Reported sensations and signs of skin damage on each NIR laser dose.

Consenting human subjects were exposed to a range of laser doses from 0.5 to 3.7 W/cm2 (16 doses) each up to 120 seconds. Sensations felt by subjects were classified as mild (warmth, tingling, itching, pinprick/needle sensations), moderate (hotness, dull pain), or severe (burning, sharp pain), and recorded. The operator also recorded any signs of skin damage. 1Warmth 2Hotness 3Burning 4Pinprick/needle sensations 5Dull pain 6Sharp pain 7Tingling 8Itching 9Skin appearance change; No changes in skin appearance or damage were noted on all exposures, except transient skin darkening (transient hyperpigmentation) occurred in some subjects, which was due to changes in capillary blood flow in the treated area. These changes were not observed during follow-up examination after 2 hours. 10Skin damage