Abstract: Methods and apparatus are provided for the noninvasive detection and measurement of macular pigments such as carotenoids in macular tissue. In one technique, lipoftiscin autofluorescence spectroscopy is utilized for macular pigment measurements. In autofluorescence spectroscopy, the emission of lipoftiscin is excited at two wavelengths: one wavelength that overlaps both the macular pigment and lipofuscin absorption and another wavelength that lies outside the macular pigment absorption range but that still excites the lipofuscin emission. The macular pigment absorption is then derived from the different lipoftiscin emission intensities in the macula and peripheral retina. In another technique, both autofluorescence spectroscopy, as described above, and resonance Raman spectroscopy are used to identify and quantify the presence of carotenoids in macular tissue. In using resonance Raman spectroscopy, laser light is directed onto the eye tissue and the scattered light is then spectrally filtered and detected.

Abstract: Methods of supplementing a growth medium with means for enhancing the production of a carotenoid in a bacterium are disclosed. In various embodiments, the growth medium is supplemented with a salt or a TCA cycle intermediate to enhance the production of the carotenoid. Bacterial cell cultures including the means for enhancing the production of the carotenoid in the bacterium are also disclosed.