Figure 1. Halofuginone is nontoxic at low concentrations. The viability of human corneal fibroblasts treated with halofuginone is similar to control for concentrations of 10 ng/ml or less. The viability of cells treated with 50 ng/ml or 100 ng/ml halofuginone is significantly decreased compared to control (* p<0.005). Viability is expressed as fluorescence intensity of metabolized resazurin relative to control (n=5, bar=S.E.M.).