ToF-SIMS and AFM Characterization of Brown Cosmetic Contact Lenses: From Structural Analysis to the Identification of Pigments
Table 2
Atomic force microscopic evaluation for root mean square roughness (Rrms) and average roughness (Ra) of the brown cosmetic contact lens at each area.
Samples
Position
Rrms (nm) (mean ± SD)
valuea for Rrms
Ra (nm) (mean ± SD)
valuea for Ra
CCL-A
(1) Central clear zone
3.57 ± 1.15
Clear: front
2.72 ± 0.82
Clear: front
0.0015
0.0014
(2) Front surface
26.19 ± 4.97
Front: back
21.03 ± 3.90
Front: back
0.0017
0.0014
(3) Back surface
3.75 ± 1.42
Back: clear
2.67 ± 1.02
Back: clear
0.8702
0.9564
CCL-B
(1) Central clear zone
7.40 ± 0.22
Clear: front
5.40 ± 0.41
Clear: front
0.0002
0.0002
(2) Front surface
49.98 ± 5.64
Front: back
39.35 ± 4.52
Front: back
0.0004
0.0003
(3) Back surface
9.86 ± 2.66
Back: clear
7.05 ± 1.45
Back: clear
0.1860
0.1308
CCL-C
(1) Central clear zone
5.12 ± 0.42
Clear: front
3.72 ± 0.54
Clear: front
0.0001
0.0001
(2) Front surface
43.17 ± 4.64
Front: back
33.44 ± 3.31
Front: back
0.0002
0.0001
(3) Back surface
8.34 ± 0.23
Back: clear
6.46 ± 0.19
Back: clear
0.0003
0.0012
Rrms: root mean square roughness; Ra: average roughness; SD: standard deviation. aComparison of lens surface roughness between different sides using the unpaired t-test. At the colored parts, all lenses with the surface pigment had significant difference of roughness between the front and back surfaces ( indicates statistical significance).