1. An image processing apparatus, which analyzes retina layers of an eye to be examined, comprising: a feature extraction unit configured to extract a feature amount, which represents an anatomical feature in the eye to be examined, from a projection image obtained from a tomogram of the retina layers and a fundus image of the eye to be examined; a determination unit configured to determine a type of the anatomical feature based on the feature amount; a layer structure detection unit configured to decide layers to be detected from the retina layers according to the determined type of the anatomical feature, and detecting structures of the decided layers in the tomogram; and a layer structure modifying unit configured to modify the structure of the layer included in a region having the anatomical feature of the structures of the layers detected by said layer structure detection unit.