Ophthalmic image sensing apparatus

An ophthalmic image sensing apparatus, comprising:

• an illumination optical unit configured to illuminate an eye to be examined;
• a fundus image sensing optical unit configured to sense a fundus image of the eye to be examined;
• a sensing light source configured to illuminate the eye to be examined at the time of sensing the fundus image of the eye to be examined;
• a perforated mirror configured to branch optical paths of the illumination optical unit and the fundus image sensing optical unit;
• first and second relay lenses having focal points near an opening of the perforated mirror;
• a focus unit including a base, a slit chart dispose on the base, and a deflection prism disposed on the base at a position corresponding to a slit opening in the slit chart, wherein the focus unit is configured to determine whether or not a corresponding slit image is shifted from a fundus of the eye to be examined;
• a light shielding member arranged in a nearly focal position of the second relay lens;
• and
• a retreating unit configured to retreat the focus unit out of the optical axis of the illumination optical unit in a case that the fundus image sensing optical unit senses the fundus image,
• wherein the focus unit is positioned within the illumination optical unit and the slit opening in the slit chart is arranged on an optical axis of the illumination optical unit between the first and second relay lenses, and on an optical path between the sensing light source and the eye to be examined.

An ophthalmic image sensing method comprising:

• illuminating an eye to be examined with infrared light from an illumination optical unit;
• illuminating the eye to be examined with a focus index from a focus unit;
• and
• retreating the focus unit out of an optical axis of the illumination optical unit in a case where a fundus image of the eye to be examined is sensed,
• wherein the focus unit includes a base, a slit chart disposed on the base, and a deflection prism disposed on the base at a position corresponding to a slit opening in the slit chart, and
• wherein the slit opening is arranged on the optical axis of the illumination optical unit.

A non-transitory computer-readable medium storing a computer-executable program which, when executed by a computer, causes the computer to perform an ophthalmic image sensing method comprising:

• illuminating an eye to be examined with infrared light from an illumination optical unit;
• illuminating the eye to be examined with a focus index using a focus unit;
• and
• retreating the focus unit out of an optical axis of the illumination optical unit in a case where a fundus image of the eye to be examined is sensed,
• wherein the focus unit includes a base, a slit chart disposed on the base, and a deflection prism disposed on the base at a position corresponding to a slit opening in the slit chart, and
• wherein the slit opening is arranged on the optical axis of the illumination optical unit.

An ophthalmic apparatus comprising:

• a focus index illumination light source;
• an optical member provided on an optical path of an illumination optical system and configured to separate a beam from the focus index illumination light source in a plurality of different directions;
• and
• a control unit configured to retreat the optical member from the optical path of the illumination optical system in accordance with an image sensing signal for sensing an image of an eye to be examined,
• wherein the optical member includes a base, a slit chart disposed on the base, and a deflection prism disposed on the base at a position corresponding to a slit opening in the slit chart, and
• wherein the slit opening is arranged on the optical path of the illumination optical system.

An ophthalmic apparatus comprising:

• an focus index illumination light source;
• an optical member provided on an optical path of an illumination optical system and configured to separate a beam from the focus index illumination light source in a plurality of different directions;
• and
• a control unit configured to insert the optical member into the optical path of the illumination optical system, after sensing an image of an eye to be examined while the optical member is retreated from the optical path of the illumination optical system,
• wherein the optical member includes a base, a slit chart disposed on the base, and a deflection prism disposed on the base at a position corresponding to a slit opening in the slit chart, and
• wherein the slit opening is arranged on the optical path of the illumination optical system.