According to an embodiment, an attachment is attached to a main body part and has multiple bright points arranged in a ring. A calculation part calculates a first astigmatic axis angle based on an image obtained by using an imaging optical system to photograph the patients eye while the multiple bright points are projected thereto. A storage stores the calculated first astigmatic axis angle and/or a second astigmatic axis angle measured before surgery. A mechanism changes the orientation of the main body part. A first input part inputs orientation information indicating the orientation of the main body part. A correction part corrects the first astigmatic axis angle and/or the second astigmatic axis angle based on the input orientation information. A display part displays the corrected first astigmatic axis angle and/or the corrected second astigmatic axis angle.
