-canaloplasty as a modified technique for the surgical treatment of open-angle glaucoma

Authors present a modified surgical technique for canaloplasty without preparing the classical trabeculo-Descemet’s membrane (TDM) and having to close sutures. Twelve patients with open-angle glaucoma (OAG) (aged 58–77 years) received the modified technique, which does not require the deep scleral flap to be excised, an intrascleral lake to be created, or TDM dissection. After accessing the Schlemm’s canal (SC), cannulation and placement of the sutures are made similar to those in the classical canaloplasty. The conjunctiva is closed via bipolar diathermy. The mean intraocular pressure (IOP) before surgery was 18.0 ± 8 mmHg, and the mean number of anti-glaucoma medications taken was 3 ± 1. Mean IOP at the end of the observation period (18.0 ± 6.0 months) was reduced by 23% (15.5 ± 4.1 mmHg), while the mean number of medications taken was reduced to 0.25 ± 1.0. In all eyes, the SC was successively opened, with no cheese-wiring. Adverse events included microhyphaema, mild corneal oedema, and folds in the TDM. The eyes recovered spontaneously within a few days after the procedure. The mini-canaloplasty technique may reduce the risk of complications associated with classical canaloplasty while effectively lowering the IOP in patients with OAG.

Visual outcomes of combined cataract surgery and minimally invasive glaucoma surgery

Minimally invasive glaucoma surgery (MIGS) has become a reliable standard of care for the treatment of glaucoma when combined with cataract surgery. This review describes the MIGS procedures currently combined with and without cataract surgery with a focus on visual outcomes based on the literature and the experience of the ASCRS Glaucoma Clinical Committee.

Minimally Invasive Glaucoma Surgery: Where Is the Evidence?

PURPOSE

The last decade has witnessed an unprecedented growth in glaucoma treatment options through the introduction of minimally invasive glaucoma surgeries (MIGS). The aim of the present review is to provide an understanding of the currently available MIGS and to examine what data are currently available to guide treatment choice.

DESIGN

Meta-analysis and systematic review of randomized and non-randomized control trials.

METHODS

Out of 2567 articles identified, a total of 77 articles were retained for analysis, including 28 comparative studies and 12 randomized control trials. Overall, 7570 eyes were included. When data permitted, the weighted mean difference in intraocular pressure reduction was calculated for comparison purposes.

RESULTS

Weighted mean intraocular pressure reductions from all analyzed studies were: 15.3% (iStent), 29.1% (iStent inject), 36.2% (ab interno canaloplasty), 34.4% (Hydrus), 36.5% (gonioscopically-assisted transluminal trabeculotomy), 24.0% (trabectome), 25.1% (Kahook dual blade), 30.2% (Cypass), 38.8% (XEN), and 50.0% (Preserflo).

CONCLUSIONS

One of the advantages of the heterogenous range of available MIGS options is the chance to tailor therapy in an individualized manner. However, high-quality data are required to make this choice more than an educated guess. Overall, this review confirms the efficiency of assessed MIGS compared with standalone phacoemulsification, but it highlights that only few studies compare different MIGS techniques and even fewer assess MIGS against criterion standard treatments. Current evidence, while non-negligible, is mostly limited to heterogenous nonrandomized studies and uncontrolled retrospective comparisons, with few quality randomized control trials. We suggest that future research should be comparative and include relevant comparators, standardized to report key outcome features, long-term to assess sustainability and late complications, and ideally randomized.

Canaloplasty in the Treatment of Primary Open-Angle Glaucoma: Patient Selection and Perspectives

Canaloplasty is a surgical procedure that has undergone a number of developments since its introduction in 2005. Many thousands of canaloplasties have been performed around the world since then and is, by definition, a blebless procedure. It does not necessitate the use of any antifibrotic agents and results in safe and effective IOP reductions in patients with open-angle glaucoma (OAG) with minimal complications and no bleb-related adverse events. When considering the surgical management of patients with early and medium stages of the disease, canaloplasty can be considered as a first line option. This paper will overview the theoretical effectiveness of canal surgery, the fundamental aspects of aqueous outflow resistance with particular emphasis on the role of the trabecular meshwork, Schlemm's canal, and the collector channels, and the methods available for the clinical evaluation of the outflow pathways in relation to the ocular anatomy. Further, the paper will detail the surgical technique itself and how this has developed over time together with the clinical aspects that should be accounted for when selecting patients for this surgery.

An Update on Microinvasive Glaucoma Surgery Concurrent With Cataract Extraction

Purpose of Review

In this article, we review the current options for microinvasive glaucoma surgery (MIGS) combined with cataract extraction in the USA and the efficacy of the various approaches.

Recent Findings

MIGS is a rapidly growing area of research and clinical interest. Available surgeries aim to reduce intraocular pressure by improving aqueous outflow through the trabecular or subconjunctival pathways or by reducing aqueous production.

Summary

Multiple approaches to MIGS are utilized in clinical practice. On average, these surgeries are safe and modestly effective in reducing intraocular pressure. Future research will demonstrate which surgical approaches are most efficacious, whether and how to combine MIGS, and the role of MIGS in improving patient quality of life.

Micro-invasive glaucoma surgery - an interventional glaucoma revolution

The glaucoma surgical landscape has changed dramatically over the last decade with the introduction and integration of micro-invasive glaucoma surgery (MIGS) techniques. These modalities target physiologic outflow pathways or optimize previously utilized glaucoma surgical methods in order to deliver safety, efficacy, and individualized care to the patient. MIGS techniques can be classified based on anatomical location as well as method of intraocular pressure (IOP) reduction. This review will focus on MIGS optimizing the conventional outflow pathway via intervention at Schlemm’s canal, MIGS optimizing the uveoscleral outflow pathway via suprachoroidal shunting, and MIGS optimizing the transscleral or subconjunctival outflow pathway which has long been utilized by glaucoma surgeons performing traditional filtration procedures. The wide array of currently available MIGS modalities can be staggering to the glaucoma care provider, but an understanding of the landscape and the large classes of interventional strategies can allow for clinical decision making based on the specifics of the patient’s needs and the pathophysiology of their disease.

Circumferential viscodilation of Schlemm's canal for open-angle glaucoma: ab-interno vs ab-externo canaloplasty with tensioning suture

Purpose

To compare the efficacy of minimally invasive ab-interno canaloplasty (ABiC) vs ab-externo canaloplasty (CP) in reducing intraocular pressure (IOP) and glaucoma medication dependence.

Patients and methods

This nonrandomized, retrospective, single-center, paired eye study assessed the 12-month outcomes of 12 patients with primary open-angle glaucoma who underwent ABiC in one eye and CP in the other eye, either as stand-alone procedures or combined with cataract extraction. Primary endpoints included mean IOP and number of glaucoma medications at 12 months postoperative. Secondary endpoints included surgical complications and secondary interventions.

Results

Four males and eight females with a mean age of 73.8±12.6 years were included. In the CP group, the mean preoperative IOP was 18.1±3.9 mmHg on 2.4±0.5 medications, which reduced to 13.5±2.2 mmHg (P<0.05) on 0.9±0.9 medications (P<0.001). In the ABiC group, the mean preoperative IOP was 18.5±3.4 mmHg on 2.4±0.5 medications and postoperative IOP was 13.8±2.2 mmHg (P<0.05) on 0.8±0.8 medications (P<0.05). There was no significant difference in IOP and medication use between treatment groups at 12 months postoperative. No serious adverse events were recorded in either group, though two patients in the CP group developed pressure spikes 10 mmHg beyond preoperative IOP.

Conclusion

This paired eye study found ABiC to have comparable IOP lowering and glaucoma medication reduction to CP in open-angle glaucoma. This suggests ABiC may be a suitable method for improving aqueous outflow via the trabecular pathway. Further large-scale investigation is needed.