[Six cases of secondary keratoconus with Fleischer's ring pattern corneal epithelial iron ring]

We observed 6 cases of secondary keratoconus with Fleischer's ring pattern corneal epithelial iron ring. These 6 cases were 2 males and 4 females. The causes of secondary keratoconus were 2 cases of trachoma, 2 cases of trauma, 1 case of keratitis, and 1 case of unknown origin. All showed thinning of the cornea and Fleischer's ring pattern corneal epithelial iron ring. After penetrating keratoplasty of 1 case, the button of the recipient showed the deposition of hemosiderin in the corneal epithelium stained blue by Prussian blue. At the same time we confirmed the existence of iron in the corneal epithelium by the X-ray ultimate analysis. Fleischer's ring is considered to be characteristic of keratoconus, but we have found that Fleischer's ring is also seen in secondary keratoconus in which the cornea becomes thinner secondarily for some reason.