Bence Tasnadi

Glucagon-like peptide-1 (GLP-1) receptor agonists, such tirzepatide and semaglutide, have evolved from specialised diabetes treatments to household brands in recent years. The UK’s approach to obesity and type 2 diabetes has changed as a result of its powerful effects on appetite suppression, weight loss, and glycaemic management, with prescriptions increasing in both private clinics and NHS services (1). Although metabolic and cardiovascular benefits have received most of the emphasis in public and professional discourse, another organ system deserves further consideration: the eyes. Understanding GLP-1 receptor agonists’ possible ocular effects – both positive and negative – is becoming more crucial as their use rises.

It is commonly known that metabolic disorders and eye health are related. Due in large part to diabetic retinopathy and diabetic macular oedema, diabetes continues to be a major cause of visual impairment in working-age adults in the UK (2). Retinal disease progression is linked to poor glycaemic management, greater disease duration, and fast blood glucose changes. GLP-1 receptor agonists have the potential to improve long-term ophthalmic results by enhancing glycaemic management and encouraging substantial weight loss. The risk of microvascular problems, especially those affecting the retina, may be decreased by improved metabolic profiles.

The idea of a net systemic benefit is supported by the fact that multiple major cardiovascular outcome trials of GLP-1 receptor agonists have shown overall decreases in diabetes-related complications (3). From an optical standpoint, improved glycaemic stability over time is probably going to cause many patients’ diabetic retinopathy to grow more slowly. Retinal vascular health may also be enhanced by weight loss and improvements in blood pressure and lipid profiles. In this regard, an indirect but significant improvement in population eye health may be represented by the increasing usage of GLP-1 medications.

The visual narrative is not totally clear-cut, though. Concerns regarding a higher incidence of complications from diabetes retinopathy in specific patient groups were raised by early findings from large trials, most notably the semaglutide SUSTAIN-6 trial

(4). Those with pre-existing retinopathy who saw quick and significant drops in HbA1c seemed to exhibit the highest signal. Many experts feel this represents the well-known occurrence of “early worsening” of diabetic retinopathy following quick improvement in glycaemic management, rather than implying a direct harmful action of GLP-1 receptor agonists on the retina.

With aggressive insulin therapy, this idea has been seen before and is not new. Before longer-term advantages become apparent, abrupt blood glucose normalisation may temporarily worsen retinal microvascular alterations. However, this danger may be underestimated when it comes to GLP-1 receptor agonists, especially since these drugs are being provided more frequently outside of conventional speciality diabetes clinics. Patients receiving therapy through private weight-loss services might not receive sufficient counselling regarding possible visual issues or undergo routine retinal screening.

There is still little information on GLP-1 receptor agonist-related ocular adverse effects other than diabetic retinopathy. Although there is a paucity of large-scale data and unclear causality, case studies have described transitory visual abnormalities. Though the clinical implications of this is still unknown, preclinical research indicates that GLP-1 receptors may be present in retinal tissue, generating theoretical concerns regarding direct retinal effects (5). Although there is currently not enough data to indicate that these medications provide a significant risk of non-retinal ocular pathology, post-marketing surveillance will be crucial as exposure rises.

Thus, there are opportunities and challenges for eye health associated with the growing usage of GLP-1 receptor agonists. Overall, many patients are likely to experience long-term ocular benefits from improved metabolic regulation. However, the possibility of early retinopathy progression in vulnerable individuals emphasises the significance of rigorous retinal screening, careful patient selection, and gradual glycaemic correction when feasible. To guarantee that individuals at risk are effectively managed, there must be clear contact between primary care, diabetes services, and ophthalmology.

In conclusion, GLP-1 receptor agonists’ effects on eye health need more consideration as they continue to transform the way type 2 diabetes and obesity are managed in the UK. Potential short-term dangers should not be disregarded even though the overall effect might be favourable, especially in terms of lowering long-term microvascular problems. To maximise benefit while limiting damage, it will be essential to keep “eyes on” GLP-1 medicines through research, surveillance, and interdisciplinary care.

References

1. Marso SP, Daniels GH, Brown-Frandsen K, Kristensen P, Mann JF, Nauck MA, et al. Liraglutide and cardiovascular outcomes in type 2 diabetes. N Engl J Med. 2016;375(4):311–22.
2. Scanlon PH. The English National Screening Programme for diabetic retinopathy 2003-2016. Acta Diabetol. 2017;54(6):515–25.
3. Vilsbøll T, Bain SC, Leiter LA, Lingvay I, Matthews D, Simó R, et al. Semaglutide, reduction in glycated haemoglobin and the risk of diabetic retinopathy. Diabetes Obes Metab. 2018;20(4):889–97.
4. Hernández C, Bogdanov P, Corraliza L, García-Ramírez M, Solà-Adell C, Arranz JA, et al. Topical administration of GLP-1 receptor agonists prevents retinal neurodegeneration in experimental diabetes. Diabetes. 2016;65(1):172–87.