The American Glaucoma Society (AGS) Second Aqueous Shunt Implant vs. Transscleral Cyclophotocoagulation Treatment Study (ASSISTS)

Inclusion Criteria: * Women and men 18 to 85 years of age * Glaucoma not adequately controlled (IOP \>18 mmHg on maximum tolerated topical therapy) with a single aqueous shunt (AS). * Best-corrected visual acuity (BCVA) of hand motion (HM) or better in the study eye Exclusion Criteria: * Monocular * Presence of more than one AS in the study eye * Previous cyclodestruction in the study eye * Presence of active iris neovascularization in the study eye * Binocular diplopia * Presence of scleral buckle in the study eye * History or scleritis in either eye * History of scleromalacia in the study eye * Insufficient conjunctiva to cover AS in the study eye * IOP cannot be accurately measured with Goldmann applanation, Pneumotonometry, or Tono-Pen in the study eye * Presence of silicone oil in the study eye * Presence of retinal detachment in the study eye * Presence of intraocular or orbital tumor affecting the study eye * Need for cataract extraction or concurrent procedure at the time of study treatment, except tectonic aqueous shunt revisions for both groups is allowed. * In the opinion of the investigator, should not be enrolled in this study * Unwilling or unable to give consent and satisfy requirements of the study