Effectiveness and Safety of Xen Gel Stent in Glaucoma Surgery: A Systematic Review of the Literature.

Although topical medical therapy and selective-laser-trabeculoplasty represent the treatments of choice to reduce intraocular pressure, many patients do not achieve adequate glaucoma control; therefore, they require further options and eventually surgery. Trabeculectomy is still considered the gold standard, but the surgical management of glaucoma has undergone continuous advances in recent years, XEN-gel-stent has been introduced as a safer and less traumatic means of lowering intraocular pressure (IOP) in patients with open-angle glaucoma (OAG). This study aimed to review the effectiveness and safety of clinical data on XEN-stent in OAG patients with a Synthesis-Without-Meta-analysis (SWiM) methodology. A total of 339 studies were identified following a literature search adhering to PRISMA guidelines and, after evaluation, 96 studies are discussed. XEN63 and XEN45 device data were collected both short and long term. In addition, this document has evaluated different aspects related to the XEN implant, including: its role compared to trabeculectomy; the impact of mitomycin-C dose on clinical outcomes; postoperative management of the device; and the identification of potential factors that might predict its clinical outcomes. Finally, current challenges and future perspectives of XEN stent, such as its use in fragile or high myopia patients, were discussed.

Efficacy and Safety of PreserFlo® MicroShunt After a Failed Trabeculectomy in Eyes with Primary Open-Angle Glaucoma: A Retrospective Study.

INTRODUCTION: To evaluate the efficacy and safety of PreserFlo® MicroShunt in primary open angle glaucoma (POAG) eyes after a single failed trabeculectomy. METHODS: Retrospective review of POAG eyes with a failed trabeculectomy that underwent PreserFlo® MicroShunt implantation from March 2019 to November 2019, in two Italian glaucoma centers. Pre- and postoperative data were collected and compared. RESULTS: A total of 31 surgeries in 31 patients were reviewed. Mean preoperative IOP and mean preoperative number of medications were 24.12 ± 3.14 mmHg and 3.29 ± 0.64, respectively, and decreased to 12.56 ± 2.64 mmHg and 0.46 ± 0.77 at the 12-month postoperative follow-up visit (p < 0.01). The most frequent adverse events were transient hypotony (6 eyes, 19.3%) and choroidal effusion (3 eyes, 9.6%). In all cases spontaneous resolution was observed, with no intervention. CONCLUSION: In POAG eyes with a single failed trabeculectomy, the PreserFlo® MicroShunt was safe and effective in reducing the IOP after a 12-month follow-up. The PreserFlo® MicroShunt may represent a viable choice as a second surgery.

Surgical alternative to trabeculectomy.

Non-penetrating glaucoma surgery, represented by deep sclerectomy and viscocanalostomy, is an effective method to lower intraocular pressure (IOP) in glaucomatous patients. Both procedures reduce IOP by allowing aqueous humor drainage without opening the anterior chamber. Deep sclerectomy, similar to trabeculectomy, provides aqueous external filtration in the subconjunctival space. This technique, with the adjunctive use of implants, antimetabolites, and goniopuncture, may provide final IOP comparable to those obtained with trabeculectomy, but with less complications. Viscocanalostomy is less dependent on external filtration since it increases trabecular aqueous outflow facility by micro-disrupting Schlemm's canal walls and juxtacanalicular trabecular meshwork. This technique is very safe, but it provides higher final IOPs compared to trabeculectomy. Non-penetrating surgery should be therefore considered a surgical alternative to trabeculectomy in specific clinical cases.

Criteria for choosing clinically effective glaucoma treatment: A discussion panel consensus.

UNLABELLED: Abstract. BACKGROUND: In the clinical management of patients at risk for or diagnosed with primary open-angle glaucoma (POAG), the aim of medical treatment is to reduce intraocular pressure (IOP) and then maintain it over time at a level that preserves both the structure and function of the optic nerve. OBJECTIVE: The objective of this report was to establish a consensus on the criteria that should be used to determine the characteristics of IOP-lowering medication. METHODS: Discussion was held among a panel of 12 physicians considered to be experts in glaucoma to develop a consensus on the criteria used by them to determine the characteristics of the IOP-lowering medication chosen for initial monotherapy and adjunctive treatment of ocular hypertension (OHT) or POAG. Consensus development combined available evidence and the impressions of these physicians regarding the clinical effectiveness of IOP-lowering medication for OHT and POAG. Once the panel identified the criteria, the order of priority and the relative importance of these criteria were then established in the setting of 3 risk categories (low, medium, and high) for a patient to experience significant visual disability from glaucoma over their expected life span. RESULTS: The panel identified 5 criteria to determine the characteristics of IOP-lowering medication for OHT and POAG: IOP-lowering effect, systemic adverse events (AEs), ocular tolerability, compliance/administration, and cost of treatment. IOP-lowering effect was consistently ranked as the highest priority and cost as the lowest. The priority of compliance/administration did not vary by clinical situation. Systemic AEs and ocular tolerability were ranked as higher priorities in initial monotherapy than in adjunctive treatment and ranked lower as the risk for visual disability increased. The priority given to the criteria used to determine clinical effectiveness varied both with the risk for functional vision loss from glaucoma and whether initial monotherapy or adjunctive treatment was being considered. CONCLUSION: Glaucoma treatment should be assessed with regard to the need not only to lower IOP but also to minimize systemic and ocular AEs, promote patient compliance, and minimize cost. The order of priority and relative importance given to these treatment criteria will vary as part of individualizing patient care.

Failure of medical therapy despite normal intraocular pressure.

The disease glaucoma is now defined by characteristic optic disc and visual field change, without specific reference to the intraocular pressure (IOP). Success of treatment is no longer judged by the mere attainment of IOP less than 21 mmHg. Controversy remains, however, in deciding appropriate management where optic disc and/or visual field damage continues to progress despite a 'normal' IOP having been achieved with medical treatment. A panel of international glaucoma experts has provided management recommendations in four clinical scenarios--open-angle glaucoma, open-angle glaucoma in a myopic contact lens wearer, uveitic glaucoma and open-angle glaucoma in combination with visually significant cataract--where optic nerve and visual field progression has continued despite an IOP less than 21 mmHg on full medical treatment. Surgical intervention with mitomycin trabeculectomy is the most favoured further therapy.

An evaluation of the rate of nonresponders to latanoprost therapy.

PURPOSE: To determine the proportion of patients with primary open-angle glaucoma (POAG) or ocular hypertension (OH) who do not respond to latanoprost therapy. METHODS: Three hundred forty consecutive patients with a new diagnosis of POAG or OH, or previously treated only with a beta-blocker and after an appropriate washout period, were treated with latanoprost for 1 month and then divided into three groups on the basis of the reduction in intraocular pressure (IOP): nonresponders (<15%), responders (> or =15% but <30%), and high-responders (> or =30%). To give a wide picture of the drug effect, eight different cut-off points were used to present data on distribution of mean IOP reductions. Only the nonresponders entered a randomized cross-over study investigating the efficacy of timolol, brimonidine, and pilocarpine. RESULTS: IOP at baseline and after 1 month's latanoprost therapy was respectively 24.1+/-1.4 and 16.9+/-2.4 mm Hg, with a mean reduction in IOP of 29.9+/-4.2%. Nonresponders accounted for 4.1% of the patients and high-responders for 41.2%. The nonresponders showed a statistically significant reduction in IOP after brimonidine treatment (P=0.05), whereas the reduction after timolol and pilocarpine treatment was clinically relevant but not statistically significant. CONCLUSIONS: This multicenter prospective study found only 14 of 340 nonresponders to latanoprost. In the cross-over trial on nonresponders, IOP reduction reached statistical significance only after brimonidine, but their small number reduced its statistical power.

Viscocanalostomy in rhesus monkeys.

OBJECTIVE: To examine structural changes and aqueous humor outflow after viscocanalostomy in live normal monkey eyes. METHODS: Viscocanalostomy surgery was performed in 1 eye of each of 4 rhesus monkeys. Outflow facility was determined before and after surgery. All eyes were fixed and examined by light and/or electron microscopy 36 or 63 days postoperatively. RESULTS: Schlemm canal was replaced by scar tissue at the surgical site. The juxtacanalicular zone contained homogeneous material, probably high-molecular-weight 1.4% sodium hyaluronate. The sclera external to Schlemm canal was overhydrated, and remains of a scleral lake were present in 1 animal. Multiple defects were present in the endothelial lining of Schlemm canal inner and outer wall. Fine fibrillar material and sheath-derived plaque material partly bridged the defects. Along the inner wall, aggregations of thrombocytes covered some defects in the endothelial lining of the canal. At 90 degrees to 180 degrees from the surgical site, small and fewer breaks in the inner wall were seen. Postsurgery outflow facility (n = 2) was approximately 30% higher in the treated eye than in the contralateral control, corrected bilaterally for presurgery baseline. CONCLUSIONS: The most likely explanations for the increase in outflow facility in monkeys after viscocanalostomy are focal disruptions of the inner wall endothelium of Schlemm canal and disorganization of the juxtacanalicular zone, resulting in direct communication of juxtacanalicular zone extracellular spaces with the lumen of Schlemm canal. The continuous presence of sodium hyaluronate might prevent repair of these defects by interfering with thrombocyte function. CLINICAL RELEVANCE: In nonhuman primates, viscocanalostomy appears to decrease outflow resistance through persisting focal disruption of the inner wall endothelium and opening of the juxtacanalicular or cribriform region of the trabecular meshwork, the tissue most affected by pathologic changes in primary open-angle glaucoma in humans.

Viscocanalostomy in patients with glaucoma secondary to uveitis: preliminary report.

PURPOSE: To assess the efficacy of viscocanalostomy in eyes with uncontrolled glaucoma secondary to uveitis. SETTING: Immunology and Uveitis Service, Department of Ophthalmology and Visual Sciences, University Hospital San Raffaele, Milan, Italy. METHODS: All consecutive patients with glaucoma secondary to uveitis and inadequate intraocular pressure (IOP) control (IOP >21 mm Hg) under maximum-tolerated medical therapy had viscocanalostomy. Patients with active uveitis at the time of surgery, peripheral anterior synechias in the upper quadrant, previous ocular surgery, or sight in only 1 eye were excluded. Eleven eyes of 11 patients with a mean age of 52.2 years +/- 19.9 (SD) were operated on. The etiology of the uveitis was recorded. The ocular variables were IOP, best corrected visual acuity, number of antiglaucoma medications, and complications. Success was defined as an IOP between 6 mm Hg and 21 mm Hg (inclusive) without medication (complete success), or with 1 or more antiglaucoma medications and/or goniopuncture (qualified success). The mean follow-up was 45.9 +/- 11.6 months (range 23 to 56 months). RESULTS: Viscocanalostomy significantly reduced IOP from a mean baseline value of 35.1 +/- 7.0 mm Hg (range 23 to 48 mm Hg) to a mean final value of 18.1 +/- 4.9 mm Hg (range 12 to 30 mm Hg) (P<.0001). Complete success was achieved in 6 eyes (54.5%) and qualified success, in 10 eyes (90.9%). The mean number of preoperative and final antiglaucoma medications was 3.4 +/- 0.8 (range 2 to 4) and 0.7 +/- 1.2 (range 0 to 3), respectively (P =.0004). Complications were minor and included transient hyphema and postoperative IOP spike. CONCLUSION: This preliminary study suggests that viscocanalostomy is a safe, effective surgical alternative for treating glaucoma in patients with uveitis.

Gold standard medical therapy for glaucoma: defining the criteria identifying measures for an evidence-based analysis.

BACKGROUND: Over the past decade, several new medical therapies have become available for the treatment of primary open-angle glaucoma (POAG). A systematic evidence-based approach for identifying an optimal therapeutic agent is lacking. OBJECTIVES: The aims of this review were to critically evaluate published treatment recommendations for POAG and, based on a systematic review of the literature, to develop criteria that would define a "gold standard" medical therapy that reflects new treatment advances and established therapeutic goals. METHODS: A MEDLINE search spanning the years 1966 to 2002 and using the search terms gold standard, drug of choice, agent of choice, benchmark, ophthalmology, eye, and glaucoma was conducted and the results reviewed by a panel of 15 experts in the field of glaucoma. Published treatment recommendations for POAG were discussed. Criteria, anchored to medical evidence, for distinguishing a standard of medical therapy for POAG were defined. RESULTS: The terms connoting a gold standard therapy were found in only 258 of approximately 368,000 ophthalmology-related citations and 53 of almost 23,000 glaucoma citations, validating the need to define therapeutic standards. The lack of recommendations for the use of new classes of ocular hypotensive agents was acknowledged. Criteria identified to evaluate intraocular pressure (IOP)-lowering agents as gold standards included the following: efficacy in reducing IOP consistently over a 24-hour period to a level that will preserve the visual field and protect the optic nerve without inducing tachyphylaxis and tolerance, paucity of local and systemic adverse effects, promotion of patient compliance, and applicability in diverse patient populations. CONCLUSIONS: These criteria should be employed as measures for evidence-based analyses to evaluate available and future IOP-lowering medical therapies for POAG. The conceptual framework presented may be applicable to other therapeutic areas.

Viscocanalostomy versus trabeculectomy in white adults affected by open-angle glaucoma: a 2-year randomized, controlled trial.

PURPOSE: To compare the effectiveness and safety of viscocanalostomy and trabeculectomy in adults with uncontrolled open-angle glaucoma. DESIGN: Single-masked, parallel-group, prospective, randomized 24-month trial, with 90% power to detect a clinically important difference between groups. PARTICIPANTS: Fifty consecutive patients (50 eyes) with primary open-angle or pseudoexfoliative glaucoma. INTERVENTION: Eyes were assigned randomly to either viscocanalostomy (group 1) or trabeculectomy (group 2) with no intraoperative antifibrotics in the study eye. In group 1, no further intervention was allowed, whereas trabeculectomy eyes could receive subconjunctival 5-fluorouracil (5-FU) injections or laser suture lysis after surgery. MAIN OUTCOME MEASURES: Success rate based on intraocular pressure (IOP), visual acuity, discomfort, and other complications. RESULTS: At the end of the 24-month follow-up, IOP of 21 mmHg or less and more than 6 mmHg was achieved in 76% in group 1 (n = 19) and in 80% in group 2 (n = 20; log-rank P = 0.60); an IOP between 6 and 16 mmHg was obtained in 56% in group 1 (n = 14) and in 72% in group 2 (n = 18; log-rank P = 0.17; Kaplan-Meier cumulative probability of success). Complications of viscocanalostomy included one intraoperative conversion into trabeculectomy; microruptures in Descemet's membrane in five eyes; three cases of iris incarceration in the Decemet's window, two of which caused early failure of the procedure requiring reoperation; and a 1-mm to 2-mm transient self-resolving hyphema in three cases. Complications of trabeculectomy included one case of postoperative bleb bleeding with early transient IOP spike; one early hyphema; five cases of postoperative hypotony, two of which had a positive Seidel test from the conjunctival suture; three cases of transient choroidal detachment, two of which had shallow anterior chamber. No patient required reoperation. Two eyes required argon laser suture lysis, and nine underwent one or more 5-FU injections, which caused punctate keratopathy in three eyes. CONCLUSIONS: Viscocanalostomy is an effective IOP-lowering procedure in white adults affected by open-angle glaucoma. Trabeculectomy with postoperative 5-FU can probably provides lower IOPs but, with more numerous complications, greater discomfort, and more intensive postoperative management.