Xen45 gel stent ab interno trimming for ostium occlusion: case report

Background Despite the XEN gel stent low-risk profile, various complications following the implant have been described, including internal and external occlusion, with a consequent postoperative rise in intraocular pressure (IOP). In this case report we aimed to present a XEN45 stent internal occlusion successfully treated by trimming in situ its proximal end with a 25 G vitreous scissors using a bimanual technique. Case presentation A 63-year-old male patient affected by primary open angle glaucoma (IOP = 25 mmHg) and a full thickness macular hole in his right eye, underwent ab-interno Xen gel stent implantation and, 1 month later, a 25 G vitrectomy surgery. Despite a significant IOP reduction after stent implant, 6 days after vitrectomy, IOP increased (25 mmHg) and the conjunctival bleb flattened following occlusion of stent internal ostium by a clot of presumed fibrinous material. The Nd:YAG laser failed to remove the clot, so that we decided to snip a small bit of the proximal end of the Xen tube (about 0,5 mm length) with a 25 G vitreous scissors, using a bimanual technique. In the postoperative day 1 and month 1, the IOP was 8 mmHg and 12 mmHg, respectively. The Anterior Segment OCT confirmed a functional, layered, filtering bleb, and the normal appearance and patency of the XEN proximal segment. No side effects from the intervention were observed. Conclusions Ab interno trimming with vitreous scissors of the occluded proximal end of the XEN stent may represent a safe, rapid and efficient method to restore aqueous humor subconjunctival drainage.

Conjunctival bleb tearing by XEN gel stent after conjunctival compression sutures

Purpose: As minimally invasive glaucoma surgery devices emerge, newer complications are reported. XEN gel stent is safer than classic glaucoma surgery but may also lead to severe adverse effects as hypotony. Compression conjunctival sutures are a useful treatment for overfiltration hypotony after XEN gel stent implantation, but might force bleb tearing by the implant as it gets tightly close to the sutured conjunctiva. This complication has not been previously reported. Methods: We report a patient with overfiltration hypotony after XEN gel implantation. Conjunctival compression sutures and implant relocation ab interno were performed obtaining a good outcome. As conjunctiva got tightly close to the stent, the device eroded the bleb so leakage and implant extrusion were found. Results: Bleb reconstruction by conjunctival autograft was performed in order to avoid hypotony due to continuous conjunctival leakage. Conclusion: Conjunctival compression sutures may be used for overfiltration control after XEN gel implantation but we must be aware of potential conjunctival damage due to implant erosion even if it is correctly positioned. Close follow-up and early suture release may be convenient in these patients.

Minimally Invasive Glaucoma Surgery: A Critical Appraisal of the Literature

Micro- or minimally invasive glaucoma surgeries (MIGS) have been the latest addition to the glaucoma surgical treatment paradigm. This term refers not to a single surgery, but rather to a group of distinct procedures and devices that aim to decrease intraocular pressure. Broadly, MIGS can be categorized into surgeries that increase the trabecular outflow [Trabectome, iStent (first and second generations), Hydrus microstent, Kahook Dual Blade and gonioscopy-assisted transluminal trabeculotomy], surgeries that increase suprachoroidal outflow (Cypass microstent and iStent Supra), and conjunctival bleb-forming procedures (Xen gel stent and InnFocus microshunt). Compared to traditional glaucoma surgeries, such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves), MIGS are touted to have less severe complications and shorter surgical time. MIGS represent an evolving field, and the efficacy and complications of each procedure should be considered independently, giving more importance to high-quality and longer-term studies.

Delayed Onset Scleromalacia and Conjunctival Bleb Formation Following Intraoperative Mitomycin C Application during Conjunctival Melanoma Excision

Purpose: To present a case of delayed onset scleromalacia and conjunctival bleb formation one year after conjunctival melanoma excision with intraoperative use of mitomycin-C (MMC) and double-freeze-thaw technique. Methods: Case report. Results: A 69-year-old woman had a conjunctival melanoma excised by the ‘no touch technique’ with intraoperative application of 0.02% MMC for 3 min on bare sclera, freeze-thaw cryotherapy and amniotic membrane transplant performed elsewhere. Three months later, she presented to us with a red, sore and painful right eye. Examination revealed severe scleritis. She was treated with lubricants and oral steroids for 6 weeks. She settled well with no recurrence of melanoma. At one year, she developed scleromalacia and conjunctival blebs in the inferonasal quadrant of right eye. She remains under closer observation as she is at high risk of perforation. Conclusion: Caution should be exercised with intraoperative use of MMC on bare sclera during excision and cryotherapy of conjunctival melanoma. As published in the literature, when using MMC, it is recommended to use the lowest dose topically in the form of eye drops in the postoperative period for the shortest time to avoid any sight-threatening complications.

Transscleral cyclophotocoagulation and its histological effects on the conjunctiva

Micropulse transscleral cyclophotocoagulation (MP-TCP) is increasingly being used as an initial procedure prior to conjunctival filtration surgeries. However, it is uncertain whether MP-TCP may cause inflammation and scarring of the bulbar conjunctiva. Thus, we aimed to study the histological effects of MP-TCP (compared to controls and continuous wave [CW]-TCP) on the conjunctiva. Our study included 10 Dutch Belted Rabbits that underwent TCP in their right eyes (n = 5, MP-TCP; n = 5, CW-TCP), while their left eyes served as controls. The rabbits were euthanised at 4 weeks, and their dissected globes underwent histopathological and immunohistochemical examination. We observed greater conjunctival inflammation in MP-TCP or CW-TCP-treated eyes compared to controls, but not between each other. The majority of the lymphocytic infiltrates were CD4 T-cells. Increased conjunctival fibrosis was evident in MP-TCP or CW-TCP-treated eyes, to similar extents, compared to controls. However, the increased staining for myofibroblasts was not statistically significant in TCP-treated eyes. We concluded that MP-TCP causes significantly greater overall conjunctival inflammation and scarring compared to controls, similar to CW-TCP. As these are risk-factors for fibrosis and failure of the conjunctival bleb, further studies are required to explore the effect, if any, of post-TCP conjunctival changes on future bleb morphology and survival.

Conjunctival bleb compression as a treatment for hypotony post XEN45 implant in uveitic glaucoma

Purpose: Over-filtration and subsequent hypotony are recognised complications of penetrating glaucoma procedures, especially when augmented with antimetabolites. Patients with uveitis are especially at risk of hypotony and this can reduce the final acuity achieved, compromise surgical outcomes and adversely affect the inflammatory status. The incidence of hypotony following XEN45 implant insertion is higher for uveitic patients and we present a method of surgically addressing this hypotony with transconjunctival compression sutures that are placed over the overdraining XEN45 implant. Methods: We present a retrospective case series of consecutive uveitic glaucoma patients who had conjunctival compression sutures between 2015 and 2018 following XEN45 insertion, at the Manchester Royal Eye Hospital, UK. Two 9/0 nylon sutures were placed in a horizontal figure-of-eight conformation transconjunctivally across the overdraining bleb: one directly over the XEN45 implant and one at the posterior limit of the implant in order to restrict flow. Results: Three patients underwent conjunctival compression sutures following XEN45 implant-related hypotony and all three had successful resolution of their hypotony and visual symptoms. No patients required long-term topical agents to control their intraocular pressure. Conclusion: Conjunctival compression sutures are an effective option for addressing persistent hypotony following XEN45 implant insertion in patients with uveitic glaucoma.

Correlation between Tissue Characterization and Dynamic Expression of Matrix Metalloproteinase-2 and Its Tissue Inhibitor in Conjunctival Filtering Bleb of Rats

Purpose.Using rat conjunctival bleb model, we correlated changes morphology and histology in the bleb with changes in MMP-2 and TIMP-2 levels.Methods.Filtering surgeries were performed on rats. Dynamic changes in morphology and histopathology were observed using HE staining. Expression of MMP-2 and TIMP-2 was determined by immunofluorescence microscopy and western blotting.Results. Well-elevated filtering blebs formed and persisted for an average of 12 days. Histological examination showed that inflammatory was dominant in postoperative days 1–3, and proliferating manifestation became the main sign 5 days later. Western blot showed that MMP-2 was downregulated 1 day after surgery, upregulated at 3 days, and observed with a peak at 7 days; then it persisted until 28 days. The difference was statistically significant (F= 280.18,p<0.01).TIMP-2 was upregulated 1 day after surgery and observed with a peak at 5 days; then it persisted until 28 days. The difference was statistically significant (F= 145.34,p<0.01).Conclusions.During the processes of conjunctival filtering bleb and scar formation in rats, the changes in MMP-2 and TIMP-2 levels in the filtering area, together with a corresponding proliferation of fibroblasts and the accumulation of collagen fibres, resulted in scarring of filtering blebs.

Clinical Research of Ultrasound Ciliary Plasty and Implications for Clinical Practice

Ultrasound ciliary plasty (UCP) is a novel, non-invasive procedure for the control of intraocular pressure (IOP) in patients with openangle glaucoma (OAG), and is particularly useful for refractory glaucoma after failed filtering surgery and patients with elevated risk of surgical failure due to high risk of conjunctival bleb scarring. A meta-analysis was performed of seven clinical trials, involving 251 patients, which evaluated the efficacy and safety of the procedure. The procedure was effective in reducing mean IOP across all indications and IOP reductions were similar in patients with refractory and non-refractory glaucoma. Safety and tolerability were good, with conjunctival hyperaemia being the most common side effect. Serious complications were rare. Procedures using the second-generation therapy probe were associated with superior reproducibility of IOP reduction compared with the first-generation probe. In summary, the procedure is a promising and effective treatment option for patients with refractory and non-refractory OAG.