GLP-1R Agonists Improve Ocular Surface Parameters in Type 2 Diabetes Mellitus

Dry eye disease (DED) is a prevalent ocular surface disorder frequently associated with type 2 diabetes mellitus (T2DM). While glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have demonstrated systemic anti-inflammatory and vascular benefits beyond glycemic control, their potential impact on tear film parameters remains largely unexplored. This study aimed to evaluate the effects of GLP-1 RAs on ocular surface health in patients with T2DM.

In this single-center case-control study, 35 patients with T2DM receiving glucose-lowering therapies were enrolled. Participants were divided into two groups: 21 patients treated with GLP-1 RAs (alone or in combination with other agents) and 14 patients treated with non-GLP-1 RA glucose-lowering medications. Ocular surface parameters-including Schirmer I test and tear breakup time (TBUT)-were assessed and compared between groups.

Patients receiving GLP-1 RAs demonstrated significantly higher Schirmer I test values (median 15 mm, range 1-33) compared to non-GLP-1 RA users (median 7.5 mm, range 0-40; p = 0.016). TBUT was also significantly longer in the GLP-1 RA group (median 10 sec, range 6.7-17) versus controls (median 5.85 sec, range 1-11; p < 0.01). A subgroup analysis revealed significant differences in tear production across patients treated with GLP-1 RAs alone, SGLT2 inhibitors alone, or both (p = 0.016).

GLP-1 receptor agonist therapy is associated with improved tear production and tear film stability in patients with type 2 diabetes, suggesting a potential protective effect on the ocular surface. These findings highlight an emerging link between antidiabetic therapies and ocular surface health. Prospective, larger-scale studies are warranted to validate these preliminary results and investigate underlying mechanisms.