**Figure 4.** **Lens stiffness and resilience for mouse lenses between 2–30 months of age.** Plots reflect mean ± SD of n = at least 8 lenses per age. The graph next to the data plots shows the 95% confidence interval. Any comparisons not crossing the dotted line are statistically significant (p < 0.05). (**A**, **B**) Compression testing using sequential application of coverslips showed a steady decrease in axial and equatorial strain with age, indicating that lenses from older mice are stiffer. (**C**) Very old lenses from 30-month-old mice had increased resilience, calculated as the ratio of the pre-compression over post-compression axial diameter. Resilience for 30-month-old lenses was 98.8% ± 1.2% while resilience for younger lenses was ~94-96%.