Ophthalmologic apparatus

An ophthalmologic apparatus comprising:

• a light source;
• an optical measurement system configured to radiate first light from the light source to inside an eye to be examined and guides first reflected light from the eye;
• an optical reference system configured to radiate second light from the light source to a reference surface and guides second reflected light from the reference surface;
• a photo detector configured to detect interfering light between the first reflected light from the optical measurement system and the second reflected light from the optical reference system;
• and
• a processor configured to determine a first position of a first measuring portion inside the eye based on the detected interfering light,
• wherein the optical measurement system comprises an incident angle changing member configured to change an incident angle of the first light radiated to the eye within a predetermined angular range relative to an axis of vision of the eye,
• the incident angle changing member is configured to scan the incident angle within the predetermined angular range during a measurement,
• the photo detector is configured to detect interfering light of each scan angle and output an interference signal of each scan angle to the processor,
• the interference signal of each scan angle includes a first signal component, the first signal component being created by the second reflected light and reflected light from the first position of the first measuring portion, and
• the processor is configured to determine the first position of the first measuring portion based on only the first signal component of the interference signal with respect to a first angular range with increased intensity of the interference signal which is higher than a first predetermined intensity.