Aqueous misdirection syndrome following ab interno gelatin stent can be managed successfully with anterior vitrectomy approach

Introduction: Minimally invasive glaucoma surgery (MIGS) is a relatively new surgical technique available to glaucoma surgeons. The ab interno gelatin XEN stent (XEN®45, Allergan Inc., CA, USA) drains aqueous into the subconjunctival space and is theoretically less invasive than trabeculectomy and therefore carries less risk. Aqueous misdirection syndrome (AMS) is a rare but well-recognised complication of any intraocular surgery. Only four cases have been reported following XEN stents but their management and outcome was not discussed. We present a case of AMS following XEN implantation including management and outcome. Case presentation: A 78 year old lady with an axial length of 21.27 mm and a previous episode of acute angle closure glaucoma was treated with laser peripheral iridectomy and, later, clear crystalline lens extraction. However, she continued to have high intraocular pressure (IOP) and a shallow anterior chamber. Despite medical therapy, she developed worsening glaucoma. She had XEN implantation to her right eye with no intraoperative complication. Unfortunately, she developed signs of AMS. Medical and laser zonulohyaloidectomy failed to resolve the condition. She then had surgical iriodozonulohyaloidectomy and anterior vitrectomy which resolved the AMS. Discussion: Management of AMS has been well documented. However, incidence following novel surgical techniques, such as XEN implantation, is not well reported. We have shown that AMS following XEN can be successfully treated using an anterior approach.