Purpose The aim of this study was to determine the macular changes using optical coherence tomography (OCT) and OCT-angiography (OCT-A) in eyes with high myopia. Determining the alterations in vascular structures can provide a clearer understanding of the pathophysiological mechanisms of this disease and help define new treatment options and preventive measures. Materials and methods Ninety-two patients with high myopia (axial length >= 26 mm) and 70 control cases without any known systemic or ocular diseases were enrolled in this prospective study. One eye of each patient was included in the statistical analyses. Results Retinal nerve fiber layer (RNFL) thickness and Early Treatment Diabetic Retinopathy Study (ETDRS) macula map values were lower in myopia compared with the controls. Both superior and inferior ganglion cell complex (GCC) thicknesses were significantly thinner in the high myopia compared with the controls (p < 0.001). Regarding the OCT-A findings, although superficial or deep foveal avascular zones (FAZ) did not significantly differ between the two groups, the density values of superficial and deep microvessels were significantly lower in the high myopia group compared with the control cases. Conclusions In patients with high myopia, with an increase in the axial length and a decrease in RNFL and GCC thicknesses, the vascular densities of the superficial and deep retina were reduced in the macular region.