Skin damage from laser radiation is not as great a concern as eye damage; such skin injury can be treated similarly to treatment of a thermal burn or wound. Further, in power or energy densities high enough to cause skin damage, the laser beam is usually enclosed, or some form of physical protection is provided for personnel. If this is not done, laser operators must wear protective clothing. Knowledge of skin damage thresholds also helps to evaluate optical densities of eyewear; if the need for high optical densities (above 5 or 6 in most cases) is specified, simple calculations will show that the power or energy density anticipated for the laser beam will be above the skin damage threshold as explained in specific cases in Chapter 8.