• Linear iron deposits in the corneal epithelium are well-documented phenomena in a variety of circumstances, both normal and pathologic. A characteristic annular pigmented line, appearing clinically as an "iron" line, occurred in the donor epithelium of approximately 13% of corneal grafts with retained sutures. Eight cases of normally functioning grafts had iron lines located just central to the sutures. These lines appeared at various intervals postoperatively and did not correlate with age or race. They were frequently found in association with other surface-related epithelial and subepithelial phenomena and were believed to be related to peripheral corneal topography and the lid-cornea interface. Although they are clinically iron, their precise histochemistry, cause, source, and natural history are yet to be determined.
Mannis MJ. Iron Deposition in the Corneal GraftAnother Corneal Iron Line. Arch Ophthalmol. 1983;101(12):1858-1861. doi:10.1001/archopht.1983.01040020860003