Methods for ascertaining, and responding to, a tissue characteristic of a surface region of patient tissue are disclosed. A scanned beam device is used to transmit a beam of sensing radiation to impinge on the surface region and to measure the reflectance of the surface region from the collected radiation returned from the surface region. The tissue characteristic of the surface region is determined from the measured reflectance, wherein the tissue characteristic is different from but related to the measured reflectance. In a first method, an indication of the determined tissue characteristic is provided, wherein the indication is other than a displayed image of the surface region. In a second method, wherein the patient tissue is undergoing medical treatment, the medical treatment is automatically modified as a function of the determined tissue characteristic. A scanned beam device having a scanning beam unit, a collector, and a controller is also disclosed.
