Abstract: A method and device for accurately determining oxygen saturation of hemoglobin by the measurement of the optical density of a sample, such as a blood vessel, in response to illumination by light having at least three wavelengths (?i, ?2, ?3, . . . ) within a range of about 460 nm to about 523 nm. The hematocrit of a sample may be determined from optical density measurements at the three or more wavelengths in conjunction with a known path length. The device may be an intravenous or intra-arterial fiber optic catheter used to deliver the interrogating light signal to the blood and to detect the reflected signal. A method and device of determining the thickness of the retinal well using spectroscopic information are also disclosed.

Abstract: A method and apparatus are provided for accurately measuring the blood oxygen saturation with a retinal vessel. The apparatus includes an optical source for illuminating the retinal vessel with optical signals. The apparatus also includes a filter, such as an aperture, disposed within the path of the optical signals returning from the eye. The filter preferentially passes single pass optical signals that have diffused through the retinal layer and/or the choroidal layer of the eye while traversing the retinal vessel only once, while blocking or otherwise redirecting the other optical signals. The apparatus also includes a detector for separately detecting at least the single pass optical signals and, in some instances, the other optical signals as well. The apparatus can also include a processing element for determining the blood oxygen saturation in the retinal vessel based upon the optical signals that have been detected.

Abstract: Methods, apparatus and computer program products are provided for more accurately determining the percent transmittance of a vessel, such as a retinal vessel, at each of a number of different wavelengths and, in turn, for more accurately determining the blood oxygen saturation within the vessel. The blood oxygen saturation is determined based upon a plurality of images of the vessel obtained with illumination of different wavelengths. Background images are generated based upon respective images of the vessel in order to approximate the tissue bed underlying the vessel, such as the background fundus underlying the retinal vessel. Thereafter, a plurality of transmittance images are determined based upon respective pairs of the background images and the images of the vessel, such as by dividing the image of the vessel by the respective background image. Based upon a plurality of transmittance images, the blood oxygen saturation in the vessel may be determined.

Abstract: Methods, apparatus and computer program products are provided for more accurately determining the percent transmittance of a vessel, such as a retinal vessel, at each of a number of different wavelengths and, in turn, for more accurately determining the blood oxygen saturation within the vessel. The blood oxygen saturation is determined based upon a plurality of images of the vessel obtained with illumination of different wavelengths. Background images are generated based upon respective images of the vessel in order to approximate the tissue bed underlying the vessel, such as the background fundus underlying the retinal vessel. Thereafter, a plurality of transmittance images are determined based upon respective pairs of the background images and the images of the vessel, such as by dividing the image of the vessel by the respective background image. Based upon a plurality of transmittance images, the blood oxygen saturation in the vessel may be determined.

Abstract: A method and apparatus are provided for accurately measuring the blood oxygen saturation with a retinal vessel. The apparatus includes an optical source for illuminating the retinal vessel with optical signals. The apparatus also includes a filter, such as an aperture, disposed within the path of the optical signals returning from the eye. The filter preferentially passes single pass optical signals that have diffused through the retinal layer and/or the choroidal layer of the eye while traversing the retinal vessel only once, while blocking or otherwise redirecting the other optical signals. The apparatus also includes a detector for separately detecting at least the single pass optical signals and, in some instances, the other optical signals as well. The apparatus can also include a processing element for determining the blood oxygen saturation in the retinal vessel based upon the optical signals that have been detected.

Abstract: An improved optical scanning spectroscopic method and apparatus is provided that alternately scans the posterior portion of an eye with laser signals emitted by different ones of a plurality of lasers such that a data frame can be constructed that includes interlaced portions formed from signals returning from the posterior portion of the eye in response to illumination by laser signals emitted by different ones of the plurality of lasers. As such, the same data frame includes data attributable to the reflection of laser signals from each of the plurality of lasers even though the subject's eye is not subjected to simultaneous illumination by each of the lasers, thereby protecting the subject's eye.

Abstract: The method and apparatus for measuring the transmittance of blood within a retinal vessel detects the intensity of light reflected from illuminated portions of an eye, including the retinal vessel and background fundus, and adjusts the corresponding intensity signals to compensate for reflections from the retinal vessel. In particular, the transmittance measuring method and apparatus constructs an intensity profile function based upon the intensity signals. As a result, the intensity profile function approximates the intensity of light transmitted through the retinal vessel as a function of retinal vessel position. During the construction of the intensity profile function, the transmittance measuring method and apparatus can compensate for at least some of the reflections of light from the retinal vessel which occurred prior to propagation of the light through the retinal vessel, thereby increasing the accuracy with which the transmittance of blood within a retinal vessel is measured.

Abstract: A reflector for modifying the light intensity distribution patterns of a cylindrical light source has a first reflecting surface formed to provide a desired light intensity distribution pattern in the vertical plane and at least one other reflecting surface extending from one end of the first reflecting surface and which is oriented and formed to provide a second desired light intensity distribution pattern in the horizontal plane.