Laser raman spectroscopy of the lens in situ, measured in an anesthetized rabbit

We have obtained the first Raman spectrum from the lens of a live animal. A laser beam (514.5 nm; 15 mW) was directed into the eye of an anesthetized rabbit at 60 degrees from the visual axis and Raman emission was collected at 90 degrees from the incident beam. The power density at the retina was estimated at 0.5 W/cm2. The entire scattering column in the lens can be imaged on the entrance slit of a spectrometer with so little distortion that Raman "optical dissection" analysis (Askren, Yu and Kuck (1979) Exp. Eye Res. 29, 647) can be performed on the in situ lens. The advantages of multichannel detectors over photomultiplier tubes with respect to in situ measurements are discussed.