A control apparatus includes a display control unit configured to cause a display unit to display an image of an anterior segment of a subject's eye captured by an imaging unit, and a control unit configured to output, based on an operation signal output from a mouse according to an operation on the mouse when an index indicating an arbitrary position on the display unit is located on the image of the anterior segment, a control signal indicating a change amount in an optical axis direction of the imaging unit of a focal position of the image of the anterior segment relative to the imaging unit.
