📓 This book presents a series of studies on the development of non-contact lens based optical probe designs and data analysis methods for depth sensitive optical measurements, particularly Raman and fluorescence measurements, in skin pigmentary disorders. Several depth-sensitive optical probes and data processing algorithms are developed to extract layer-specific information from turbid media, which is clinically useful for the diagnosis and treatment evaluation of skin pigmentary disorders. Further improvement of these techniques would help advance the use of optical spectroscopy in clinical settings.