Polarization enhanced wide-field imaging for noninvasive rapid evaluation of dermal structures

Changes in the morphology of dermal collagen may indicate aging or pathological processes. At present, there is no technology for in vivo real-time assessment of collagen structures. The goal of this work was to introduce polarization optical imaging for noninvasive quantitative evaluation of dermal collagen. To validate the imaging device and method, cross-polarized 440 nm images were acquired noninvasively from facial skin of seventeen subjects. Collagen content and intensity histogram were computed from the optical images. Quantitative results showed a decrease in the collagen content with increasing age of the subjects. Analysis of the collagen image histogram parameters demonstrated decreasing mean pixel value and increasing full width at half maximum (FWHM) with increasing age. In the second study, the polarization enhanced wide-field imaging device was used to monitor the early effects of the non-ablative fractional treatment (NAFT). Eight subjects (skin types I to III) used a commercially available NAFT device (wavelength 1410 nm, energy per pulse up to 15 mJ) to treat peri-orbital wrinkles for a period of two weeks. In each session, subjects applied a pre-treatment gel to the peri-orbital areas and then used the device, delivering 8 to 10 applications to each side of the face without overlap. Quantitative assessment of collagen images revealed statistically significant (p < 0.05) improvement of collagen content at a time point of two weeks. Seven out of eight subjects showed varying degree of improvement. Subjects in their early 40s showed the best improvement in comparison to younger and older age groups.;Polarization enhanced wide-field imaging has shown promise for rapid noninvasive in vivo evaluation of human dermis. The imaging device and method are of interests to investigators and clinicians involved with biomedical optics and monitoring dermal structural changes.