Patent ID: 8414125

Claim:
An apparatus for measuring an ocular axial length, the apparatus comprising: an interfering optical system that includes an emitting optical system including a light source configured to emit light, and a beam splitter for splitting the light emitted from the light source into first split light and second split light, wherein the emitting optical system is configured to project at least one of the first split light and the second split light toward an examinee's eye, a light receiving optical system configured to receive interference light obtained by an interference of the first split light and the second split light reflected at the examinee's eye, and output an interference signal, and an optical member configured to adjust an optical path difference between the first split light and the second split light and disposed on at least one of an optical path of the emitting optical system or an optical path of the light receiving optical system, and a driving part configured to move the optical member; a mode switching unit configured to issue a mode switching signal for switching a measurement mode between at least two measurement modes including a first measurement mode for measuring the ocular axial length while moving the optical member at a first scanning rate, and a second measurement mode for measuring the ocular axial length while moving the optical member at a second scanning rate slower than the first scanning rate; and a calculation and control unit configured to change a scanning rate of the optical member based on the mode switching signal issued by the mode switching unit, control an operation of the driving part to move the optical member at the scanning rate corresponding to the measurement mode switched by the mode switching unit, and measure the ocular axial length based on the interference signal output from the light receiving optical system.