The gonio scratch study: methodology of a multicenter clinical trial establishing a new minimally invasive glaucoma surgery.

There are numerous surgical procedures for glaucoma. Minimally invasive glaucoma surgery is becoming popular; however, the disadvantage is the high incidence of anterior chamber hemorrhage. Heavy bleeding can also lead to increased intraocular pressure (IOP) postoperatively. Gonio scratch is a surgical procedure that improves aqueous humor outflow by rubbing off deposits on the trabecular meshwork with a Diamond Dusted Sweeper. As the conjunctiva and trabecular meshwork are not incised, no postoperative bleeding is expected, and the IOP spike will be minimal. We designed this study to determine the efficacy and safety of gonio scratch. This is an on-going multicenter, prospective, clinical trial. Patients who are scheduled for glaucoma surgery with or without cataract surgery are being enrolled. A total of 80 eyes will be recruited in the Hiroshima University Hospital, Miyoshi Eye Clinic, Yokoyama Retina Clinic, and Kusatsu Eye Clinic. All patients will undergo gonio scratch. When combined with cataract surgery, gonio scratch is performed after the intraocular lens is inserted. The primary study endpoint is the change in IOP from baseline to 1 year after surgery. The secondary endpoints are complications, number of glaucoma medications, surgical time, and changes in visual acuity and the visual field. This study protocol was approved by the institutional review board of Hiroshima University. The trial results will be shared with the scientific community at international conferences and by publication in a peer-reviewed journal. Trial registration number is jRCTs062200003.