Tranexamic acid exerts various effects on living bodies; however, its effects on asthenopia remain unknown. In this study, an asthenopia-like model was developed and used to investigate the effects of tranexamic acid on asthenopia. Mice were placed in special cages constructed for the test, and continuous irradiation with blue light was applied for 20 days. The tranexamic acid-treated group was orally administered tranexamic acid daily during the test period. Motor activity was measured for 10 days after irradiation, and reactive oxygen species (ROS), plasmin, and transforming growth factor (TGF)-β levels in the ciliary muscle of the mice were measured on the last day. Blue light irradiation induced asthenopia and increased ROS, plasmin, and TGF-β levels. In contrast, tranexamic acid administration improved asthenopia and significantly decreased plasmin and TGF-β levels compared to blue light irradiation alone; however, ROS levels remained unchanged. The study results indicate that blue light irradiation induces asthenopia by activating the ROS/plasmin/TGF-β pathways and that tranexamic acid improves asthenopia by suppressing plasmin production.