An image processing apparatus which processes a tomogram of an eye region, comprising: layer acquisition means arranged to acquire a predetermined layer boundary from the tomogram; state determination means arranged to determine whether a layer included in the tomogram is abnormal or normal based on the layer boundary acquired by the layer acquisition means; algorithm determination means arranged to determine an algorithm for acquiring, based on whether the layer included in the tomogram is abnormal or not as determined by the state determination means, diagnosis information data as information to be used for diagnosis of the eye region from the tomogram; and data acquisition means arranged to acquire the diagnosis information data from the tomogram based on the algorithm determined by said algorithm determination means, normal structure estimation means arranged to estimate a normal structure of a pigmented retinal layer; wherein the algorithm determination means is arranged to determine an algorithm for acquiring a difference between the pigmented retinal layer boundary of a pigmented retinal layer subject to macular degeneration and the normal structure estimated by the normal structure estimation means, when the state determination means determined that the pigmented retinal layer is abnormal; and the data acquisition means is arranged to acquire the difference between the pigmented retinal layer boundary and the normal structure estimated by the normal structure estimation means, the state determination means is arranged to determine whether the state of the pigmented retinal layer boundary is normal or abnormal, by using at least one piece of information of information indicating statistics concerning an extreme value of a point sequence constituting the pigmented retinal layer boundary, the number of inflection points, a curvature, and an angle, and the data acquisition means, in a case where the state of the pigmented retinal layer boundary is normal is arranged to determine and display the thickness of the nerve fiber layer. layer acquisition means arranged to acquire a predetermined layer boundary from the tomogram; state determination means arranged to determine whether a layer included in the tomogram is abnormal or normal based on the layer boundary acquired by the layer acquisition means; algorithm determination means arranged to determine an algorithm for acquiring, based on whether the layer included in the tomogram is abnormal or not as determined by the state determination means, diagnosis information data as information to be used for diagnosis of the eye region from the tomogram; and data acquisition means arranged to acquire the diagnosis information data from the tomogram based on the algorithm determined by said algorithm determination means, normal structure estimation means arranged to estimate a normal structure of a pigmented retinal layer; wherein the algorithm determination means is arranged to determine an algorithm for acquiring a difference between the pigmented retinal layer boundary of a pigmented retinal layer subject to macular degeneration and the normal structure estimated by the normal structure estimation means, when the state determination means determined that the pigmented retinal layer is abnormal; and the data acquisition means is arranged to acquire the difference between the pigmented retinal layer boundary and the normal structure estimated by the normal structure estimation means, the state determination means is arranged to determine whether the state of the pigmented retinal layer boundary is normal or abnormal, by using at least one piece of information of information indicating statistics concerning an extreme value of a point sequence constituting the pigmented retinal layer boundary, the number of inflection points, a curvature, and an angle, and the data acquisition means, in a case where the state of the pigmented retinal layer boundary is normal is arranged to determine and display the thickness of the nerve fiber layer.