Age-related discontinuous changes in the in vivo fluorescence of human facial skin

We measured the 325-nm laser-induced fluorescence of the skin of the face and ventral forearm in seventy Japanese female volunteers, and evaluated the effects of age and exposure to sunlight. The subjects were arbitrarily grouped into 10-year age-groups. In slightly exposed areas such as the ventral forearm, the average laser-induced intensity ratio at 390 nm to 430 nm showed no significant differences with the age group. In areas markedly exposed to sunlight such as the corners of the eyes and mouth, the average laser-induced intensity ratio showed a discontinuous decrease with age. These findings suggested that dermal fluorophore changes differ with the skin areas and are affected by sunlight exposure.