These results demonstrate the advantage of in vivo multiphoton microscopy over other noninvasive imaging methods, such as OCT or confocal microscopy, that lack specificity, as their contrast mechanism relies on spatial variations of refractive indices. Stratum corneum compactum and intracellular granular keratinocytes modifications cannot be studied with these imaging methods. Melanin visualization in confocal microscopy is based on its high reflectivity. However, melanin 3-D quantification from confocal images (which has not been performed to our knowledge) is not trivial since the cellular membranes also exhibit a reflection signal with intensity similar to the one created by melanin. Moreover, multiphoton microscopy offers additional modes of contrast, as discussed in the introduction section, and provides 3-D images with better resolution than in vivo confocal images acquired with commercial systems such as VivaScope® (Mavig, Munich, Germany): 400 nm experimental lateral resolution instead of 1.25 µm and 2 µm axial resolution instead of 5 µm. One disadvantage of multiphoton microscopy over confocal microscopy is the field of view, which is indeed quite small. However, a large area scanning (tiles of images) is only compatible with 2-D imaging of living samples like humans or 3-D imaging of fixed samples. As 3-D image acquisition with DermaInspect® takes about 9 min, a large area scanning (tile of -stacks of images) will require 36 min, and the effects of volunteer movements will degrade the quality of the images. Moreover, most of the in vivo studies performed with the DermaInspect® system deal with the same problem. The authors of these studies have been able, however, to demonstrate that such a reduced image field is enough to evidence modifications appearing during skin aging, etc.