Certain dermoscopic structures are more conspicuous with nonpolarized dermoscopy (NPD), while others are more conspicuous with polarized dermoscopy (PD) .
The introduction of hybrid dermoscopes now allow the user to toggle between polarized and nonpolarized light. We found that structures that are more conspicuous with either NPD or PD appear to “blink” when the observer toggles between light modes.
In our experience, the presence of crystalline structures, which can easily be confirmed via the blink sign, can assist in detecting amelanotic and nodular melanoma, thereby increasing diagnostic sensitivity. The presence of multiple milia cysts, which can also easily be seen via the blink test, increases diagnostic specificity by helping to correctly identify seborrheic keratosis.