• In two cases scheduled for corneal transplantation, edges of donor corneal buttons were discolored by a black contaminant transferred from the disposable trephines. Trephines from two different manufacturers produced this same problem. Scanning electron microscopy and energy-dispersive x-ray analysis indicated that the contaminant was a mixture of stainless steel particles from the trephine and silicon carbide abrasive used in sharpening.
Pardos GJ, Meltzer DW. Particulate Contamination in Disposable Corneal Trephines. Arch Ophthalmol. 1983;101(4):562-563. doi:10.1001/archopht.1983.01040010562005