Table 2. Reported sensations and signs of skin damage on each NIR laser dose.

	Subjects					Number of sensations			Total events
Laser irradiances (W/cm2)	1	2	3	4	5	Mild	Moderate	Severe
0.5						0	0	0	0
0.7						0	0	0	0
0.8						0	0	0	0
1.1						0	0	0	0
1.4					1	1	0	0	1
1.5					1,2	1	1	0	2
1.7						0	0	0	0
2.2			4			1	0	0	1
2.5	4		4			2	0	0	2
2.7			4	4	1	3	0	0	3
2.9	1,2		1,2	4	1,2	4	3	0	7
3.1	1,2		1	4		3	1	0	4
3.3	1			4	1,2	3	1	0	4
3.4	1,9	4,9	1			3	0	0	5
3.5	9	4,9	1	1	1,2	4	1	0	7
3.7	2,9	9	1,2	1	1,2,9	3	3	0	9

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