Tied Tube Trial in Glaucoma Surgery

The aim of this study is to assess whether delaying early flow through the Ahmed tube shunt may improve the post-operative surgical outcomes and provide a more predictable outcome. To assess this the investigator will conduct a, randomized prospective, multi-centered study with collaborators at WashU in St. Louis, Duke University, Indiana University and the University of Pittsburgh. Participants will be randomized to have an AGV placement with tube ligation (no-early flow) and without ligation (allowing for early flow). IOP will be measured at day one, week one, and months, one, three six, and twelve. Additionally, clinical data regarding number of glaucoma medications, and complications post-operative complications will also be collected.

Inclusion Criteria:Subjects with age at screening ≥ 18 yearsInadequately controlled glaucoma or ocular hypertensionAhmed valve implant as the planned surgical procedurePatients with primary glaucomas (Primary Open Angle Glaucoma or Primary Angle Closure Glaucoma) or pseudoexfoliation, pigmentary and traumatic glaucoma with or without a previous failed trabeculectomy or other intraocular surgery.Primary tubes includedInvestigators to recruit consecutively all eligible patients from their clinics.Capable and willing to provide consentExclusion Criteria:Subjects with NLP visionSubjects unable/unwilling to provide informed consentUnavailable for regular follow upPrevious cyclodestructive procedurePrior scleral buckling procedure or other external impediment to drainage device implantationPresence of silicone oilVitreous in the anterior chamber sufficient to require a vitrectomyUveitic glaucomaNeovascular glaucomaNanophthalmosPatients with pathology that may cause elevated episcleral venous pressureProcedure combined with ocular surgery other than cataract surgery (i.e. combined tube-cataract surgery is okay)Any abnormality other than glaucoma in the study eye that could affect tonometry.