Purpose: To evaluate the effect of tafluprost on the central corneal thickness (CCT) in patients with primary open-angle glaucoma (POAG). Methods: This was a prospective study and included 100 eyes of 54 patients with POAG. All patients received tafluprost 0.0015% (Saflutan (R)) once daily in one or both eyes. CCT was measured by using noncontact pachymetry prior to the treatment and after 6 and 12 months. Results: Mean CCT of all treated eyes (n = 100) was 547.79 +/- 29.48 mu m at baseline, 535.61 +/- 26.54 mu m after 6 months and 533.55 +/- 26.45 mu m after 12 months (Student's t test, p < 0.0001). Ninety-three percent of all treated eyes showed a decrease of CCT. CCTreduction was more significant within the first six months of the treatment period (Student's t test, p < 0.0001). After 12 months, a CCT reduction > 25 mu m occurred in 5% of all treated eyes. There was a significant positive correlation between the magnitude of corneal thinning and the initial CCT (Pearson, r = 0.49, p < 0.0001) but not between the magnitude of corneal thinning and intraocular pressure (IOP) reduction (Pearson, r = 0.145, p = 0.15). Discussion: Long-term use of tafluprost may decrease the CCT in patients with POAG. Consequently, clinicians must be aware of prolongated CCT variations that may arise throughout the follow-up period for proper IOP targeting and management.