Raman Spectroscopy of Ocular Tissue - Emerging Raman Applications and Techniques in Biomedical and Pharmaceutical Fields - page 305

Fig. 12.16. Resonance Raman images of macular pigment distributions obtained
for the same subject with the Raman method ( a ) and with a fluorescence-based
imaging method ( b ); ( c ) comparison of integrated pigment densities obtained for
16 volunteer subjects with both imaging methods. A high correlation coecient of
R =0.89 is obtained for the correlation between both methods
integrated and compared. Using a best fit that is not forced through zero, a
high correlation coecient of R =0 . 89 was obtained between both methods.
The high correlation is remarkable in view of the completely different optical
beam paths and derivation methods used to calculate MP densities in both
methods.
Both methods can therefore quickly and objectively assess the compos-
ite lutein and zeaxanthin concentrations of MP using spatially averaged “in-
tegral” measurements or images that quantify and map the complete MP
distribution with high spatial resolution. Imaging reveals the existence of
spatially complex MP distribution patterns throughout the subject popula-
tion. The distributions vary strongly regarding widths, axial and rotational