Figure 2.

Effects of compressive forces on indentation of the COC matrix: elastic versus plastic and viscous deformation. (A and B) Representative curves of force versus distance from contact point δ, measured on COCs expanded in vivo (A) and in vitro (B). The first and second approach curves obtained at a previously unperturbed position on the COC are shown for two selected approach speeds (1 μm/s and 20 μm/s, as indicated). (C and D) Slopes measured between δ = 25 and 30 μm in series of force versus distance curves acquired at fixed positions with varied approach speed, normalized by the slope at 20 μm/s. Data represent the mean ± standard deviation from measurements on three COCs each, expanded in vivo (C) and in vitro (D).