Figure 5.

Average first principal strains for control (horizontal axis) and stiffened (vertical axis) regions of eyes treated with (a) genipin, (b) glyceraldehyde or (c) methylglyoxal. Each dot represents the mean steady-state strain for one eye, and the surrounding oval represents the 95% CI of that point from linear fitting. Points falling below the unity line (black line) indicate that the treated eye has been stiffened relative to the control, and vice versa. The dotted line represents 100% stiffening. Eyes in red lie very close to the unity line, suggesting that this low dose has a minimal stiffening effect. Higher concentrations lie further from the unity line until reaching a maximum effective dose around 7 mM for genipin, 62.5 mM for glyceraldehyde and 14 mM for methylglyoxal. Higher concentrations do not further stiffen the experimental half of the eye but do reduce strain in the control portion of the eye, possibly as a result of diffusion into the internal tissues of the eye and cross-linking them.