Visible and infrared high-power lasers can cause permanent skin and organ damage if used inappropriately.
Patient protection measures, government and institutional guidelines, and familiarity with the physics behind laser technology are means by which dermatologists can optimize safety, Dr. E. Victor Ross said at a cosmetic dermatology seminar sponsored by Skin Disease Education Foundation in Santa Monica, Calif.
Dr. E. Victor Ross
Mild to severe reddening, blisters, charring, depigmentation, ulceration, and scarring are among possible adverse effects when these devices are not employed safely, he said.
Even when just the skin is being treated, protective measures are warranted for the eyes, said Dr. Ross, director of the Scripps Clinic Laser and Cosmetic Dermatology Center in Carmel Valley, Calif.
Visible light and some infrared-wavelength light is focused as it enters the eye, making the eyes even more susceptible to laser damage. There have been reports of severe and sometimes permanent eye injuries with lasers. One patient, for example, reported seeing a white flash and hearing a click during treatment with an Nd:YAG 1064-nm laser. The result was a dark spot in the patient's visual field resulted, he said.
Protective eyewear is of paramount importance, Dr. Ross said. Select eyewear based on the laser and the anatomic region being treated. Look for eyewear marked with the wavelengths it protects against and the degree of light energy attenuation. Caution is advised when using goggles on pediatric patients because the fit may not be ideal.
In a very practical sense, Dr. Ross also advised that staff keep cups of water or coffee off the lasers. A spill or leak can get into the device power supply and cause an "explosion." In addition, never open the part of the laser where the high voltage energy is located, said Dr. Ross.
He recommended following the American National Standards Institute's (ANSI) series of laser safety standards. The recommendations are recognized by many hospitals as the standard for guiding a laser safety program, he said.
Examples of ANSI standards include physicians acting as the safety officer, routine laser maintenance, and having a set of standard operating procedures that is kept on file. Recommendations are not just for large practices, Dr. Ross said. "Even a small clinic should have a laser safety officer."
Government safety standards for laser use are available from the Occupational Safety and Health Administration and the Food and Drug Administration's Center for Devices and Radiological Health. Having a sign posted near each device warning of potential hazards specific to that class of laser is an example of a government safety standard, he said.
There are four general safety categories for lasers:
Class 1. Low-power device that is considered safe.
Class 2. The eye blink response generally provides enough eye protection during use.
Class 3. Direct exposure of the eye to these medium-power devices has potential to cause harm.
Class 4. These high-power devices require the most caution to avoid eye and skin hazards through direct and reflected exposure. These lasers also can pose a fire hazard if nearby materials are accidentally ignited from direct or scattered beams.
Credentialing is another safety measure. All clinicians operating a laser at the Scripps Clinic, for example, must be credentialed for that specific device and wavelength. Requirements include some didactic training, supervision during three or more laser treatments, and hands-on instruction by the device manufacturer, Dr. Ross said.
As with most government standards, there is official terminology regarding laser safety. Maximal permissible exposure (MPE) is an official term, describing the amount of irradiance to which a patient can be exposed without causing eye or skin damage. It is important to note that patient discomfort is possible within the MPE limitations. The MPE is calculated using wavelength and duration of laser exposure.
Dermatologists can optimize safety with knowledge of the basic physics behind the energy delivered in laser light and how it provides benefits to the skin when delivered properly, he suggested.
Power delivered per unit area is called the irradiance. This is typically expressed as the power in watts per square centimeter. Many dermatologists and device manufacturers compare lasers and outcomes in terms of joules, which is the energy delivered per square centimeter.
On the patient end, science determines the depth to which laser light penetrates and is absorbed. This absorption coefficient varies among hemoglobin, melanin, and water, for example. Each component interacts to a different extent with laser energy, and dermatologists utilize this selective photothermolysis to optimize patient outcomes from laser treatments, he said.
Dr. Ross disclosed that he is a researcher for and receives funding from multiple laser companies, including Candela, Cutera, Lumenis, Sciton, and Syneron.