Imaging spectrometry in ophthalmology--principle and applications in microcirculation and in investigation of pigments.
Imaging spectrometry is a new technique that permits simultaneous measurements of reflectance spectra at different locations along a line. Results are three-dimensional images, whose coordinates are location, wavelength, and reflectance. A conventional fundus camera is adapted to a spectrograph and an intensified charge coupled device (CCD) matrix detector system. The spectral resolution of this spectrometer is lower than 2 nm within a spectral range between 395 and 710 nm. The local resolution is lower than 23 microns along a line of 1.5 mm. From an imaging spectrum, the extinction spectrum of blood in vessels can be calculated. Also, in case of a noisy extinction spectrum of blood, its approximation by a model function results in calibration-free measurement of the oxygen saturation. Considering the radiation transport in single fundus layers, the local distribution of the concentration-thickness product of xanthophyll, melanin, and choroidal blood can be calculated.
Schweitzer
D
D
Department of Ophthalmology, University of Jena, Germany.
Hammer
M
M
Scibor
M
M
D000818:Animals; D003952:Diagnostic Imaging / Q000295:instrumentation / Q000379:methods*; D005123:Eye / Q000098:blood supply*; D005584:Fovea Centralis; D014975:Lutein / Q000378:metabolism; D008543:Melanins / Q000378:metabolism; D008833:Microcirculation; D009885:Ophthalmology; D010100:Oxygen / Q000378:metabolism; D012171:Retinal Vessels / Q000378:metabolism; D013053:Spectrophotometry; D013552:Swine
D008543:Melanins; D010100:Oxygen; D014975:Lutein