Other

The University of Alabama

Thomas E Minnich

Russell A Chipman

Matthew H Smith

Kurt R Denninghoff

Lloyd W Hillman

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. In addition, the transmittance measuring method and apparatus can compensate for the finite point spread function of the light with which the eye is illuminated in order to further increase the resulting measurement accuracy.

Method and apparatus for accurately measuring the transmittance of blood

The method and apparatus for measuring the oxygen saturation of blood within a retinal vessel illuminates the retinal vessel with light having a combination of wavelengths selected to reduce the error in the measured blood oxygen saturation. The oxygen saturation measuring method and apparatus illuminates a retinal vessel with light having the selected combination of wavelengths. For example, the oxygen saturation measuring method and apparatus can illuminate the retinal vessel with light having a first wavelength between 460 nm and 503 nm, a second wavelength between 600 nm, and 770 nm and a third wavelength between 770 nm and 1000 nm. The oxygen saturation measuring method and apparatus then measures the transmittance of the blood within the retinal vessel in response to the illumination at each of the selected wavelengths. Based upon the respective transmittances of the blood within the retinal vessel that are measured at each of the selected wavelengths, the oxygen saturation measuring method and apparatus determines the oxygen saturation of the blood within the retinal vessel. By appropriately selecting the combination of wavelengths with which the retinal vessel is illuminated, the corresponding error in the measured blood oxygen saturation can be reduced.

Method and apparatus for measuring blood oxygen saturation within a

A combined eyelid retracting and eye flushing device that permits an operator to retract the upper eyelid of a patient for selective eye flushing or other treatment. The device comprises a frame with spaced apart ends. One end forms an integral handle and the other end defines a peripheral edge that forms an arcuate lip for securing the eyelid to the frame. A plurality of spaced apart orifices penetrate the lip to distribute suction along the entire edge surface. An integral flushing system attached to the frame near the lip comprises an irrigator with a hollow stem protruding outwardly from one side of the frame and an aspirator with a hollow stem protruding oppositely. The irrigation stem terminates in a nozzle that selectively sprays liquids upon the eye and the aspiration stem terminates in a receptive orifice that drains run-off liquids and entrained contaminants therefrom. The lip, irrigator and aspirator all connect to a plurality of channels housed inside the frame. The channels establish fluid flow communication through the frame from the lip, irrigator and aspirator to external vacuum suction, liquid and storage sources. When the device is deployed, an operator aligns the lip along the upper eyelashes and the aspirator stem adjacent the inner terminus of the palpebral fissure. The upper eyelid is then seated against the frame edge with vacuum suctioning through the lip. The upper eyelid is retracted as the frame rests upon the patient's forehead and superciliary arch.

Combined eyelid retractor and eye flushing device

A non-invasive eye oximeter which monitors the arteriovenous oxygen difference. The optic disc region of the ocular fundus is illuminated with three or more wavelengths of light focused in approximately the same area. One of the light sources serves as a tracking beam which, through reflectance spectrophotometry, is used to determine when the tracking light beam is focused upon the optic disc. The scanning light beams are primarily focused within the boundary of the tracking beam. The intensity of light reflected from retinal venules and arterioles is detected, and the arteriovenous oxygen difference is determined.

Method and apparatus for monitoring the arteriovenous oxygen difference

A non-invasive retinal scanning system which monitors internal blood loss. A portion of the ocular fundus is illuminated, in an annular fashion, with two wavelengths of light, one of which serves as a reference. Scanning the fundus circumferentially enables retinal venous blood to be detected, which corresponds to desaturated hemoglobin. The intensity of light reflected from the retinal vein is detected and converted to an electronic signal proportional to the value of oxygen saturation of venous hemoglobin, which becomes the value of interest. Thus, a decline in venous oxygen saturation over time correlates linearly with progressive internal bleeding.

Growing community of inventors

North Little Rock, AR, United States of America

Thomas E Minnich