A control apparatus comprising tomographic-image obtaining means for obtaining a first tomographic image of a subject's eye based on combined light obtained by combining return light returned from the subject's eye irradiated with measurement light with reference light corresponding to the measurement light, and for obtaining a second tomographic image of the subject's eye in response to an instruction to obtain the second tomographic image and display control means for causing display means to display the first tomographic image and a first display form indicating information about image quality of the first tomographic image, and then for causing the display means to display the second tomographic image obtained in response to the instruction, a second display form indicating information about image quality of the second tomographic image, and a display form for selecting re-obtainment of the second tomographic image of the subject's eye.
