Glucagon Agonist Therapies and Vision Loss: Balancing Promise with Prudence in India

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dual incretin therapies such as tirzepatide have transformed the management of type 2 diabetes mellitus and obesity, with expanding cardiometabolic indications and rapid market growth globally and in India. However, emerging postmarketing evidence has raised concerns regarding ocular safety. Pharmacovigilance analyses, cohort studies, and case reports suggest an association between GLP-1-based therapies and ophthalmic adverse events, including early worsening of diabetic retinopathy and, more concerningly, nonarteritic anterior ischemic optic neuropathy (NAION)-a potentially irreversible cause of sudden vision loss in adults over 50 years. Although the absolute risk appears very low, regulatory agencies, including the WHO and European Medicines Agency, now recognize NAION as a very rare adverse effect of semaglutide, and similar signals are being explored for other agents, suggesting a possible class effect. Proposed mechanisms include altered optic nerve head perfusion, sympathetic-mediated vasoconstriction, and rapid glycemic shifts affecting vascular autoregulation; however, causality remains unproven. In India, where over 100 million adults live with diabetes and obesity rates are rising, even rare adverse events may translate into substantial public health impact, particularly given limited access to ophthalmic care and increasing unsupervised drug use. We advocate a balanced approach: baseline ophthalmic evaluation in high-risk individuals, informed consent regarding visual symptoms, early referral for visual complaints, strengthened pharmacovigilance, and coordinated endocrinology-ophthalmology surveillance systems. As newer triple agonists approach clinical use, integrating ocular safety into prescribing frameworks is imperative. Metabolic gains must not come at the cost of preventable vision loss.