Figure 4 Proliferation assay: bevacizumab (0.5 mg/ml) significantly inhibits choroidal endothelial cell proliferation. Large cell‐free areas (CFAs) indicate strong antiproliferative effects. The CFA in the vascular endothelial growth factor (VEGF)‐enriched (50 ng/ml) control is only 0.18 mm² (p<0.05 compared with the control); addition of bevacizumab results in a CFA of 0.46 mm². This CFA is significantly larger compared with the control or with the VEGF‐stimulated sample (p<0.05). Deep freezing of bevacizumab leads to a moderate, but not significant, loss of antiproliferative activity (CFA  =  0.41 mm², p = 0.34). Compared with the VEGF‐enriched sample, there is a significant reduction of endothelial cell proliferation with frozen and thawed bevacizumab (p<0.05). SDs are shown.