Patent ID: 8851672
Filing Date: 2014-10-07
Classification: A61B

Abstract:
1. A fundus photographing apparatus, comprising: an illuminating optical system for illuminating a fundus of an examinee's eye; a focus target presenting unit for projecting a focus target for focusing to the fundus via an objective lens; a photographing element for photographing the fundus to obtain a fundus image and detect the focus target; a diaphragm arranged at a position substantially conjugate with a pupil of the examinee's eve with the objective lens interposed therebetween; a focusing lens that is moved along an optical axis to focus on the fundus; and a controlling device for moving the focusing lens along the optical axis based on a result of detection of the focus target by the photographing element with a position where a first distance from the diaphragm to the fundus is substantially equal to a second distance from an image of the diaphragm to the fundus image as a reference position of the focusing lens, wherein the reference position of the focusing lens is determined based on the following equation (1): wherein L is a distance from the diaphragm to the fundus image, f is a focus length of the focusing lens, g(D) is the first distance, and g a (D) is the second distance.