Glaucoma is the second leading cause of blindness worldwide. Literature shows increasing evidence that dysfunction of ocular microcirculation in the optic nerve influences the progression of glaucoma. Laser speckle flowgraphy (LSFG) represents a non-invasive method to quantify ocular perfusion also at the ONH. LSFG enables noninvasive quantification of microcirculation of the optic disc in Japanese glaucoma patients