Kowa Company Limited

Masaharu Mizuochi

Kazunori Matsumura

Toshiaki Nakagawa

Tatsuya Fujii

Takayoshi Suzuki

Takuya Hara

Naoki Kobayashi

Yoshihiro Kakutani

The tomographic image capturing device of the present invention includes a tomographic image capturing means that scans measurement light on a subject's eye fundus (E) to capture tomographic images of the subject's eye fundus and an image processing means that compresses a picture of the captured tomographic images in a scan direction to generate a new tomographic picture. The tomographic image capturing means performs scan at a second scan pitch (P) narrower than a first scan pitch (P) to capture the tomographic images of the subject's eye fundus. The image processing means compresses the picture (B) of the tomographic images captured at the second scan pitch (P) in the scan direction to generate the new tomographic picture (B). The measurement width in the scan direction of the new tomographic picture (B) is a width of a picture corresponding to a measurement width in the scan direction of a tomographic picture (Bn (n=1 to 10)) obtained by scan at the first scan pitch (P).

Tomographic image capturing device

A three-dimensional tomographic image (B) is formed which is composed of a plurality of two-dimensional tomographic images obtained by scanning an ocular fundus. A contour of a certain 2D region (M, M, M, M) in the tomographic image is determined for each tomographic image, and the volume of a certain 3D region is calculated through correcting each area of the certain 2D region defined by the determined contour or its accumulated value using an image correction coefficient in accordance with the diopter of the subject's eye. Even for subjects' eyes of different diopters, the influence of the diopter correction is eliminated and a quantitative comparison of subjects' eyes of different diopters is possible.

Volume measuring device, volume measuring method, and volume measuring program for three-dimensional tomographic image

An ocular light stimulus apparatus provides the ocular fundus of an examinee's eye under examination with observation light to observe the ocular fundus and provides localized background light and stimulus light to a retina of the ocular fundus to perform biological examination through use of a bioelectrical signal from the retina. The ocular light stimulus apparatus has a ring slit and a photographic stop. Each of the ring slit and the photographic stop is disposed in a position substantially conjugate with the anterior ocular segment of the eye to be examined so that the ocular fundus of the eye is irradiated with the ocular fundus observation light via the ring slit and is irradiated with the stimulus light and the background light via the photographic stop.

Ocular light stimulus apparatus

A timer function hold mode in which the timer continues the timing function is set in a mydriatic fluorescence mode by operating a timer switch for at least a fixed time, or by simultaneously operating a fluorescence filter switch and the timer switch. If the timer function hold mode is set in the mydriatic fluorescence mode, then the timing of the timer is continued even after the photography mode switches to another photography mode e.g. non-mydriatic or mydriatic color mode. When, on the other hand, the timer function hold mode is not set in the mydriatic fluorescence mode, the timer is caused to be stopped or reset when the mode is switched to the non-mydriatic or mydriatic color mode.

Ophthalmic photographic apparatus

Stimulus light is projected from a stimulus light source onto an ocular fundus of an eye under examination to locally stimulate the retina in order to perform a biological examination. During a biological examination, first background light is projected from an illumination light source via an objective lens, and second background light is projected from a light source from the periphery of the objective lens onto the ocular fundus. During alignment prior to a biological examination, the first background light is turned off and the second background light is projected onto the ocular fundus. During observation of the ocular fundus, the first background light projected onto the fundus is blocked, so that fundus observation or eye fixation is not disturbed by the background light. This enables accurate alignment to be carried out. Since the examinee's eye is irradiated with the second background light from the periphery of the objective lens in preparation for a biological examination, the examinee's eye can sufficiently adapt to the light during a biological examination, ensuring a reliable biological examination.

A stimulus light from a stimulus light source is projected to the retina of an ocular fundus under examination to stimulate the retina in localized fashion to generate a bioelectric signal from the retina. The stimulus light source is mounted on a movable block, and an operating lever is used to move the stimulus light source to change the stimulus light on the retina. The size of the stimulus light can also be varied using a panel having a plurality of openings with different diameters for allowing the stimulus light to pass through. This assures a reliable local ERG examination because the bioelectrical signal can be produced in a wider area of the retina. The operating lever is further fixed by inserting a cap to keep the projected stimulus light unchanged. This allows the burden on the examiner to be reduced remarkably, assuring a reliable local ERG examination.

An ophthalmic photography apparatus is provided in which focus and alignment can be adjusted over the whole period of infrared light-excited fluorescence photography. During alignment and focus adjustments, the brightness of index light sources used for such adjustments is increased. When the shutter is operated, the brightness of the index light sources is decreased, dimming the indexes. When the automatic gain control of the imaging device functions in the later phase of the photography, the brightness of the indexes is gradually increased. In the first part of the photography period, the indexes are dimmed to prevent the images thereof from showing up on the recording images, and are brightened in the later stages to make the indexes easier to see.

Ophthalmic photography apparatus

An ophthalmic photographic apparatus is provided that is readily able to capture dynamic and still eye fundus images by infrared light-excited fluorescence. A CCD device that is sensitive to infrared light is used to capture images of the eye fundus as dynamic and still images. When the shutter button is pressed, infrared light-excited fluorescence images are obtained as still images and stored in a recording unit. The infrared light-excited fluorescence image of the eye fundus is captured as a still image with or without a flash from a strobe light source. Such an arrangement makes it possible to capture still images even when dynamic images are being recorded.

An ophthalmic photographic apparatus includes an illumination optical system for illuminating an eye fundus and a photographing optical system for photographing an image of the illuminated eye fundus. The ophthalmic photographic apparatus includes a first aperture stop, a second aperture stop having an outside diameter that is smaller than that of the first aperture stop, a third aperture stop that transmits more light than the first aperture stop, and means for selectively inserting the first to third aperture stops into the optical path of the illumination optical system. The ophthalmic photographic apparatus does not have a complicated structure, but can be readily used in the various photographing modes.

An ophthalmic imaging apparatus has a first storage means that stores image data acquired from an eye being examined. The apparatus further has a second storage means that is slower than the first storage means and is used to hold image data transferred from the first storage means. It is determined whether or not the imaging of the eye is performed in a specific continuous imaging mode. If it is determined that the system is in the continuous imaging mode, the transfer of image data from the first to second storage means is held back until the continuous imaging mode terminates. Otherwise the transfer of image data is carried out for each imaging operation.

Ophthalmic imaging apparatus

When fluorescent photography is initiated, a mode switching signal is sent to the image processing section to change the image processing mode to monochrome processing. At the same time, a timer is started that indicates the time elapsed since the fluorescent agent was administered. While the timer is on, fundus images acquired are converted to monochrome images by the image processing section and displayed on a monitor and stored in an image storage device. When the system enters fluorescent photography mode, images are converted to monochrome images automatically. This eliminates the need for a mode switching operation using a mode conversion button or the like to switch from color mode to monochrome mode.

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Hamamatsu, Japan

Masaharu Mizuochi