This study introduces Structured Light Imaging Mesoscopy (SLIM), a novel non-contact optical method for detecting subsurface morphological tissue alterations. By leveraging the inherent sensitivity of spatial frequency domain (SFD) reflectance measurements, SLIM identifies specific wavelength-spatial frequency combinations that optimize the detection of scattering changes in the superficial dermis, a key area for various skin conditions. Monte Carlo simulations across a range of skin tones revealed that these optimal combinations vary with melanin concentration. Specifically, in subjects with lighter skin tones optimal sensitivity is achieved using shorter wavelengths and higher spatial frequencies, while for darker skin tones longer wavelengths and lower spatial frequencies are preferred. This approach simplifies clinical tracking of subsurface microstructural changes by eliminating the need for complex inverse problem solving, enabling rapid data acquisition and minimal processing
