Treatment of Open-Angle Glaucoma with iStent Implantation Combined with Phacoemulsification in Polish Caucasian Population

7-Year Efficacy and Safety of iStent inject Trabecular Micro-Bypass in Combined and Standalone Usage

INTRODUCTION

This study evaluated 7-year effectiveness and safety of second-generation trabecular micro-bypass implantation (iStent inject) either in combination with cataract surgery or as a standalone procedure (Combined or Standalone subgroups, respectively) in eyes with open-angle glaucoma.

METHODS

This prospective, non-randomized, unmasked, longitudinal study included 125 consecutive iStent inject cases of a single surgeon at a large German academic hospital. Patients had considerable preoperative disease burden, with mean intraocular pressure (IOP) of 23.5 mmHg, 84.8% of eyes on ≥ 2 medications, and 38.4% of eyes with prior glaucoma surgery. IOP, medications, adverse events, and secondary surgeries were assessed through 7 years in the Overall cohort and in Combined (n = 81) and Standalone (n = 44) subgroups.

RESULTS

Over 7-year follow-up, mean IOP decreased by 36.2-40.0% in Overall eyes, 34.1-38.9% in Combined eyes, and 39.5-43.5% in Standalone eyes (p < 0.001 at all timepoints for all groups). Meanwhile, mean medications decreased by 59.3-71.3% in Overall eyes, 57.9-69.0% in Combined eyes, and 62.1-76.2% in Standalone eyes (p < 0.001 at all timepoints in all groups). At last follow-up (mean 77.4 months; 92.8% of patients with last visit at 6 or 7 years), 83.7% of Overall eyes, 82.3% of Combined eyes, and 86.4% of Standalone eyes had achieved ≥ 20% IOP reduction vs preoperative. At last follow-up vs preoperative, 100% of eyes in all groups had the same or lower IOP and 100% had the same or lower medication regimen. Safety outcomes were favorable, with no filtration surgeries and only 4.84% of eyes experiencing clinically significant visual field loss over 7 years of follow-up.

CONCLUSION

iStent inject implantation with or without phacoemulsification produced significant and durable 7-year reductions in IOP (~ 34-44% reduction) and medications (~ 58-76% reduction) while preventing filtering surgery in this cohort of patients with relatively high preoperative disease burden. Combined and Standalone cases had similarly favorable effectiveness and safety.

First-Generation iStent Bypass Implantation versus ab Externo Canaloplasty Combined with Phacoemulsification in Patients with Primary Open Angle Glaucoma-12-Month Follow-Up

This prospective, non-randomized, interventional clinical study evaluated the efficacy and safety profile of first-generation iStent bypass implantation versus ab externo canaloplasty, both combined with phacoemulsification, in patients with primary open-angle glaucoma (POAG) after 12-month follow-up. A total of 138 patients with POAG and their 138 eyes (69 phaco-iStent and 69 phacocanaloplasty) were included. Postoperatively at 12 months, the mean intraocular pressure (IOP) decreased from 18.44 ± 3.88 to 15.51 ± 2.50 mmHg and from 17.20 ± 4.04 to 14.97 ± 2.37 mmHg in the phaco-iStent (PiS) and phacocanaloplasty (PC) groups, respectively (p = 0.480). In both groups, 35.7% achieved >20% IOP reduction from baseline. A total of 86% and 71.4% of the eyes were medication-free at 12 months in the PiS and PC groups, respectively. In both groups, all eyes showed improvement in best-corrected visual acuity compared with baseline and demonstrated similar safety profiles throughout the 12-month follow-up period. This study showed equal hypotensive effects of PiS and PC. Both procedures significantly reduced the IOP and the requirement for IOP-lowering medications for at least 12 months postoperatively, with no significant differences between the groups.

Efficacy and Safety of ab Externo Phaco-Canaloplasty versus First-Generation iStent Bypass Implantation Combined with Phacoemulsification in Patients with Primary Open Angle Glaucoma-Early Results

This study evaluated the early outcomes of the hypotensive efficacy and safety profile of ab externo phaco-canaloplasty versus first-generation iStent bypass implantation combined with phacoemulsification in patients with primary open-angle glaucoma (POAG). In total, 82 patients with POAG comprising 92 eyes were divided into phaco-canaloplasty (Group PC, (n = 47) or iStent combined with phacoemulsification (Group PiS, n = 45) groups. Primary outcome measures were intraocular pressure (IOP) reduction and number of glaucoma medications. Secondary outcome measures were best-corrected visual acuity (BCVA), endothelial cell density (EECD), changes in anterior chamber depth (ACD), and complication rate. The follow-up period was approximately 6 months. Preoperative IOPs were 17.30 (15.00; 19.85) mmHg and 17.50 (15.10; 20.90) mmHg in the PC and PiS groups, respectively (p = 0.876). At the end of the follow-up, IOP decreased to 15.00 (13.00; 16.00) mmHg and 15.00 (14.00; 17.00) mmHg in the PC and PiS groups, respectively (p = 0.438). Medication usage decreased from 2.08 to 0.12 and 1.40 to 0.04 in PC and PiS eyes, respectively. Most patients in both groups were medication-free at 6 months follow-up. After 6 months of observation, EECD in PC and PiS groups decreased from 2309.50 (2032.00; 2533.00) to 1966.50 (1262.00; 2353.50) and 2160.00 (1958.50; 2372.50), to1231.00 (1089.00; 2050.00), respectively (p = 0.037). Pre-surgery BCVA was 0.80 (0.50; 1.00) and 0.60 (0.40; 1.00) in PC and PiS eyes, respectively (p = 0.456). Follow-up BCVA was 0.95 (0.60; 1.00) for PC and 1.00 (1.00; 1.00) for PiS. Hyphema and corneal oedema were noted on the first day post-surgery in both groups. Subsequent complications included a transient increase in IOP in the PC group. Phaco-canaloplasty and iStent bypass implantation combined with phacoemulsification significantly lowered IOP and decreased medication burden. All eyes in both groups maintained or exhibited improved BCVA relative to baseline. Both surgeries had low postoperative complication rates and exhibited comparable safety profiles over 6-month follow-up in patients with POAG.

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.

Multicenter Effectiveness and Disease Stability Through 3 Years After iStentTrabecular Micro-Bypass with Phacoemulsification in Glaucoma and Ocular Hypertension

Purpose

To evaluate 3-year safety and efficacy of two second-generation trabecular micro-bypass stents. (iStent inject^®) with phacoemulsification.

Materials and Methods

This multicenter retrospective study of iStent inject implantation with phacoemulsification included data from eight surgeons across Australia. Eyes with cataract and mild to advanced glaucoma [predominantly primary open-angle (POAG), primary angle closure (PAC), or normal-tension (NTG) glaucoma] or ocular hypertension (OHT) were included. Study assessments included intraocular pressure (IOP); number of ocular hypotensive medications; proportions of eyes with 0, 1, 2, or ≥3 IOP-lowering medications; IOP ≤15 mmHg or ≤18 mmHg; visual fields (VF); retinal nerve fiber layer thickness (RNFL); central corneal thickness (CCT); intraoperative complications; adverse events; and secondary surgeries.

Results

A total of 273 eyes underwent surgery and had 36-month follow-up. At 36 months versus preoperative, mean IOP decreased by 15.5% (16.4±4.6 mmHg to 13.9±3.5 mmHg; p<0.001), and 70.3% of eyes achieved IOP of ≤15 mmHg (versus 49.1% preoperatively; p<0.001). The mean medication burden decreased by 68.5% (from 1.51±1.17 to 0.48±0.89 medications; p<0.001); 71.4% of eyes were medication-free (versus 21.6% preoperatively; p<0.001), while 6.2% of eyes were on ≥3 medications (versus 22.3% preoperatively; p<0.001); 96.3% of eyes maintained or reduced medications vs preoperative. Significant IOP and medication reductions occurred across glaucoma subtypes (POAG, PAC, NTG, OHT): 13–22% for IOP (p<0.05 for all) and 42–94% for medication (p<0.05 for all). Favorable safety included few adverse events; stable VF, RNFL, and CCT; and filtering surgery in only 8 eyes (2.9%) over 3 years.

Conclusion

In this multicenter cohort from 8 surgeons across Australia, significant IOP and medication reductions were sustained through 3 years after iStent inject implantation with phacoemulsification. Results were favorable across different glaucoma subtypes (including POAG, PAC, NTG, OHT), severities, and surgeons, thereby underscoring the real-world relevance and efficacy of iStent inject implantation for glaucoma treatment.

Efficacy of Selective Laser Trabeculoplasty after iStent Implantation in Primary Open-Angle Glaucoma

iStent implantation is thought to augment the trabecular outflow channel in the anterior segment of the eye. We hypothesized that iStent with subsequent selective laser trabeculoplasty (SLT) would better control the intraocular pressure (IOP) compared to standalone SLT in patients with primary open-angle glaucoma (POAG). We, therefore, determined if the presence of an iStent combined with SLT was statistically associated with IOP lowering compared to standalone SLT. Through retrospective electronic medical record review, records of 824 eyes from 440 patients who received primary SLT without a history of iStent were considered. Additionally, 42 eyes from 28 patients who received SLT after combined phacoemulsification and iStent implantation that failed to control intraocular pressure (IOP) and/or the progression of the disease were retrospectively reviewed. IOP and number of medications, which were tracked in each patient for up to 12 months post laser, were also examined. Successful outcome was defined as a statistically significant reduction in IOP or number of medications at 6 months. As defined in univariate analysis (p ≤ 0.01), multivariate analysis included iStent, age, sex, race, and initial IOP as variables. IOP reduction was statistically associated with patients pre-SLT IOP (p < 0.001) but not with patients with iStent (p = 0.222). Medication reduction was statistically associated with the pre-SLT number of medications (p < 0.001) and iStent (p < 0.001). In eyes that received SLT, iStent was not statistically associated with a greater reduction in IOP compared to controls, but was associated with a higher reduction in the overall number of medications used 6 months after receiving SLT. The work presented should guide clinicians to consider SLT as an effective therapy after iStent implantation, in terms of glaucoma medication reduction in iStent patients, but clinicians should know that the presence of an iStent does not necessarily make subsequent SLT more effective at lowering IOP.