NEWS, VIEWS, AND REVIEWS: A Tool for My Laser Practice I Simply Can’t Do Without: Shining a Light on My Favorite Light (Source)

Every laser practitioner has a tool they simply cannot do without. If it’s left at a satellite office or gets misplaced, then it’s going to be a stressful day. For me that device is the Syris Scientific v900L, formerly known by the much cooler name of the Seymour Light, because it truly allows physicians to SEE MORE than they could ever see with even the best external lighting. It all began with three of my favorite people, who also happen to be world-class photobiologists, back in the early 1990s. In July of 1991, R. Rox Anderson, MD, described the use of polarized light in dermatology in an article in Archives of Dermatology called “Polarized Light Examination and Photography of the Skin.” (Arch Dermatol 1991; 127:1000-1005). Then in 1997 Rox Anderson, Nik Kollias, and Bill Farinelli developed the first patented, polarized hands-free headset; known as the Seymour Light (Figure 1). This first commercial iteration of a head lamp that incorporated the very simple (once one has seen it or heard about it) concept of using 2 polarizers that can be oriented at different angles to one another, and are positioned between the observer and a light source, providing illumination and magnification with continuous options for polarization. One polarizer is directly in front of a bright halogen bulb, and this polarizer can be rotated 90 degrees by the user. The other polarizer is fixed and is in front of a plastic viewing-shield, which contains magnifiers of various selected strengths.One who wears polarized sun glasses has probably had the experience of looking at controls in a car that are covered by a plastic lens, or a computer screen with a plastic covering, and found that the screen goes from visible to poorly-visible, to opaque, when turning one’s head to change the orientation of the polarizing sun glasses. A polarizer only transmits light waves of a particular orientation, or polarization, to come through. This simple example illustrates that combining 2 polarizers of opposite orientations will eliminate all light coming from a particular source, and rotating one’s head to change the orientation of one’s sun glasses relative to a computer screen or automobile display will allow varying amounts of visibility depending upon the relative orientation of the 2 polarizers, from complete visibility when the orientation of the polarizers are parallel to one another (parallel-polarized), to no visibility when the polarizers are at right angles to one another (crosspolarized).This concept is exploited for photography, especially dermatologic photography, when trying to highlight various features of the skin. When photographing spider veins, pigmentation, tattoos or any cutaneous feature below the stratum corneum or very superficial epidermis, cross-polarized flash photography is used to expose an unseen world beneath the skin surface, eliminating surface shadows and reflections or glare. Typically, a polarizer is placed in front of the flash and another is placed at right angles to it in front of the lens (Figure 2). This is analogous to the cross-polarized position with the Syris light. When highlighting surface features one removes the polarizer for plain flash photography, or with the Syris light, turns the movable polarizer so that it is parallel to the fixed polarizer in front of the viewing window.