Sickle retinopathy in HbSC mice. Retinal vasculature was visualized after IV fluorescein isothiocyanate-dextran injections in 7-month-old AA, SC, and SS mice, and images were captured after dissection of the retina by a Nikon C2 confocal laser scanning microscope. Representative images of the retina in AA (A), SC (B), and SS (C) are shown. (D-F) Magnifications of the boxed areas from panel B (HbSC retina) show the neovascularization and abnormal blood vessel growth, “comma”-shaped vessels, and vascular leakage. (G) Percentage of mice with retinopathy (n = 6 in the SC and SS groups, n = 3 in the AA group of mice). No AA mice had retinopathy. Statistics were performed using ANOVA. ∗P < .05. Whole-blood viscosity in mice (H) and human samples (I) is shown at 5 different shear rates. Each line represents the mean + standard error of the mean of 3 to 6 mice or human blood samples per group. cP, centipoise.