The objective of this study is to evaluate the postoperative best corrected visual acuity and refraction in 2 different filtering glaucoma surgeries: XEN implant standalone procedure versus classic trabeculectomy standalone procedure. Both procedures are standard of care in surgical treatment of glaucoma. The XEN implant is a minimally invasive procedure and spares out the dissection of the conjunctiva, while the classic trabeculectomy is a procedure ab externo and supposed to be more invasive.~Up to 196 eyes will be enrolled in both surgery groups. Patients have to be legible for both procedures and are randomly allocated to both groups. Patients, who need a combined cataract procedure are not legible.~A prospective, randomized, multicenter trial. Four study centers in Europe (Austria) will participate.~Patients with open angle glaucoma will be screened for eligibility, and informed consent will be obtained from those who meet screening criteria and are interested in participating in the study. Eligible patients will be examined preoperatively to obtain a medical history and to establish a baseline for the ocular condition. During screening it will be determined via randomization if the subject will be included in group 1 where the XEN implant will be implanted in a standalone procedure or in group 2 where the trabeculectomy will be performed in a standalone procedure. Regardless of study group, all eligible patients will have the same inclusion/exclusion criteria, effectiveness endpoints and follow up exams. An inclusion of both eyes of the same patient is not possible.~Postoperatively, subjects will undergo ophthalmic evaluations at regular intervals as specified in this protocol.~The objective of this study is to evaluate the postoperative best corrected distance and near visual acuity and refraction in 2 different filtering glaucoma surgeries: XEN Implant standalone procedure versus classic trabeculectomy standalone procedure.~The primary endpoint is the proportion of patients with a best corrected distance visual acuity > 0.3 (logMAR) after 1 week.~Secondary objectives are the distance and near best corrected visual acuity measured at postoperative visits (e.g. day 1, month 1, 3, 12) and relative change of visual acuity at postoperative visits compared to baseline in both groups (e.g. month 1). The proportion of patients with a loss of best corrected distance visual acuity ≥ 2 lines at postoperative visits (e.g. day 1), the proportion of patients with a best corrected distance visual acuity (logMAR) > 0.3 and > 0.5 will be assessed at different postoperative visits (e.g. week 1, 2, month 1 and 3). Additionally, the time of recovery of visual acuity and the postoperative changes of refraction after the procedures will be compared. Secondary endpoints also include efficacy and safety of both procedures.~Subjects will undergo study visits at the following times: Preoperative Visit 1 (Screening), Operative Visit 2, 1 Day, 1 Week, 2 Weeks, 1 Month, 3, 6 Months, 12 Months Visit.
Multicentric evaluation of best corrected visual acuity of the XEN implant versus classic trabeculectomy in open angle glaucoma subjects