1. An image processing apparatus comprising: a detection unit configured to detect layers on the retina based on tomographic images of the retina; an acquisition unit configured to acquire a region having a larger curvature of the boundary surface between the retina and the corpus vitreum than a threshold value; and a determination unit configured to determine an optic disc of the retina based on the optical disc including a region where a specific layer is not detected by the detection unit and the region acquired by the acquisition unit.