Impact of Glucagon-Like Peptide 1 (GLP-1) and Gastric Inhibitory Polypeptide (GIP) Receptor Agonists on Intraocular Pressure in Glaucoma: A Case Series

PURPOSE: Glucagon-Like Peptide 1 Receptor Agonists (GLP-1RAs) are antidiabetic and weight management medications that bind to GLP-1 receptors throughout the body. Growing interest in this class has led to several retrospective cohort studies reporting a decreased occurrence of glaucoma in diabetic and non-diabetic patients with the use of GLP-1RAs, suggestive of anti-inflammatory and neuroprotective effects. Here we report five real world cases evaluating the impact of GLP-1RA and dual GLP-1/Gastric Inhibitory Polypeptide (GIP) receptor agonist use on Intraocular Pressure (IOP) measurements and subsequent disease management in glaucoma patients. OBSERVATIONS: Case 1 (severe pigment dispersion glaucoma OU) was started on semaglutide on two separate occasions and exhibited clinically significant declines in home IOP tonometry readings after each initiation (OD max: 20 to 18, 16 to 14; OS: 22 to 15, then 20 to 17). Case 2 (severe primary open angle glaucoma OU) was a candidate for filtration device surgery when he began taking tirzepatide, after which a decrease in home IOP tonometry readings was observed (OD: 11 to 8; OS: 21 to 14), resulting in surgery postponement. Case 3 (secondary glaucoma OD following trauma) began taking tirzepatide shortly following glaucoma drainage device implantation and experienced unexplained hypotony (IOP: 25 to 4). Case 4 (severe POAG OU) was taking semaglutide with stable IOPs until pancreatitis prompted cessation of semaglutide, whereupon an increase in IOP was subsequently observed (OD: 23 to 30; OS: 16 to 18). Case 5 (undiagnosed) is a patient naïve to IOP-lowering therapy and initiation of tirzepatide correlated with an abrupt reduction in IOP observed in clinic (OU: 24 to 10). CONCLUSION AND IMPORTANCE: These cases demonstrate a potential association between GLP-1/GIP receptor agonist use and IOP lowering in patients with glaucoma and help substantiate existing literature with real world cases, thereby highlighting the need for further prospective research on this emerging topic.