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.

Intraoperative challenges and outcomes of pediatric cataract surgery following glaucoma filtering surgery.

PURPOSE: To analyze the intraoperative challenges of cataract surgery in children, following glaucoma filtering surgery. METHODS: This was a retrospective study to analyze intra-op challenges and outcomes of pediatric cataract surgery in post-glaucoma filtration surgery eyes, between January 2007 and December 2019. RESULTS: We included 20 eyes of 16 children. The most common glaucoma surgery performed was trabeculectomy and trabeculotomy (14 eyes). The median age at the time of cataract surgery was 74.5 months. The most common cataract surgery performed was lens aspiration with posterior chamber intraocular lens implantation (LA + PCIOL) (9/20). The most common intraoperative challenge faced was difficulty in capsulorrhexis (ten eyes), followed by extension of primary posterior capsulotomy (six eyes). At the final follow up eight eyes had improvement in visual acuity, five eyes had stable visual acuity and five eyes had a drop in visual acuity. In 12/20 eyes IOL was implanted, nine eyes in-the-bag and three eyes had in ciliary sulcus. None of the IOLs in the bag had decentration of IOL. The median postoperative IOP (p = 0.12) and median number of postoperative AGM (p = 0.13) at 2 years remained stable compared to the preoperative values. The IOP remained well controlled in 4 eyes without anti-glaucoma medications and in 14 eyes with anti-glaucoma medications and none needed additional surgery for IOP control. Two eyes developed retinal detachment postoperatively. CONCLUSION: Cataract surgery in pediatric eyes with prior glaucoma surgeries, have challenges with capsulorrhexis and IOL stability. The visual outcomes were reasonably good so was the IOP control.

[Clinical characteristics and surgical management outcomes of glaucoma secondary to congenital ectropion uveae: a preliminary analysis of penetrating Schlemm's canaloplasty].

Objective: To investigate the clinical characteristics and treatment outcomes of glaucoma secondary to congenital ectropion uveae (CEU) using penetrating Schlemm's canaloplasty. Methods: This was a retrospective case series study. Medical records of patients diagnosed with glaucoma secondary to CEU and undergoing penetrating Schlemm's canaloplasty at the Eye Hospital of Wenzhou Medical University between August 2020 and December 2021 were collected. Clinical characteristics including the extent and location of iris ectropion, type of glaucoma, were analyzed. Follow-up visits were conducted at 1, 3, 6 months, and 1 year postoperatively. Visual acuity, intraocular pressure (IOP), anterior segment and fundus condition, filtering bleb morphology, use of IOP-lowering medications, ultrasound biomicroscopy results, and other indicators were analyzed to summarize surgical outcomes. Results: Six cases (6 eyes) of glaucoma secondary to CEU were included, all unilateral, with 3 left eyes and 3 right eyes; median age was 10.0 (5.3, 28.8) years; including 3 males and 3 females. Preoperative IOP was (31.7±10.0) mmHg (1 mmHg=0.133 kPa), and the preoperative number of IOP-lowering medications used was 2.0 (2.0, 3.2). The extent of iris ectropion in the 6 cases ranged from 270 ° to 360 °, with peripheral anterior synechiae corresponding to the location of iris ectropion, and angle closure with the degree of synechiae extending beyond Schwalbe's line. No surgical complications occurred in any of the 6 cases postoperatively. At 1 month postoperatively, the IOP was (16.4±3.2) mmHg, with a median of 0.0 (0.0, 1.5) medications used. At 3 months postoperatively, the IOP was (14.8±6.0) mmHg, with a median of 0.0 (0.0, 2.2) medications used. At 6 months postoperatively, the IOP was (18.1±6.1) mmHg, with a median of 0.0 (0.0, 0.5) medications used. Among them, 5 patients had a follow-up period of 1 year postoperatively, all achieving controlled IOP without the use of IOP-lowering medications, with an average IOP of (15.5±3.1) mmHg. No obvious filtering bleb formation was observed at the surgical site in all patients. Conclusions: Glaucoma secondary to CEU manifests primarily as closed-angle glaucoma, with a correspondence between the closure range of anterior iris adhesions in the angle and the extent of iris ectropion. Penetrating Schlemm's canaloplasty demonstrates favorable and stable efficacy for its treatment.

[Glaucoma Filtration Surgery - Bleb-forming Procedures]. / Filtrierende Glaukomchirurgie ­ Verfahren mit Bildung eines Filterkissens.

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

New suture probe canaloplasty combined with suprachoroidal collagen implantation.

PURPOSE: To present the modified surgery technique of new suture probe canaloplasty with a specially prepared monofilament 4.0 polypropylene suture combined with suprachoroidal drainage (ScD) and collagen sheet implantation for non-penetrating glaucoma surgery. METHODS: Prospective study with a twelve months follow-up. A standard 4/0 polypropylene suture (ProleneTM by Ethicon; thickness: approximately 250 m) is cut and shaped with an ophthalmic knife (MANI® Crescent Knife, Mani Inc 8-3 Kiyohara Industrial Park, Utsunomiya, Tochigi 321-3231, Japan) to create a blunt end without sharp or compressed edges. This improves suture probe canaloplasty by providing a more stable and smoother probing device. Schlemm's canal is prepared using the standard technique of canaloplasty with suprachoroidal drainage. Then, instead of using the canaloplasty microcatheter or the previously published 6/0 double-helix suture, Schlemm's canal is probed with the blunt ending of the 4/0 Prolene suture. After successful 360-degree probing, a doubled 10/0 polypropylene tension suture is threaded through the tip of the 4/0 suture. The 4/0 suture is then pulled back and the 10/0 tension sutures are tied at both ends to tension Schlemm's canal. A special collagen sheet (Ologen®) is placed in suprachoroidal space, and the scleral flap is firmly sewed. RESULTS: 115 eyes were included in this prospective study. In 113 cases the Schlemm's canal could completely be probed with the suture probe and canaloplasty with ScD and collagen sheet implantation succeeded. In two cases the intervention was transformed to 360-degree suture trabeculotomy due to an intraoperative cheese-wiring. Twelve months after successful new suture probe canaloplasty with ScD and Collagen Implantation the IOP had decreased by 37.1% (from 21.6 ± 6.0 mmHg with 3.3 different IOP lowering eye drops to 13.5 ± 3.5 mmHg with 1.0 eye drops). 16 Patients did not achieve sufficient IOP levels and underwent 360-degree suture trabeculotomy during the follow-up. One patient had to be treated with further glaucoma surgery to achieve a sufficient IOP level. Complications were hyphema, postoperative IOP elevation and transient hypotony. No serious or sight-threatening complications occurred. CONCLUSION: New suture probe canaloplasty with ScD and collagen sheet implantation yields the opportunity to conduct a cost-effective canaloplasty easier and less complicated than with the previously described method with the twisted 6/0 suture. The safety profile and IOP lowering effect is comparable. In cases where complete probing fails, there is still the opportunity to switch to suture trabeculotomy over the majorly probed part of Schlemm's canal. The pressure lowering effect of the deep sclerectomy with ScD and suprachoroidal collagen sheet implant seems to have an additional impact on the sufficient pressure lowering procedure.

Using a Novel, Subconjunctival, Sustained-Release Mitomycin C Formulation in a Rabbit Model of Filtration Surgery with Gel Stent Implantation.

Purpose: To investigate gel stent implantation with and without intraoperative sustained-release mitomycin C (MMC SR) in a rabbit model for gel stent implantation, and to examine aqueous humor outflow (AHO) postimplantation. Methods: Four groups of rabbits were included. Group 1 was untreated (control). Groups 2, 3, and 4 received the gel stent without MMC, with MMC solution (subconjunctival injection), and with MMC SR (subconjunctival injection), respectively. Intraocular pressure (IOP) and AHO were assessed via tonometry and indocyanine green-based angiography, respectively. The main efficacy measure was change in IOP from baseline. Results: Following gel stent implantation, Groups 2, 3, and 4 maintained ≥20% IOP reduction (response) for a median duration of 1 week, 6.5 weeks, and 30 weeks, respectively. Angiography showed normal aqueous humor drainage (Group 1) beginning at the perilimbal trabecular plexus and continuing posteriorly to episcleral outflow vessels. Following implantation, drainage occurred preferentially and directly into the subconjunctival bleb. Conclusions: Gel stent implantation with MMC SR was most effective in achieving sustained, long-term IOP reduction in the rabbit model, compared with implantation with or without MMC solution. Bleb presence and the postimplantation aqueous angiography results indicated redirection of the AHO to the subconjunctival vasculature and presumed lymphatics, suggesting efficient glaucoma filtration to lower IOP in this model. This rabbit model and aqueous angiography may help refine understanding of the mechanism of action of minimally invasive glaucoma surgeries and ultimately translate to improved surgical devices and procedures for patients with glaucoma.

Bleb vessel density as a predictive factor for surgical revisions after Preserflo Microshunt implantation.

PURPOSE: Bleb failure is a common complication after glaucoma filtration surgery. Different bleb classification schemes incorporating filtration bleb vascularization have been proposed, but the reported correlation with intraocular pressure (IOP) has been variable, possibly because of subjective vascularization grading. The purpose of the present study was to evaluate bleb vascularization after Preserflo Microshunt (PM) implantation using anterior segment OCT-angiography (AS-OCTA) as a biomarker for bleb failure. METHODS: Twenty-three eyes of twenty-three patients underwent PM implantation. Up to 12 months after surgery PM scleral passage-centred AS-OCTA measurements (PLEX Elite 9000) for bleb-vessel density (BVD) determination were performed and IOP as well as necessity for surgical revisions (needling and open revision) were documented. After multi-step image analysis (region of interest definition, artefact removal, binarization, BVD calculation), the predictive value of early postoperative BVD for surgical revisions was assessed using logistic regression modelling. RESULTS: Baseline IOP (23.57 ± 7.75 mmHg) decreased significantly to 8.30 ± 2.12, 9.17 ± 2.33 and 11.70 ± 4.40 mmHg after 1, 2 and 4 week(s), and 13.48 ± 5.83, 11.87 ± 4.49, 12.30 ± 6.65, 11.87 ± 3.11 and 13.05 ± 4.12 mmHg after 2, 3, 6, 9 and 12 month(s), respectively (p < 0.001). Nine patients (39%) needed surgical revisions after a median time of 2 months. Bleb vessel densities at 2 and 4 weeks were significantly associated with future surgical revisions upon logistic regression analysis (2 W/4 W likelihood-ratio test p-value: 0.0244/0.0098; 2 W/4 W area under the receiver operating characteristics curve: 0.796/0.909). CONCLUSION: Filtration bleb vessel density can be determined using AS-OCTA in the early postoperative period and is predictive for bleb failure after PM implantation.

Successful resolution of serous macular detachment following glaucoma-filtering surgery alone for acquired optic disc pit maculopathy.

PURPOSE: To describe a case of acquired glaucomatous optic disc pit-related maculopathy successfully treated with glaucoma filtering surgery alone. CASE DESCRIPTION: A 67-year-old male was diagnosed with advanced primary open angle glaucoma in both eyes, with a cup: disc ratio of 0.85 in the right eye and 0.95 in the left eye. Visual acuity at presentation was 20/60, and intraocular pressure was 14 mm Hg in the left eye. The fundus of the left eye revealed a serous macular retinal detachment due to an acquired optic disc pit. RESULTS: The left eye of the patient underwent combined cataract and glaucoma filtering surgery. The serous macular detachment resolved completely 15 months after surgery, with a documented visual acuity of 20/40 and intraocular pressure of 10 mm Hg without the use of additional antiglaucoma medications. There was no recurrence of serous macular detachment even after the two-year follow-up visit. CONCLUSION: This case demonstrates that controlling intraocular pressure alone resulted in complete resolution of serous macular detachment in acquired optic disc pit maculopathy without the need for pars plana vitrectomy.

Clinical Characteristics and Surgical Outcomes of Turkish Patients With Pediatric Glaucoma Who Underwent Glaucoma Surgery in a University Hospital.

PURPOSE: To describe the clinical characteristics and outcomes of a pediatric cohort surgically treated for primary or secondary pediatric glaucoma (PPG/SPG). METHODS: A retrospective chart review was conducted of all patients with pediatric glaucoma who had surgery between 2013 and 2021. Relevant demographic and clinical data were cumulated and analyzed. RESULTS: Forty-two eyes of 29 patients (18 girls and 11 boys) were included: 22 (52.4%) primary congenital glaucoma (PCG), 7 (16.7%) juvenile open-angle glaucoma, and 13 (30.9%) SPG. Mean ages at presentation were 2.57 ± 2.87, 131.96 ± 27.71, and 62.09 ± 65.12 months, respectively. In this study, eyes with PCG presented the earliest, with the highest intraocular pressure (IOP) and thickest central corneal thickness (CCT). The mean number of glaucoma surgeries was 1.48 ± 0.71, with 38.1% of the eyes needing two or more glaucoma surgeries; trabeculectomy was the most frequent glaucoma surgery in this cohort. After surgical intervention, the overall mean IOP dropped from 32.25 ± 12.97 to 18.10 ± 9.23 mm Hg (P < .001). Moreover, the percentage using antiglaucoma medications decreased from 100% to 35.7% at the final visit, as did the number of medications prescribed per eye (2.69 ± 0.92 vs 1.05 ± 1.46, P ≤ .001). Mean best corrected visual acuity (BCVA), in patients who could have their BCVA measured, improved from 0.61 ± 0.61 to 0.53 ± 0.51 logMAR at final follow-up. CONCLUSIONS: Surgical intervention was shown to provide a well-controlled IOP, decrease dependance on glaucoma medications, and improve BCVA in both PPG and SPG. Multiple surgical interventions may be necessary in the treatment of some pediatric patients with glaucoma. Prognostically, thicker CCT was significantly associated with worse IOP control, more glaucoma surgeries, and more antiglaucoma medications at the final visit. Initial BCVA correlated significantly with BCVA at the final visit. [J Pediatr Ophthalmol Strabismus. 2024;61(3):188-197.].

Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges.

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

[Review by the French Glaucoma Society on the roles of new surgical techniques in glaucoma]. / Mise au point de la Société française du glaucome sur la place des nouvelles techniques chirurgicales dans le glaucome.

The surgical management of glaucoma has been enriched in recent years by the arrival of new surgical techniques as a group known as MIGS (minimally invasive glaucoma surgery). The objective of these new techniques is to reduce intraocular pressure (IOP) while limiting the risk of complications of conventional filtering surgery and allowing faster visual recovery. MIGS can be classified into three main categories depending on the route used to promote the outflow of aqueous humor: the trabecular route, the suprachoroidal route and the subconjunctival route. MIGS using the subconjunctival route are also called minimally invasive bleb surgery (MIBS). These new techniques do not replace conventional filtering surgery, which remains the gold standard technique, but now offer new alternatives for the surgical management of glaucoma patients in combination with cataract surgery or as stand-alone procedures.

Clinical outcomes of penetrating canaloplasty in patients with traumatic angle recession glaucoma: a prospective interventional case series.

BACKGROUND/AIM: To evaluate the clinical outcomes of penetrating canaloplasty in traumatic angle recession glaucoma at 1 year. METHODS: Patients with angle recession glaucoma underwent penetrating canaloplasty, a new Schlemm's canal-based internal drainage procedure, which creates a direct canal for flow of aqueous humour from the anterior chamber to the ostia of Schlemm's canal via a window created at the corneal scleral bed without use of antimetabolites. Postoperative intraocular pressure (IOP), number of glaucoma medications, and procedure-related complications were evaluated. Success was defined as an IOP ≤21 mm Hg without (complete) or with (qualified) use of glaucoma medication. RESULTS: Forty eyes in 40 patients with angle recession glaucoma underwent successful circumferential catheterisation. The mean patient age was 42±13 years. In patients with penetrating canaloplasty that was deemed to be completely successful, the mean IOP decreased from a preoperative value of 37.8±12.3 mm Hg on 3.3±1.2 anti-glaucoma medications to 18.5±6.4 mm Hg on 1.2±1.4 medications, 14.9±4.6 mm Hg on 0.1±0.5 medications, 15.7±5.4 mm Hg on 0.1±0.4 medications and 14.8±3.6 mm Hg on 0.1±0.5 medications at 1, 3, 6 and 12 months postoperatively (p<0.05). Complete success was achieved in 35/40 eyes (87.5%) at 6 months and in 34/38 (89.5%) at 12 months. Hyphema (18/40, 45.0%) and transient IOP elevation (≥30 mm Hg, 9/40, 22.5%) were the most common postoperative complications. CONCLUSION: Penetrating canaloplasty significantly reduces IOP and has a high success rate in angle recession glaucoma. TRIAL REGISTRATION NUMBER: ChiCTR1900020511.

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.

Achieving Inner Aqueous Drain in Glaucoma Secondary to Iridocorneal Endothelial Syndrome: One Year Results of Penetrating Canaloplasty.

PURPOSES: To report the efficacy of a bleb-independent penetrating canaloplasty in the management of glaucoma secondary to iridocorneal endothelial syndrome (GS-ICE). DESIGN: Prospective, non-comparative clinical study. METHODS: Penetrating canaloplasty was performed on 35 eyes from 35 patients with GS-ICE and medically uncontrolled intraocular pressure (IOP) between January 2018 and April 2020. Patients were followed up at 1 week, months 1, 3, 6, 12 postoperatively, and semi-annually thereafter. The IOP, anti-glaucoma medication, and surgery-related complications were recorded. Surgical success was defined as IOP ≥ 5 mmHg and ≤ 21 mmHg without (complete success) or with/without (qualified success) IOP-lowering medication. RESULTS: A total of 29 eyes (82.9%) had 360° catheterization and successfully received penetrating canaloplasty. Of these eyes, 24 (82.8%) achieved qualified success and 22 (75.9%) achieved qualified success at 12 months after surgery. The mean IOP decreased from 39.5 ± 11.8 mmHg on 2.9 ± 1.0 medications before surgery to 16.6 ± 5.3 mmHg (P < .001) on 0.2 ± 0.6 medications (P < .001) at 12 months postoperatively, respectively. Hyphema (37.9%), transient hypotony (34.5%), and transient postoperative IOP elevation (≥ 30 mmHg, 17.9%) were the most commonly observed early complications at the 1 week and 1 month visits. From 1 month and beyond, all treated eyes showed no obvious bleb at the operation quadrant. CONCLUSIONS: Penetrating canaloplasty rescued the inner aqueous outflow in ICE eyes and demonstrated acceptable success in IOP control with few complications, providing a new option for the management of GS-ICE.

Canaloplasty - Efficacy and Safety in an 18-Month Follow Up Period, and Analysis of Outcomes in Primary Open Angle Glaucoma Pigmentary Glaucoma and Pseudoexfoliative Glaucoma.

PURPOSE: Open-angle glaucoma (OAG), accounting for 90% of all glaucoma cases, is a progressive optic nerve neuropathy. It may lead to irreversible loss of visual field and complete blindness. When conservative treatment becomes insufficient to stop OAG progression, a surgical intervention is considered. Currently, canaloplasty procedure is being introduced instead of conventional trabeculectomy for invasive OAG treatment. The aim of the study is to asses safety and efficacy of canaloplasty. METHODS: This prospective study included 67 eyes that received 360° canaloplasty with placement of a tensioning suture. Primary OAG (n = 35), secondary OAG in pseudoexfoliative syndrome (n = 13), and pigmentary glaucoma (n = 19) patients were included. Control check-ups were conducted pre-operatively and in a 18-month follow-up time. Study endpoints involved reduction in IOP values and in the number of glaucoma medications after the intervention. RESULTS: The intervention led to a significant 38% reduction in IOP value from the preoperative baseline to 18 months after the intervention. The number of medications decreased significantly by 89%. At 18 months postoperative, 79% eyes did not require any glaucoma medications. The incidence of complications after canaloplasty was low, and none of the adverse effects were vision threatening. A surgically-induced astigmatism was the most frequent complication. Pigmentary glaucoma patients were the most beneficial subgroup, with 50% reduction in IOP, the highest success rate, and 98% reduction in the number of medications used. CONCLUSION: This study proved that canaloplasty is an efficient and safe procedure in OAG eyes.

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.

A modified model of glaucoma filtering surgery in Sprague-Dawley rats.

Animal models are useful in glaucoma research to study tissue response to wound healing. Smaller animals such as rats offer additional advantages in terms of availability of detection antibodies and microarrays with cheaper maintenance costs. In this study, we describe a glaucoma filtering surgery (GFS) model in adult Sprague-Dawley rats by performing a sclerostomy using a 26-G needle and additionally placing a silicone tube (27 G) connecting the anterior chamber to the subconjunctival space to maintain a patent fistula for the flow of aqueous humor, thus providing a more definitive bleb. This technique will be useful in identifying and modifying newer targets in the wound healing process in order to improve surgical outcomes following GFS.

Anterior-segment optical coherence tomography of filtering blebs in the early postoperative period of ab externo SIBS microshunt implantation with mitomycin C: Morphological analysis and correlation with intraocular pressure reduction.

PURPOSE: To analyse the morphological evolution of filtering blebs with anterior-segment OCT (AS-OCT) and its correlation with intraocular pressure after ab externo SIBS microshunt implantation with mitomycin C (MMC) during a 3-month follow-up period. METHODS: Twenty-eight filtering blebs of 28 patients with open-angle glaucoma were measured horizontally and vertically in the sub-Tenon space with AS-OCT after ab externo SIBS microshunt implantation with MMC. The intraocular pressure (IOP) was monitored simultaneously at each visit. Maturation of and morphological changes in the blebs and correlations with the IOP were recorded. RESULTS: The average median preoperative IOP of 20.7 (range, 12-30) mmHg decreased to 8.5 (range, 4-17), 8.9 (range, 5-17), 10.4 (range, 8-16) and 10.9 (range, 9-15) mmHg at 24 hr, 1 week, 1 month and 3 months, respectively (p < 0.001). A multiform morphology on AS-OCT prevailed at all time points, with a 3.5% rate of a uniform bleb morphology at the first week. The horizontal and vertical diameters of the blebs increased from baseline to the third month. The horizontal expansion (406 ± 127 µm on day 7, p = 0.04, 712 ± 211 µm on day 30, p = 0.02 and 952 ± 218 µm on day 90, p < 0.001) was greater than the vertical expansion (16 ± 18 µm, p = 0.3 on day 1, 63 ± 27 µm, p = 0.02 on day 30 and 137 ± 34 µm, p < 0.001 on day 90) without correlation with the IOP (r = -0.3, p = 0.2). CONCLUSION: Anterior-segment OCT (AS-OCT) of the filtering blebs formed after ab externo SIBS microshunt implantation showed progressive horizontal and vertical expansion of the blebs in the sub-Tenon space, with a significant peak at the first month not significantly correlated with the decrease in the IOP.

Clinical outcomes of viscocanalostomy and phacoviscocanalostomy in primary open angle glaucoma: Two years follow-up.

PURPOSE: To compare the outcomes of phacoviscocanalostomy and viscocanalostomy in patients with primary open angle glaucoma. METHODS: This non randomized, prospective comparative study included 168 eyes of 168 patients with primary open angle glaucoma (POAG). Phacoviscocanalostomy was performed in 94 eyes with POAG and cataract and viscocanalostomy was performed in 74 eyes with POAG. Preoperative and postoperative intraocular pressures (IOP), number of antiglaucoma medication, intraoperative and postoperative complications were recorded throughout the follow-up period. RESULTS: The mean follow-up after surgery was 20.13 ± 7.9 months. Mean IOP decreased significantly 1 month after surgery in both groups (p < 0.001) and remained significantly lower from its preoperative value at all follow-up visits. The postoperative mean IOP at the last follow up in phacoviscocanalostomy and viscocanalostomy was 14.98 ± 4.8 mmHg and 16.84 ± 5.0 mmHg, respectively (p = 0.001). Complete success rate in phacoviscocanalostomy and viscocanalostomy groups was 83.1% and 56.8%, respectively (p = 0.008). Qualified success rate was achieved in 89.4% eyes in the phacoviscocanalostomy group and 83.8% of viscocanalostomy group (p = 0.534). The Best corrected visual acuity (BCVA) in phacoviscocanalostomy group improved significantly post-operatively (p = 0.001). Postoperative antiglaucoma medication in both groups were significantly less than the preoperative values (p = 0.001). CONCLUSIONS: Both Phacoviscocanalostomy and viscocanalostmy are effective procedures in the control of IOP in patients with POAG with and without cataract. Higher complete success rates and BCVA were achieved in phacoviscocanalostomy. Therefore, phacoviscocanalostomy and viscocanalostomy are recommended in eyes with medically uncontrolled primary open-angle glaucoma with and without coexisting cataract.

Statin use and the reoperation rates in glaucoma filtration surgery - population-based cohort study.

PURPOSE: To examine the association of systemic statin therapy and reoperation rate after glaucoma filtration surgery (GFS). METHODS: This is a population-based, historic cohort study of 2705 eyes undergoing GFS in Finland between July 2009 and December 2016. GFSs were identified from national administrative healthcare registers. Baseline sociodemographic and health characteristics were documented. Reoperation rates of GFS subgroups were analysed, with statin users compared to non-users. The outcomes were modelled using a Poisson regression model adjusted for age, sex, education, statin use, chronic comorbidities, and cataract surgery with incident rate ratios (IRR) as the main outcome measure. RESULTS: The cohort contained 2263 subjects with open-angle glaucoma (OAG), 823 men and 1440 women. Surgery was performed on 2705 eyes. First documented procedures: deep sclerectomy (DS) (n = 1601), trabeculectomy (TRE) (799) and glaucoma drainage device (GDD) implantation (305) respectively. In total, 438 secondary operations were performed during the 7.5-year (median 2.25 years) follow-up period. The reoperation rates were 19% after DS, 12% after TRE, and 13% after GDD. Of the surgical procedures, 32% were performed on eyes of patients receiving statin therapy. Statin users showed no difference in reoperation rates (IRR 1.06, CI 0.82-1.37). In subgroups, no difference was observed in the reoperation rates adjusted with statin use after filtration surgery (DS, TRE) (IRR 1.06, CI 0.8-1.40) or GDD implantation (0.57, CI 0.20-1.63). CONCLUSION: Systemic statin therapy among surgically treated OAG patients had no impact on secondary surgery rates following DS, TRE or GDD implantation.