Differences between polarized and non-polarized dermoscopy

	Non-polarized dermoscopy (NPD)	Polarized dermoscopy (PD)
Technique	Requires direct contact between the scope and the skin. Requires a liquid interface.	Although PD can be used in either the contact or non-contact mode, and can be used with or without a liquid interface, using a liquid interface and direct contact provides superior image clarity.
Skin layers	Superficial layers are better visualized than deeper layers.	Deep layers of epidermis and papillary dermis (depth of polarized light ~60 to 100 micrometers) are better visualized than superficial layers.
Colors and structures	Blue white-veil due to orthokeratosis is more conspicuous.	Pink and red colors are more conspicuous.
	Milia-like cysts and comedo-like structures are easier to recognize under NPD.	Milia-like cysts and comedo-like structures are less conspicuous with PD.
	The steel-blue color seen in blue nevi appears more homogeneous under NPD.	The blue color in blue nevi will appear darker with differing hues.
	Regression areas (peppering, blue white areas and gray color) are more conspicuous with NPD. This difference is especially pronounced on thin skin such as facial or sun-damaged skin.	The white scar-like areas are more conspicuous under PD.
	The ability to visualize vascular structures is dependent upon the amount of pressure applied to the skin.	Vascular structures and collagen are more conspicuous.
		Shiny white structures, including white shiny streaks, also known as crystalline structures, are only seen under PD.

Data from:

Pan Y, Gareau DS, Scope A, et al. Polarized and nonpolarized dermoscopy: the explanation for the observed differences. Arch Dermatol 2008; 144:828.
Benvenuto-Andrade C, Dusza SW, Agero AL, et al. Differences between polarized light dermoscopy and immersion contact dermoscopy for the evaluation of skin lesions. Arch Dermatol 2007; 143:329.

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