Possibility of measuring lutein in the retina by confocal micro-imaging system

The microfabrication and measurements of organic materials have significant potential for industrial and medical applications. In particular, in the medical field, a non-invasive method of measuring the distribution of certain substances contained in organic materials has been strongly demanded. Introducing a fluorescence analysis system to a confocal system would be useful for the characterisation of materials while maintaining space resolution. In this study, we focused on age-related macular degeneration (AMD) as an example, and investigated the possibility of the visualisation of fluorescence spectra. We measured the fluorescence spectrum in photoreceptor cells that were separated from the macular of eyes obtained from an eye-bank, using a microslicer. Mixed spectra of lutein and zeaxanthin, which are not affected by other organisations of eye have been measured. We also evaluated the densities of lutein and zeaxanthin in photoreceptor cells from the spectrum. As a result, the mixing ratio of lutein to zeaxanthin was estimated to be 3.78:6.22. The results showed good agreement with the results of high-performance liquid chromatography (HPLC). The approach presented here can serve as a useful framework for measuring the densities of lutein and zeaxanthin in photoreceptor cells.