Combined argon laser peripheral iridoplasty and Nd: YAG laser shock wave therapy for recurrent XEN gel stent obstruction due to iris incarceration

Abstract

Introduction: Despite its proven effectiveness and safety profile, the XEN Gel Stent (Allergan Inc., CA, USA) has a small lumen and is therefore likely to become occluded by fibrin, a blood clot, or even the iris. However, few studies have investigated XEN-iris occlusion and how to manage this condition. We describe the first case report of recurrent XEN gel stent obstruction by iris incarceration, which was resolved following a combined treatment with argon laser peripheral iridoplasty (ALPI) and low-energy neodymium-doped yttrium aluminum garnet (Nd: YAG) laser shock wave treatment.Patient information: A 74-year-old Korean male underwent uncomplicated XEN gel stent implantation and presented with low intraocular pressure (IOP) with a well-functioning filtering bleb during the first postoperative week. On postoperative day 10, the XEN lumen was occluded by the iris and demonstrated an IOP spike of 33 mmHg. Despite the use of pilocarpine, the iris incarceration persisted. Therefore, surgery to reposition the XEN stent was attempted using a gonio-prism and intraocular forceps. After the first revision surgery, the IOP and stent position were stable for 2 weeks. However, recurrent partial obstruction of the stent by the iris, pigment dispersion into the intraluminal space, and an elevated IOP of 24 mmHg were observed later.Diagnosis: Recurrent XEN gel stent occlusion by the iris and intraluminal pigment dispersion.Interventions: Combined ALPI and low energy Nd: YAG laser shock wave therapy.Outcomes: IOP dropped from 24 mmHg to 10 mmHg immediately and continued to be well-controlled until 3 months later (range: 8-12 mmHg).Conclusions: To the best of our knowledge, this is the first case report of the efficacy of combined laser treatment for relieving recurrent XEN implant occlusion by the iris. This combination laser treatment might be a relatively safe rescue treatment to restore the patency of a XEN gel stent occluded by the iris, even in cases with recurrent XEN stent obstruction after surgical repositioning.Abbreviations: AC = anterior chamber, ALPI = argon laser peripheral iridoplasty, AS-OCT = anterior segment optical coherence tomography, IOP = intraocular pressure, Nd: YAG = neodymium-doped yttrium aluminum garnet.

Iris Obstruction Following PRESERFLO™ Microshunt Implantation and Surgical Management

“…In contrast, in case of iris obstruction, only the use of YAG or argon laser has been previously described. [11][12][13][14][15][16] PMS touching the iris have also been reported in the literature and are present in around 2%−13% of the cases, most of which without any consequences for the IOP or postoperative management. 3,5 Scheres et al 3 described repositioning of the PMS as management for iris obstruction.…”

“…In case of blood clot or vitreous entrapment, the most often proposed therapeutical option consists of surgical removal of the obstruction with forceps. In contrast, in case of iris obstruction, only the use of YAG or argon laser has been previously described 11–16…”

Tube obstruction caused by intraocular lens capture following PreserFlo MicroShunt implantation

“…Tube occlusion caused by iris, blood clot, vitreous or anterior capsule after glaucoma drainage device surgeries has been reported in several previous reports. 18 , 19 , 20 , 21 , 22 , 23 , 24 For any type of tube occlusion, surgical procedure and laser therapy using YAG or argon laser are the preferred treatment options. The surgical procedure includes release of the tube occlusion using forceps in the anterior chamber, anterior vitrectomy or pars plana vitrectomy.…”

Iris-Occlusion of XEN Gel Stent following Ab Externo Transconjunctival Implantation Technique

“…Several treatment modalities for iris-occluded XEN gel stent have also been described in the current literature. One case describing management of this complication reported reoccurrence of occlusion following surgical repositioning of XEN, but successful resolution of occlusion with combined treatment with argon laser peripheral iridoplasty and low energy neodymium-doped yttrium aluminum garnet laser [ 6 ]. Another report describes successful resolution of occlusion with argon laser peripheral iridoplasty alone [ 7 ].…”