About the DECLARE Trial

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 (GDD) implantation with the drainage tube placed in the anterior chamber (front part of the eye) or the sulcus (small space between iris and lens of the eye) in efforts to minimize corneal cell loss in the eye. The trial will also compare intraocular pressure (IOP) and metagenomics RN deep sequencing (MDS) between sulcus and anterior chamber (AC) tube placement after GDD implantation.

The primary outcome assessment will be at 12 months after GDD implantation, and trial participants will continue to be followed for 24 months.

A total of about 226 patients will be enrolled in the study at 6 clinical centers:

The University of California, San Francisco, CA
Bascom Palmer Eye Institute, Miami, FL
Johns Hopkins University, Baltimore, MD
Massachusetts Eye and Ear, Boston, MA
Prism Eye Institute, Toronto, Canada
University at Buffalo/State University of New York, Buffalo, NY

The participants will be randomized 1:1 to either:

Sulcus tube placement
AC tube placement

Rationale for the study:

Glaucoma drainage device (GDD) surgery has gained popularity in managing patients with medically uncontrolled glaucoma, the leading cause of irreversible blindness in the world. However, one of the major long-term complications of GDD is progressive corneal endothelial cell loss (ECL) leading to corneal decompensation, which requires complex care.

One mechanism for ECL after GDD implantation is direct mechanical damage from the silicone tube in the anterior chamber (AC), the most common location for tube placement. To address this concern, surgical techniques have been modified to insert the tube into the ciliary sulcus, which offers the advantage of increased distance between the cornea and the tube, with the iris acting as a barrier between the two. Yet despite theoretical advantages, AC tube placement remains the preferred location, as there is a lack of convincing data to validate the advantages of cornea protection and surgical outcomes with sulcus placement.

A well-designed randomized controlled trial (RCT) is needed to determine which location of tube placement leads to less ECL while providing safe and effective surgical outcomes.

Specific Aims of the Study:

Aim 1: To compare endothelial cell loss after GDD implantation with tube placement in the ciliary sulcus versus the anterior chamber. This aim focuses on studying corneal health. We hypothesize that subjects with sulcus tube placement will have less ECL compared to subjects with tube placement in the AC. Anterior segment OCT will be applied to investigate the relationship between tube position and ECL with additional consideration of anterior chamber depth.

Aim 2: To compare intraocular pressure control after GDD implantation with tube placement in the ciliary sulcus versus the anterior chamber. This aim focuses on GDD surgical outcomes. We hypothesize that subjects with sulcus tube placement will have similar IOP control compared to subjects with tube placement in the AC. We will also assess other outcomes, including visual acuity, number of anti-glaucoma medications and intra- and post-operative complications.

Aim 3: To compare AC microenvironment after GDD implantation with tube placement in the ciliary sulcus versus the anterior chamber using metagenomic RNA deep sequencing (RNA-seq). We hypothesize that there are unique gene expression profiles or biomarkers from aqueous samples of subjects with the tube placed in the sulcus versus the AC. We will also correlate the RNA-seq results with ECL.