Imaging lutein and zeaxanthin in the human retina with confocal resonance Raman microscopy

Abstract

Lutein and zeaxanthin are xanthophyll carotenoids that are highly concentrated in the human macula, where they protect the eye from oxidative damage and improve visual performance. Distinguishing lutein from zeaxanthin in images of the human retina in vivo or in donor eye tissues has been challenging because no available technology has been able to reliably differentiate between these two carotenoids, which differ only in the position of one C = C bond. Here, we report the differential distributions of lutein and zeaxanthin in human donor retinas mapped with confocal resonance Raman microscopy. Zeaxanthin is highly concentrated in the fovea, extending from the inner to the outer limiting membranes, with especially high concentrations in the outer plexiform layer, while lutein is much more diffuse at relatively lower concentration. Our results imply that zeaxanthin may play a more important role than lutein in human macular health and disease. Significance We have determined the spatial distribution of the macular pigment carotenoids lutein and zeaxanthin in the human retina using confocal resonance Raman microscopy and found that zeaxanthin is highly concentrated in the fovea, while lutein is more diffusely spread across the macula at a relatively lower concentration. Our results imply that zeaxanthin may play a more important role than lutein in human macular health and disease, and they demonstrate the elegant ability of confocal resonance Raman imaging to probe the biochemistry and structure of the most important region of the human retina.