Clinical Research Directory

Inclusion Criteria: * Subjects with age at screening ≥ 18 years * Inadequately controlled glaucoma or ocular hypertension * Ahmed valve implant as the planned surgical procedure * Patients 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 included * Investigators to recruit consecutively all eligible patients from their clinics. * Capable and willing to provide consent Exclusion Criteria: * Subjects with NLP vision * Subjects unable/unwilling to provide informed consent * Unavailable for regular follow up * Previous cyclodestructive procedure * Prior scleral buckling procedure or other external impediment to drainage device implantation * Presence of silicone oil * Vitreous in the anterior chamber sufficient to require a vitrectomy * Uveitic glaucoma * Neovascular glaucoma * Nanophthalmos * Patients with pathology that may cause elevated episcleral venous pressure * Procedure 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.