A typical white ring of the cornea, as originally described by Coats, was excised from an eye which was normal except for the presence of asteroid hyalosis. The composition of the lesion was studied. It was found to contain iron and to be negative for lipid and calcium. The presence of iron was substantiated by electron probe x-ray microanalysis. Iron has not been previously reported in this lesion.
Nevins RC, Elliott JH. White Ring of the Cornea. Arch Ophthalmol. 1969;82(4):457-460. doi:10.1001/archopht.1969.00990020459006