Different patterns of iron deposition in the epithelium in 96 of 120 corneal buttons that had superficial irregularities of different causes, as examined after staining grossly with Prussian blue by Gomori's method were detected. These observations were confirmed by light microscopy in 86 cases. The deposition was either diffuse or it formed a linear pattern within the epithelium adjacent to elevated areas of corneal scarring. The authors believe that the tear film is the source of iron in these cases, and that relative pooling of tears on an irregular surface is the mechanism by which iron lines are formed.