Subconjunctival Ab Externo Gel Stent Implantation for Refractory Glaucoma After High-Risk Penetrating Keratoplasty

This case study reports the successful deployment of the XEN45 gel stent (AbbVie Inc, Chicago, IL) through an ab externo approach in a 73-year-old woman with refractory glaucoma following high-risk penetrating keratoplasty (PK) 10 years prior. The PK was for corneal perforation secondary to peripheral ulcerative keratitis, which required systemic immunosuppression comprising intravenous cyclophosphamide, azathioprine, and corticosteroids to stabilise the disease and prevent corneal graft rejection. The patient's intraocular pressure was reduced from 40 mmHg preoperatively to 12 mmHg six months after surgery, off medication. The patient's visual acuity and visual fields remained stable. The XEN45 gel stent utilising the ab externo approach can be considered as a potential tool to lower intraocular pressure in patients with glaucoma after corneal keratoplasty.