Glaucoma Drainage Device and Endothelial Cell Loss Compare Trial (DECLARE) is a multi-center, outcome-masked, randomized clinical trial. The purpose of this study is to compare glaucoma drainage device implantation in the anterior chamber (front part of the eye) and sulcus (small space between iris and front chamber of the eye) in efforts to minimize cell loss in the eye.

The DECLARE Trial is a prospective 1:1 randomized, parallel design, double-masked clinical trial to compare endothelial cell density (ECD), intraocular pressure (IOP) and metagenomic RNA deep sequencing (MDS) between sulcus and anterior chamber (AC) tube placement after glaucoma drainage device (GDD) implantation.

The trial has fixed sample size with 12 months follow-up for primary outcome assessment and trial participants will continue to be followed to the end of grant cycle with a total of 24 months follow-up.

Patients will be randomized to 2 tube locations for GDD implantation:

• Tube placed in the AC
• Tube placed in ciliary sulcus
• Stratification: by clinical center and type of surgery (GDD alone vs GDD combined with phacoemulsification). Stratified randomization by clinical center is to ensure that a similar number of subjects will be randomized to either sulcus tube or AC tube placement for a specific clinical center. Because eyes undergoing a combined phacoemulsification with GDD implantation may be associate with larger ECL from phacoemulsification, stratified by surgery type is to ensure two tube location groups similar number of study eyes that will undergo a combined phacoemulsification with GDD implantation.

Inclusion Criteria:

• Medically uncontrolled glaucoma requiring GDD or GDD combined with phacoemulsification as the planned surgical procedure
• Candidate for GDD implantation for ciliary sulcus and AC tube
• Age greater than or equal to 18 years old

Exclusion Criteria:

• Preexisting corneal condition that would affect the corneal endothelium or previous corneal transplant
• Presence or history of Cypass Micro-Stent
• Previous GDD, Xen Gel Stent or Preserflo MicroShunt removed less than 6 months before surgery
• Presence of GDD implantation, Xen Gel Stent, of Preserflo MicroShunt
• Previous trabeculectomy and/or minimally invasive glaucoma surgery within the past 6 months
• AC intraocular lens
• Presence of nanophthalmos, uncontrolled uveitis, silicone oil, Sturge-Weber syndrome or other conditions associated with elevated episcleral venous pressure
• Unwilling or unable to give consent, unwilling to accept randomization, or unable to return for scheduled protocol visits
• No light perception vision in the study eye or fellow eye visual acuity < 20/200
• Need for glaucoma surgery combined with other ocular procedures (i.e. corneal transplant, or retinal surgery) or anticipated need for additional ocular surgery

All trial participants will be masked to their tube locations. The primary outcome accessors who grade specular microscopy images at the PRC, perform IOP measurements at each clinical center, or conduct the MDS analysis at the Metagenomic RNA Deep Sequencing (RNA-seq) Center will also be masked to tube locations. Due to the nature of the surgical intervention, the surgeon, the technician taking specular microscopy and AS-OCT images, and the graders at the PRC who will perform AS-OCT measurements will not be masked to the tube locations. However, the graders of AS-OCT images will be masked to the purpose of the study and will be different from the graders of specular microscopy images.