an acquiring unit including a refractometer and configured to acquire a dioptric power in a first region including a fovea of a subject's eye;

an Optical Coherence Tomography (OCT) unit including an OCT scanner and configured to acquire OCT data of a fundus of the subject's eye using optical coherence tomography;

processing circuitry configured as an analyzer configured to specify a shape of the fundus by analyzing the OCT data; and

the processing circuitry further configured as a calculator configured to calculate a dioptric power in a peripheral region of the first region of the fundus based on the dioptric power in the first region and the shape of the fundus,

wherein the shape of the fundus indicates a difference in depth position between a central region on the fundus and a peripheral region on the fundus.