The Effectiveness of First-Generation iStent Microbypass Implantation Depends on Initial Intraocular Pressure: 24-Month Follow-Up-Prospective Clinical Trial

Comparison of Phacoemulsification Alone and With Trabecular Microbypass Stent in Primary Open-Angle Glaucoma and Normal-Tension Glaucoma: An 18-Month Outcome Study

iStent (Glaukos, San Clemente, CA, USA), a minimally invasive glaucoma device, reduces intraocular pressure (IOP) by enhancing aqueous humor outflow when implanted into Schlemm's canal. Although it has demonstrated effectiveness in lowering IOP and slowing glaucoma progression, its applicability to the Taiwanese population, known for a higher incidence of normal-tension glaucoma (NTG) cases, requires validation. This retrospective case-control study, conducted from January 2018 to December 2020, aimed to assess the effectiveness of combining first-generation iStent with phacoemulsification (phaco-iStent) compared to phacoemulsification alone in Taiwanese patients diagnosed with primary open-angle glaucoma (POAG) and NTG, involving 71 eyes (iStent group: POAG 16 and NTG 8; control group: POAG 28 and NTG 19). The primary outcomes included changes in IOP and the number of antiglaucoma medications, with subgroup analyses for POAG and NTG. Over the 18-month follow-up, the iStent group achieved a significantly greater reduction in antiglaucoma medications compared with the control group (p value = 0.003∼<0.001) without significant IOP rebound. After adjusting for confounding factors, the reduction in the number of antiglaucoma medications with iStent remained significant (β = -0.8, p < 0.001) according to the generalized estimating equation. At 18 months, the iStent group demonstrated higher qualified and complete success rates than the control group (73.3% vs. 16.7%, p value = 0.001% and 53.3% vs. 0%, p value = 0.002, respectively). Notably, the NTG-iStent subgroup achieved the highest complete success rate (85.7% at 18 months). In conclusion, phaco-iStent emerges as an effective standalone treatment for Taiwanese patients with POAG and NTG, providing substantial IOP reduction and higher success rates, especially in NTG cases. These findings propose that phaco-iStent could be a promising intervention for managing POAG and NTG within the Taiwanese population. Trial Registration: ClinicalTrials.gov identifier: NCT06630546.

Minimally invasive bleb surgery versus minimally invasive glaucoma surgery: a 12-month retrospective study

This study aimed to compare the IOP-lowering effectiveness and safety of standalone Preserflo MicroShunt and iStent 1st generation implantation combined with phacoemulsification in Caucasian patients with a 12-month follow-up period. This retrospective study analyzed the medical histories of patients undergoing antiglaucoma surgery at the Department of Ophthalmology, Medical University of Bialystok, between January 2019 and January 2022. The main outcome measures were success rates (complete: proportion of eyes with IOP < 18 mmHg (criterion A) and < 15 mmHg (criterion B) or 20% reduction in IOP without any glaucoma medication; qualified: proportion of eyes achieving IOPs < 18 mmHg and < 15 mmHg or 20% reduction in IOP from baseline with or without medications), mean reduction (%) in IOP, medication burden, number of complications and additional interventions. In both groups, a significant decrease in IOP and medication burden were observed at 6 and 12 months when compared with baseline. At 12 months, qualified surgical success in criterion A was recorded in 67.4% and 85.7% of patients in the Preserfo and iStent groups, respectively (p = 0.045). Complete surgical success in criterion B at 12 months accounted to 61.4% of patients from Prserflo group and 32.7% patients in iStent group (p = 0.04). Surgical failure at 12 months was documented in 30.2% and 6.3% of patients, respectively (p = 0.003). There was a significant difference between groups in %IOP reduction after 12 months. Greater reduction was observed in Preserflo group, MD = - 8.41 CI95 [- 15.88; - 0.95], p = 0.028, (- 33.49% ± 21.59 vs - 25.07% ± 14.15 in iStent group). Both procedures effectively reduced IOP and postoperative use of antiglaucoma medications in glaucoma patients.

Glaucoma Surgery and Ocular Blood Flow in Colour Doppler Imaging: Is There a Link?

Glaucoma is a common cause of blindness worldwide. This disease is characterised by increased intraocular pressure (IOP) and the concomitant disruption of ocular haemodynamic. Several studies have demonstrated that trabeculectomy is associated with changes in extraocular blood flow. In this study, we reviewed the available evidence on the use of colour Doppler imaging to evaluate and manage patients with open-angle glaucoma. We present the detailed anatomy of ocular blood flow to provide a background for the research findings. We also discuss the physiological foundations of ocular blood flow and detailed flow characteristics of specific extraocular vessels. Finally, we reviewed published studies that analysed the effects of glaucoma surgery on the blood flow parameters of the eye.

Systematic Literature Review of Clinical, Economic, and Humanistic Outcomes Following Minimally Invasive Glaucoma Surgery or Selective Laser Trabeculoplasty for the Treatment of Open-Angle Glaucoma with or Without Cataract Extraction

Introduction

Selective laser trabeculoplasty (SLT) and minimally invasive glaucoma surgery (MIGS) are increasingly used options for mild-to-moderate open-angle glaucoma (OAG) care. While most MIGS devices are indicated for use in combination with cataract surgery only, with phacoemulsification playing a role in lowering IOP, newer technologies can also be used as standalone glaucoma surgery.

Methods

This systematic literature review (SLR) aimed to assess the clinical, economic, and humanistic outcomes of MIGS and SLT for the treatment of OAG and was conducted according to PRISMA guidelines. Studies that assessed MIGS or SLT in at least one treatment arm versus any other glaucoma treatment in adults with mild-to-moderate OAG were included. Clinical, humanistic (health-related quality of life [HRQoL] and patient burden), and economic data were extracted, and the methodological quality of included studies was evaluated.

Results

A total of 2720 articles were screened, and 81 publications were included. Fifty-eight reported clinical outcomes. The majority assessed iStent or iStent inject (n=41), followed by OMNI (n=9), gonioscopy-assisted transluminal trabeculotomy (GATT) or the Kahook Dual Blade (KDB) (n=7), Hydrus (n=6), SLT (n=5), Xen Gel Stent (n=2), PreserFlo (n=1), and iTrack (n=1). IOP reduction was observed across prospective studies, varying from -31% to -13.7% at month 6 and from -39% to -11.4% at year 1 versus baseline. Most adverse events were transient and non-serious. Limited humanistic and economic data were identified.

Conclusion

Given their established efficacy and safety, there is a rationale for wider use of MIGS in mild-to-moderate OAG. Of the MIGS devices, iStent and OMNI have the largest clinical evidence base supporting their sustained effectiveness.

Evaluation of the Effect of the First Generation iStent on Corneal Endothelial Cell Loss-A Match Case-Control Study

Glaucoma is the leading cause of irreversible blindness worldwide. The only proven factor in slowing the progression of glaucomatous neuropathy is lower intraocular pressure (IOP), which can be achieved with pharmacology, laser therapy, or surgery. However, these treatments are associated with various adverse effects, including corneal endothelial cell loss (CECL). In recent years, several novel surgeries for reducing the IOP, collectively referred to as minimally invasive glaucoma surgery (MIGS), have been developed, one of which is the iStent. However, the long-term effects of such surgeries remain unknown. We compared a group of patients with open-angle glaucoma and cataract who underwent phacoemulsification alone with a group of patients with similar demographic and clinical characteristics who underwent simultaneous phacoemulsification and iStent implantation. Overall, 26 eyes of 22 subjects who underwent a combined phacoemulsification-iStent procedure and 26 eyes of 24 subjects who underwent cataract surgery were included. Before surgery, endothelial cells accounted to 2228.65 ± 474.99 in iStent group and 2253.96 ± 404.76 in the control group (p = 0.836). After surgery, their number declined to 1389.77 ± 433.26 and 1475.31 ± 556.45, respectively (p = 0.509). There was no statistically significant difference in CECL between the two groups 18–24 months after surgery, despite increased manipulation in the anterior chamber and the presence of an implant in the trabecular meshwork in those with an iStent implant. Thus, iStent bypass implantation is a safe treatment in terms of CECL for mild-to-moderate open-angle glaucoma.

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.

Treatment Success Across Different Levels of Preoperative Disease Burden: Stratified Two-Year Outcomes from the Pivotal Trial of iStent inject ® Trabecular Micro-Bypass in Primary Open-Angle Glaucoma and Cataract

PURPOSE

To examine effectiveness outcomes stratified by preoperative disease burden in the pivotal trial of iStent inject ® with cataract surgery (INJ) vs cataract surgery alone (CS).

MATERIALS AND METHODS

Prospective, 3:1 randomized, single-masked, concurrently-controlled, multicenter trial enrolling 505 subjects with cataract and mild-to-moderate primary open-angle glaucoma who underwent iStent inject implantation with phacoemulsification or phacoemulsification alone, and were followed for 2 years including annual medication washouts. Post hoc stratification was completed for baseline mean diurnal intraocular pressure (BL DIOP; Low-DIOP <25mmHg, Mid-DIOP ≥25 to <30 mmHg, High-DIOP ≥30mmHg) and preoperative medication burden (Low-Med 1 medication, Mid-Med 2 medications, High-Med ≥3 medications).

RESULTS

The 24-month primary and secondary effectiveness endpoints were met, with significant treatment-over-control differences in percent of eyes achieving ≥20% unmedicated DIOP reduction and in unmedicated DIOP reduction, respectively. In subgroup analyses, the proportions of INJ eyes achieving the primary endpoint remained steady across all BL DIOP (75.4%, 77.1%, 74.4% in Low/Mid/High-DIOP strata, respectively) and preoperative medication levels (76.8%, 70.8%, 79.7% in Low/Mid/High-Med strata, respectively); meanwhile, the proportions of CS eyes diminished with higher BL DIOP (64.5%, 63.6%, 33.3%, respectively) and more medications (69.0%, 63.3%, 29.4%, respectively). Regarding secondary effectiveness, postoperative DIOP reduction increased with higher BL DIOP in INJ eyes (6.2mmHg, 7.8mmHg, 9.8mmHg, respectively) but plateaued in CS eyes (5.2mmHg, 5.8mmHg, 5.4mmHg, respectively). INJ eyes also had consistent DIOP reduction regardless of preoperative medication burden (6.8mmHg, 6.7mmHg, 7.8mmHg, respectively), while DIOP reduction diminished with more medications in CS eyes (6.1mmHg, 5.0mmHg, 3.3mmHg, respectively). Safety was favorable, comparable to phacoemulsification alone.

CONCLUSION

Significant IOP reductions occurred across all levels of BL DIOP and preoperative medication burden in iStent inject eyes. DIOP reductions increased with higher BL DIOP and remained stable across all levels of preoperative medication burden, suggesting the device's potential utility in more medically challenging cases.

XEN Glaucoma Implant for the Management of Operated Uncontrolled Glaucoma: Results and Complications during a Long-Term Follow-Up

This study aimed to analyze the surgical and refractive outcomes of XEN glaucoma implant (Allergan, an Abbvie company, Irvine, CA, USA), a minimally invasive surgical device for the treatment of operated uncontrolled glaucoma. Eyes that received XEN Gel Stent placement from December 2014 to October 2019 were retrospectively investigated. Intraocular pressure (IOP) change, best-corrected visual acuity (BCVA), change in glaucoma medications, frequency of slit lamp revision procedures, and frequency of secondary glaucoma surgeries were the primary outcomes. Seventy-two eyes of 72 subjects were included in the study: 32 (44%) men and 40 (56%) women. The follow-up period ranged from 1 to 50 months (median, 26.13 months). The mean IOP before surgery was 24.82 ± 8.03 mmHg and decreased to 17.45 ± 5.84 mmHg at the end of the study (mean difference [MD] = −7.48, 95% confidence interval [CI]: −10.04, −4.93; p < 0.001). The mean decrease from baseline was 23%. BCVA before surgery was 0.38 ± 0.30, and that at the end of the follow-up period improved to 0.47 ± 0.37, MD = 0.09, 95% CI: 0.04, 0.13; p < 0.001. Additional procedures (fluorouracil injection and bleb needling) were performed in 11/72 patients (15%). Further glaucoma surgery was necessary for 23.9% of the patients. XEN Gel Stent implantation is both safe and reasonably effective for lowering IOP in operated uncontrolled glaucoma patients.

Efficacy and safety of phacoemulsification plus goniosynechialysis and trabectome in patients with primary angle-closure glaucoma

We evaluated the efficacy and safety of combined phacoemulsification, intraocular lens implantation, goniosynechialysis (GSL), and trabectome in patients with primary angle-closure glaucoma (PACG). Twenty patients (22 eyes) of PACG treated with combined phacoemulsification, intraocular lens implantation, GSL, and trabectome between September 2017 and September 2020 were included in this case series study. The intraocular pressure (IOP), number of glaucoma medications, and best-corrected visual acuity (BCVA) were recorded at baseline, 1, 3, 6, and 12 months after surgery. Successful surgery was defined as IOP < 21 mmHg with or without IOP-lowering medications. IOP was decreased significantly from 22.07 ± 6.62 mmHg at baseline to 15.06 ± 3.39 mmHg at 12 months' follow-up (p = 0.001). The number of glaucoma medications was significantly reduced from 2.68 ± 1.17 preoperatively to 0.78 ± 0.73 at 12 months' follow-up (p < 0.01). The rate of successful surgery was 88.9% at 12 months. The reduction in IOP showed a positive correlation with baseline IOP (p < 0.001), and the reduction in number of glaucoma medications was positively correlated with baseline number of glaucoma medications (p < 0.001). There were no vision-threatening complications intraoperatively or postoperatively. Combined phacoemulsification, IOL implantation, GSL, and trabectome were effective and safe in PACG patients in this study. These combined surgical techniques may be useful in PACG patients, especially those with long term and extensive peripheral anterior synechiae.

Glaucoma Progression after Delivery in Patients with Open-Angle Glaucoma Who Discontinued Glaucoma Medication during Pregnancy

In this retrospective study, clinical characteristics and glaucoma progression of open-angle glaucoma (OAG) patients who discontinued intraocular pressure (IOP)-lowering medication during pregnancy were investigated. Glaucoma progression was determined using either serial visual field tests or optic disc/retinal nerve fiber layer (RNFL) photographs. Age, number of previous pregnancies, diagnosis, average IOP, IOP fluctuation, visual field mean deviation, pattern standard deviation, and RNFL thickness were examined, and their association with glaucoma progression was determined using linear regression analysis. Among 67 eyes (37 patients), 19 eyes (28.4%) exhibited glaucoma progression 13.95 ± 2.42 months after delivery. The progression group showed significantly higher mean IOP than the nonprogression group in the first, second, and third trimesters (p = 0.02, 0.001, and 0.04, respectively). The average IOP in the second^, and third trimesters and IOP fluctuation during the entire pregnancy were significantly associated with glaucoma progression according to a univariate analysis (p = 0.04, 0.031, and 0.026, respectively). In conclusion, IOP elevation during pregnancy is associated with glaucoma progression after delivery in patients who had discontinued medication during pregnancy. Therefore, close monitoring of glaucoma is necessary, particularly if patients discontinue medication during pregnancy, and appropriate intervention should be considered in case of increased IOP.

Fellow-Eye Comparison between Phaco-Microhook Ab-Interno Trabeculotomy and Phaco-iStent Trabecular Micro-Bypass Stent

The aim of this study is to compare the surgical efficacy and safety between microhook ab-interno trabeculotomy (µLOT) and iStent trabecular micro-bypass stent implantation when both were combined with cataract surgery in both eyes of patients. Sixty-four glaucomatous eyes (32 participants; mean age, 75.9 ± 7.6 years; 15 men, 17 women) were included retrospectively. Intraocular pressure (IOP), number of antiglaucoma medications, best-corrected visual acuity (BCVA), anterior chamber flare (ACF) and corneal endothelial cell density (CECD) were evaluated preoperatively, as well as 2, 3, 6, and 12 months postoperatively. Surgical complications and interventions were compared between the procedures. The preoperative IOP and medications with µLOT (18.8 ± 5.7 mmHg and 3.0 ± 1.2, respectively) were higher than with the iStent (15.5 ± 3.4 mmHg and 2.7 ± 1.2, respectively) (p = 0.0001 and p = 0.0437, respectively). At 12 months, the µLOT values (12.6 ± 2.3 mmHg and 2.3 ± 0.9, respectively) were identical to iStent (12.8 ± 2.5 mmHg and 2.3 ± 0.9, respectively) (p = 0.0934 and p = 0.3251, respectively). At 12 months, the IOP decreased more with µLOT (6.2 mmHg, 29.5%) than iStent (2.7 mmHg, 15.6%) (p = 0.0003). The decrease in medications was greater with µLOT (0.7) than iStent (0.4) (p = 0.0437). Survival rate of IOP control ≤15 mmHg and IOP reduction ≥20% was significantly higher after µLOT (40.6% at 12 months) than iStent (18.8%) (p = 0.0277). The frequency of layered hyphema was significantly greater with µLOT (8 eyes, 25%) than iStent (0 eyes, 0%) (p = 0.0048). The increase in the ACF at 2 weeks postoperatively was significantly greater with µLOT than iStent (p = 0.0156), while changes in the BCVA and CECD were identical between groups. The fellow-eye comparison showed that the IOP reduction was greater with µLOT than iStent when combined with cataract surgery.

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.

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

Purpose

The aim of this investigation was to evaluate the impact of iStent (the first-generation trabecular bypass) implantation with phacoemulsification on the intraocular pressure (IOP) and glaucoma medication in subjects with mild to moderate open-angle glaucoma (OAG) and cataract in a Polish Caucasian population.

Patients and Methods

This prospective case series covered 78 eyes of (57 Polish Caucasian patients) that had undergone iStent implantation in conjunction with cataract surgery. Patients were surveyed preoperatively and at postoperative day 1, week 1, and months 1, 3, 6, 12, and 24. Pre- and postoperative outcome measurements included visual acuity, IOP, and medication burden. Intraoperative and postoperative complications were noted for the safety profile. For effective treatment, an IOP reduction ≥20% was assumed, regardless of the use of IOP-lowering drops. Complete surgical success was defined as an IOP ≤ 15 mmHg, medications free, and a qualified surgical success as IOP ≤ 15 mmHg with or without medications.

Results

Post-operatively at two years, mean IOP reduced from 18.5 mmHg to 16.1 mmHg. The mean medication burden dropped from 1.8 to 0.4 at the end of follow-up. Preoperatively, 2 (2.6%) eyes were medication free, but by postoperative month 24, 53 (68%) eyes were medication-free (p < 0.05). Effective treatment was achieved in 50 cases (64%) at the end of follow-up period. Kaplan–Meier cumulative incidence of qualified success was 51.9% after 24 months, CI₉₅ [41.9%; 64.4%], while cumulative incidence of complete success after 2 years of observation was 35.1%, CI₉₅ [25.9%; 47.5%].

Conclusion

The iStent device combined with a cataract surgery served to decrease, significantly and positively, both IOP and medication use in the 24-months follow-up in patients with coexistent OAG and cataract in Polish patients.

Comparison of Safety and Efficacy Between Ab Interno and Ab Externo Approaches to XEN Gel Stent Placement

Purpose

To compare the safety and efficacy of two different techniques for implantation of the XEN Gel Stent, a minimally invasive surgical device for the treatment of refractory glaucoma.

Methods

A retrospective chart review of eyes that received ab interno or ab externo XEN Gel Stent placement from February 2017 to October 2019 was conducted. A single surgeon (NMR) performed all operations. Eyes that received the XEN implant concomitant with a glaucoma drainage device insertion or that were lost to 6-month follow-up were excluded. Intraocular pressure (IOP) change, change in glaucoma medications, frequency of slit lamp revision procedures, and frequency of secondary glaucoma surgeries were the primary outcomes compared between groups.

Results

Fifty eyes that underwent ab interno placement and 30 eyes that underwent ab externo placement were studied. The ab interno cohort demonstrated a mean IOP reduction of 8.4 ± 1.7 mmHg (28.6% decrease) by 12 months, compared to a mean reduction of 12.8 ± 3.0 mmHg (40.1% decrease) in the ab externo group (p = 0.208). Mean reduction in medication use was 1.81 ± 0.29 medications in the ab interno group and 1.86 ± 0.37 in the ab externo group (p = 0.913). By 12 months, 58% of ab interno eyes had required 5-fluorouracil injection compared to 36.7% of ab externos (p = 0.105). Bleb needling was applied to 42% and 26.7% of the eyes, respectively (p = 0.231). A second glaucoma surgery was necessary for 20% of the ab interno cohort and 10% of the ab externo cohort (p = 0.351).

Conclusion

There were no differences in outcomes between ab interno and ab externo placement of the XEN Gel Stent. Both approaches are safe and effective for lowering IOP.

Effects of Ripasudil on Open-Angle Glaucoma after Circumferential Suture Trabeculotomy Ab Interno

We evaluated the effects of ripasudil on the distal aqueous outflow tract in patients with open-angle glaucoma (OAG) who underwent a 360° suture trabeculotomy ab interno followed by ripasudil treatment beginning 1 month postoperatively. We compared 27 of these patients, by using propensity score analysis, with 27 patients in a matched control group who had no ripasudil treatment. We assessed the changes in the mean intraocular pressure (IOP) and the relationship between the IOP changes and background factors. All eyes had a complete 360° Schlemm’s canal incision and phacoemulsification. The mean IOP at 1 and 3 months after ripasudil administration were significantly reduced by −1.7 ± 1.9 mmHg (p < 0.0001) and −1.3 ± 2.3 mmHg (p = 0.0081) in the ripasudil group, respectively, but IOP in the control group was not significantly reduced. The IOP reduction was significantly associated with the IOP before ripasudil treatment (p < 0.001). In conclusion, the use of ripasudil for patients with OAG after circumferential incision of the Schlemm’s canal produced significant IOP reductions. Ripasudil may affect the distal outflow tract, thereby leading to the IOP reduction.

Turn Back Elevation of Once Reduced IOP After Trabeculotomy Ab Externo and Kahook Dual Blade Surgeries Combined with Cataract Surgery

Purpose

To evaluate the surgical outcome of internal trabeculectomy by Kahook dual blade (KDB) with that of external trabeculotomy, each combined with phaco-lensectomy and intraocular lens implantation (Phaco).

Patients and Methods

This is a retrospective comparative study. The primary and secondary outcome measures are postsurgical intraocular pressure and postsurgical hyphema. One eye each of 76 primary open angle glaucoma (POAG), pseudoexfoliation glaucoma (PEG) and ocular hypertension (OH) patients underwent external phaco-trabeculotomy, and that of 40 POAG, PEG and OH patients underwent phaco-KDB surgery.

Results

Reduction of the intraocular pressure (IOP) by phaco-KDB at one and two years was 28.4 and 27.8%, respectively, and was not significantly different from that by external phaco-trabeculotomy of 32.7% (P=0.256) and 31.5% (P=0.468), respectively. Three months postsurgical IOP after phaco-KDB and external phaco-trabeculotomy was 16.1 and 15.9 mmHg, respectively. There was a significant turn back elevation of once reduced IOP to 17.1 (P=0.0207) and 17.0 mmHg (P=0.0096) at 24 months, respectively. There were no differences in success probability to achieve IOP below 17 mmHg (P=0.120), 21 mmHg (P=0.719) and >20% IOP reduction (P=0.309) with medication(s) at two years between the phaco-KDB and external phaco-trabeculotomy cohorts. Younger age was a significant (P<0.001) risk factor for failure; however, presurgical IOP (P=0.466), the type of surgery (P=0.219) and presence of postsurgical IOP spike (P=0.737) were not significant risk factors by the Cox proportional hazard model. Hyphema and spike of the IOP in phaco-KDB and external phaco-trabeculotomy cohorts were 40% and 88% (P<0.001), and 53% and 41% (P=0.238), respectively.

Conclusion

The IOP reduction by the phaco-KDB was equivalent to that by external phaco-trabeculotomy up to two years. In both cohorts, once reduced postsurgical IOP tend to increase up to 24 months.