1. An image processing apparatus comprising: an image obtaining unit configured to obtain a three-dimensional tomographic image of an eye in a depth direction; a detection unit configured to detect a lamina cribrosa from the three-dimensional tomographic image; an analyzing unit configured to obtain, by analyzing a shape of the detected lamina cribrosa, an analysis parameter value which includes at least one of a curvature value and a value obtained by using a Bruch membrane opening of the detected lamina cribrosa; a generating unit configured to generate a two-dimensional map showing the obtained analysis parameter value; and a display control unit configured to control a display unit to display the generated two-dimensional map.