Ophthalmology

The goals of the project included ocular imaging pilot research in primates using hyperspectral imaging, design of a prototype one dimensional spectral camera for human recordings and testing of the device in normal subjects. Primate imaging was completed in 2004 with success. Analysis of imagery from the peripapillary retina and optic nerve head showed distinct spectral differences among the two vessel types, artery and vein, and the backgrounds presented by the nerve head and retina.

The spectral features were confirmed in the one-dimensional spatial-spectral images obtained with the prototype sensor in human subjects. The advantage of the one-dimensional image format is that only a single image is needed to discern both spatial and spectral information.

Our results showed that retinal arteries and veins were detected over background in the 550 - 580 nm spectral range, and were separately identifiable from each other in the 600 - 610 nm spectral range. Curve fits applied to the full 500 - 600 spectral range of hemoglobin absorption, or over selected ranges set between isosbestic wavelengths, were able to quantitate the blood oxygen saturation.

The goals of the project were thus completed. A fully portable instrument is possible, based on these findings that could be worn by the crew in spaceflight. Such an instrument would employ a simpler and lighter optical analyzer such as the nondeviating prism, with illumination of the ocular fundus from ring light employing white LEDs.

For more information about this or any other past research, contact us.