PROBLEM TO BE SOLVED: To provide an eye axial length measuring device which can suitably measure the eye axial length of a cataract eye even if an inspector is not a skilled person.SOLUTION: The eye axial length measuring device has a measurement optical system which comprises: a light projection optical system for dividing light emitted from a light source and projecting a measuring beam to the bottom of an eye a light receiving optical system for leading light formed by synthesizing one light reflected at the bottom of the eye and the other light to a light receiving element and an optical member which is arranged in order to adjust a light passage difference. The eye axial length measuring device measures the eye axial length of the eye to be inspected on the basis of an interference signal outputted from the light receiving element, and also comprises: an imaging optical system which has an imaging element having an imaging face at a position almost conjugative with the anterior ocular segment of the eye to be inspected and images a diaphanoscopy image at the pupil of the eye to be inspected which is irradiated with eye-bottom reflection light and a light transmittance region specifying means which acquires the two-dimensional distribution of an opaque part in a prescribed region which is set so that an S/N ratio of the interference signal may satisfies a permission value by processing the diaphanoscopy image acquired by the imaging element, and specifies a light transmittance region in the prescribed region on the basis of the acquired two-dimensional distribution.COPYRIGHT: (C)2013,JPO&INPIT【課題】 白内障眼の眼軸長を好適に測定できる。【解決手段】 光源から出射された光を分割し、測定ビームを眼底に投光する投光光学系と、眼底で反射された一方の光と他方の光とが合成された光を受光素子に導く受光光学系と、光路差を調整するために配置された光学部材と、を備える測定光学系を有し、受光素子から出力される干渉信号に基づいて被検眼の眼軸長を測定する眼軸長測定装置において、被検眼前眼部と略共役な位置に撮像面を持つ撮像素子を有し、眼底反射光によって照明された被検眼瞳孔部における徹照像を撮像する撮像光学系と、撮像素子によって取得された徹照像を処理することにより、干渉信号のS/N比が許容値を満たすように設定された所定領域における混濁部の二次元分布を求め、求められた二次元分布に基づいて所定領域内における光透過領域を特定する光透過領域特定手段と、を備える。
