Patent ID: 8620411

Claim:
A method of assessing skin health, effects of aging, photoaging, or diabetic condition of a subject in question, said method comprising: a. creating a control ratio by (I) exposing a first area of skin not readily exposed to UV radiation of the subject in question to a first exposure radiation to induce said first area of skin to emit a first fluorescent emission, wherein said first exposure radiation comprises primarily of wavelengths of from about 290 nm to about 300 nm; (II) measuring the intensity of said first fluorescent emission having a wavelength of from about 320 nm to about 350 nm to determine the amount of tryptophan in the skin; (III) exposing said first area of skin to a second exposure radiation to induce said first area of skin to emit a second fluorescent emission, wherein said second exposure radiation comprises primarily of wavelengths of from about 330 nm to about 420 nm; (IV) measuring the intensity of said second fluorescent emission having a wavelength of from about 380 nm to about 470 nm to determine the amount of collagen cross-links in the skin; (V) calculating a ratio of said intensity measured in step (II) to said intensity measured in step (IV) to form a control ratio that cancels the effect of pigmentation to get a first tryptophan fluorescence parameter related to health and independent of pigmentation; b. performing the measurements of steps (I), (II), (III) and (IV) for the subject in question on a second area of skin readily exposed to UV radiation; c. calculating a ratio of the intensity measurements of step (II) of step b to the intensity measurement of step (IV) of step b for the subject in question to form a test ratio that cancels the effect of pigmentation to get a second tryptophan fluorescence parameter related to health and independent of pigmentation; and d. comparing said test ratio to said control ratio to determine the skin health, effects of aging, photoaging, or diabetic condition of the subject in question.