This instrumentation assesses the level of the carotenoid pigments, lutein and zeaxanthin, present in the human macula. These pigments protect against age-related macula degeneration, the leading cause of blindness in the elderly. Resonance Raman spectroscopy is a non-invasive methodology that allows quantification of these macular pigments in the retina. The Resonance Raman Spectrometer, which was developed at the University of Utah, requires the subject to align an illuminated fiber optic array, which simulates the argon ion excitation laser beam, with a representation of the detector optical pupil prior to initiating the laser pulse that produces the Raman backscattered signal. This alignment is a simple matter with patients who possess good visual acuity, but degeneration of the macular makes the alignment a difficult problem. To overcome this problem, the instrument was modified to provide a video presentation of the subject?s eye centered on the cornea. A low-level helium-neon laser was introduced into the instrument?s optical path co-linear with the optical axis of the Raman excitation and emission pathways. The video camera captures the scattered and reflected laser beam from the front surface of the cornea. The physician adjusts the position of the subject?s eye until the laser beam is centered on the cornea. This is accomplished by orienting to fiducial marks and by the increase in reflected intensity as the front surface of the cornea becomes perpendicular to the incident alignment laser beam.
