To evaluate automatic peripapillary choroidal thickness (PPCT) measurements in a wide area around the optic disc and various established zones in primary open-angle glaucoma (POAG) patients and age- and sex-matched healthy controls using a new swept-source optical coherence tomography (SS-OCT) device. Single center cross-sectional observational study. A total of 135 POAG patients and 86 healthy subjects were consecutively enrolled. An optic disc 6.0 x 6.0 mm three-dimensional scan OD was obtained using the SS-OCT Triton. A 26 x 26 cube-grid centered in the optic disc was generated to automatically measure choroidal thickness. Seven choroidal zones were established (superior temporal, central, and nasal; inferior temporal, central, and nasal, and the optic nerve head) and compared between healthy controls and POAG patients. PPCT was significantly thinner in the central superior, nasal superior, and nasal inferior zones of the POAG subjects. Choroidal thickness in the central superior zone was 124.61 +/- 54.95 A mu m in POAG group vs 156.17 +/- 80.89 A mu m in healthy controls (p = 0.029); in the nasal superior zone, 133.84 +/- 58.89 A mu m in the POAG group vs 168.34 +/- 73.45 A mu m in healthy controls (p = 0.012); and in the nasal inferior zone, 113.45 +/- 49.93 A mu m in the POAG group vs 137.47 +/- 65.96 A mu m in healthy controls (p = 0.049). Compared with healthy subjects, glaucoma patients present with peripapillary choroidal thinning, especially in the central superior, nasal superior, and nasal inferior zones. The new SS-OCT could be a useful tool to evaluate choroidal thinning, and it could be an additional support to facilitate glaucoma diagnosis.