Fig. 4

Demonstration of imaging across a variety of subjects with normal skin. Images of skin from sun-exposed, dorsal forearm in female participants with FST 2 or 3 of different ages: (a) age 24, (b) age 51, and (c) age 81. White triangles point to examples of green autofluorescence within the dermis. FOV setting; standard. Scale bar, 100 µm. SAAID values of dorsal forearm and ventral forearm dermis for (d, e) FST 1 and 2 (age < 30, n = 3; age > 49, n = 8).; (f, g) FST 3 (age < 30, n = 3; age > 49, n = 11); and (h, i) FST 4 and 5 (age < 30, n = 4; age > 49, n = 3). **, p < 0.01, effect size (ES) > 1.3; NS, not significant, p ≥ 0.05. (e, g, i) Linear trends of SAAID by age. Data points are skin regions of individual participants; ventral forearm by open circles with solid trendlines (R²: 0.77 [FST 1–2], 0.57 [FST 3], < 0.001 [FST 4–5]) and dorsal forearm by solid triangles with dotted trendlines (R²: 0.53 [FST 1–2], 0.47 [FST 3], 0.04 [FST 4–5]).