[Physical principles of optical biopsy].

The purpose of this presentation is to explain the physical principles underlying the three main methods used to obtain images of living tissues at the cellular scale. In confocal microscopy, the tissue of interest is illuminated and scanned through a confocal aperture; a lateral resolution close to 1 microm can be obtained with high numerical aperture. Multiphoton microscopy uses a high-power short-pulse laser with instantaneous irradiance sufficient to excite fluorescence in a very small focal volume.

Genetic variants in BCMO1 and CD36 are associated with plasma lutein concentrations and macular pigment optical density in humans.

Unlabelled: Lutein is recovered at high concentration in the human macula lutea. Recent studies suggest that this micronutrient might be implicated in prevention of age-related macular degeneration.

Objective: to identify genes which affect blood and retina lutein concentrations among candidate genes (intestinal sterol transporters and carotenoid oxygenases).

Macular pigment density assessed by directional fundus reflectance.

Light radiated from foveal photoreceptors was analyzed in the eye's pupil at 470 nm and 532 nm. The reflectance of the inner limiting membrane was then measured at 6 deg from the fovea for the same wavelengths, allowing us to determine the macular pigment (MP) density D(dir) using the directional reflectance technique. In addition we measured the MP density D(nd) using the nondirectional reflectance technique (26 subjects).

Alignment parameters of foveal cones.

In the fovea we measured the orientation and directional characteristics of photoreceptors with an optical technique in a group of 29 subjects. At 6 deg eccentricity, we determined the direction of the normal to the inner limiting membrane (ILM) by analyzing light reflected specularly by the ILM. We found a strong correlation between the orientation of photoreceptor axes and the direction of the normal to the ILM.

Short-term supplementation with lutein affects biomarkers of lutein status similarly in young and elderly subjects.

There is evidence that lutein may protect against age-related macular degeneration, cataract, cancers and cardiovascular diseases, but no data have been published on the effect of age on lutein status. The purpose of this work was to determine whether there are major differences in the status of this carotenoid between young and elderly subjects. Initial lutein status and the effect of a 5-week lutein supplementation (9 mg/d) on the most common markers of lutein status were compared in 12 young (26.