Optic nerve axon size. The median axon diameter of uninjected eyes (A) was larger in nerves from Fbn1Tsk/+ mice (red bar) as compared with wt (blue bar). Histograms of pooled axon diameters of uninjected eyes (B) show a shift toward larger axons in Fbn1Tsk/+ mice (red bars) compared with wt (blue bars). Paired analysis (C) comparing nerves from uninjected (left symbols) with those from bead-injected eyes (right symbols) showed no change in median axon diameter for wt (blue symbols) and Fbn1Tsk/+ mice (red symbols). Histograms of pooled axon diameters were very similar for uninjected (dark bars) and microbead-injected (light bars) for wt (D) and Fbn1Tsk/+ mice (E). Numbers of animals: 32 wt and 18 Fbn1Tsk/+ (A and C). Numbers of axons included for each histogram: 1,105,075 for wt un-injected, 1,014,017 for wt injected, 684,888 for Fbn1Tsk/+ un-injected and 616,953 for Fbn1Tsk/+ injected (B, D, and E). Dashed lines connect paired eyes (C).