RecruitingPhase 4Drug trialA Study Investigating Oral Semaglutide in People with Open-Angle GlaucomaThe aim of this clinical trial is to investigate whether oral semaglutide can be used to treat open-angle glaucoma. The main question it aims to answer is: Does oral semaglutide safely improve inner retinal function in patients with open-angle glaucoma as measured by the photopic negative response of the electroretinogram. Researchers will compare oral semaglutide to a placebo (a look-alike substance that contains no drug). Participants will: * Take semaglutide or a placebo every day for 6 months. * Visit the clinic 5 times in total for tests and interviews: At baseline (the first day they are included in the study), after 1 month, after 2 months, after 3 months, and after 6 months (the last day they are included in the study).