The effects of mirabegron and anticholinergic treatment on anterior segment and pupillary responses in overactive bladder syndrome

To evaluate the effect of tolterodine and mirabegron on anterior chamber parameters and static pupillometry measurements in overactive bladder (OAB) patients and to compare these results with those of healthy controls. This study included 35 patients with OAB who were planned to be treated with tolterodine, 35 patients with OAB who were planned to be treated with mirabegron, and 35 healthy control subjects. All the participants underwent full ophthalmic examination and scanning with Sirius topographer (CSO, Firenze, Italy) before and at 1 and 3 months in both the control and the mirabegron and anticholinergic groups after treatment. In addition, central corneal thickness (CCT), anterior chamber depth, angle, and volume were recorded. The mean intraocular pressure (IOP) increased significantly in the first month of treatment after mirabegron ( p = 0.034). Anterior chamber depth increased significantly in the mirabegron group at the third month of treatment compared to pretreatment ( p = 0.039). Higher mesopic and photopic pupil diameters were found at 1 and 3 months after tolterodine compared to baseline ( p < 0.05 for all). Higher scotopic pupil diameters were found at 1 month after mirabegron ( p = 0.002). No statistical differences were found between pretreatment and posttreatment static pupillometry and anterior chamber parameter measurements in the control group ( p > 0.05 for all). Our study demonstrated that both tolterodine and mirabegron affected pupil diameters under different light conditions. They also caused changes in anterior chamber parameters. However, given the modest magnitude of these changes and the dynamic nature of pupil diameter, caution should be exercised in the clinical interpretation of the results.