**3.2. Lutein and visual functions**

#### *3.2.1. Blue light filter*

The peak value of MPs absorption is about 460 nm, which lies in the range of wave length of blue light (450–495 nm). Therefore, MPs can absorb 40–90% of incident high-energy, visible blue light depending on the concentration. The absorption offers protection from light-induced damages and reduction of light scatter in the retina. Junqhans A et al. [27] have investigated the efficacy of various carotenoids as the blue light filter using unilamellar liposomes with a fluorescent dye which was excitable by blue light. Different carotenoids were incorporated with the lipophilic membrane, and fluorescence intensity was lower in carotenoid-containing liposomes than in control group when exposed to blue light, indicating a role of carotenoids as the blue light filter [27]. It is noted that lutein is more efficient in filtering blue light than zeaxanthin and meso-zeaxanthin because of the orientation in the biological membranes [27, 28].
