A stereoscopic tomographic image B composed of a plurality of two-dimensional tomographic images obtained by scanning the fundus is formed. For each tomographic image, the contour of the predetermined part M1, M2, M3, M4 in the tomographic image is determined, and the area of the predetermined part determined by the determined contour or its integrated value is an image corresponding to the diopter of the eye to be examined. The volume of the predetermined part is calculated by correcting with the correction coefficient. Even if the subject's eyes have different diopters, the effect of diopter correction is eliminated, and the subject's eyes having different diopters can be quantitatively compared.眼底をスキャンすることにより得られる複数の２次元の断層画像からなる立体断層画像Ｂを形成する。各断層画像毎に断層画像内の所定部位Ｍ１、Ｍ２、Ｍ３、Ｍ４の輪郭を決定し、その決定された輪郭で定まる所定部位の各面積あるいはその積算値を被検眼の視度に応じた画像補正係数で補正して所定部位の容積を演算する。異なる視度の被検眼であっても、視度補正の影響が排除され、異なる視度の被検眼同士の定量的な比較が可能となる。
