ABSTRACT
Dermoscopy permits visualization of structures, patterns, and colors in skin lesions that are not evident to the naked eye. Nonpolarized dermoscopy (NPD) and polarized dermoscopy (PD) are distinct imaging modalities that provide complementary information. Dermoscopy works threw, modifying the cutaneous air–tissue optical interface. When incident visible light reaches the skin surface, approximately 4%–7% will be normally reflected back due to the change in refractive index between air and stratum corneum. NPD changes the air–tissue optical interface through the use of a contact glass plate and liquid interface that together approximate the refractive index of the stratum corneum. PD uses two polarizers with orthogonal axes to emit cross-polarized light. Skin surface or superficial epidermal details, including milia-like cysts, comedo-like openings, and blue–white veil, may be poorly visualized or completely absent with PD and are best identified using NPD. In contrast, white shiny structures are only seen with PD.
