title: Histopathologic findings of perforated corneas due to ferric ion infiltration.
abstract: OBJECTIVE
  To report the histopathologic findings of 3 corneal buttons incised from 2 patients during penetrating keratoplasty (PKP) because of corneal perforation due to corneal siderosis.
  
  
  METHODS
  Three eyes of 2 patients had accidental trauma to the corneas caused by iron fragments; the injuries were initially treated conservatively with antibiotics and therapeutic soft contact lenses. However, the corneal stroma melted and perforated, necessitating corneal transplantation. The corneal buttons removed during PKP were examined histopathologically, and the findings were compared with the slit-lamp biomicroscopic and anterior segment optical coherence tomographic (AS-OCT) findings.
  
  
  RESULTS
  Slit-lamp examinations showed that the corneal epithelium was hyperplasic around the area of perforation in 2 eyes 1 month after the injury. Wide areas of the stroma had melted, and the corneas were perforated. The corneal epithelium was atrophic in the perforated corneas 4 months after injury. Histopathologically, the corneal stroma and Descemet's membrane were stained by Prussian blue, suggesting that the ferric ions had penetrated deeper than expected by the slit-lamp examinations. The areas of Prussian blue staining corresponded well with the areas altered in the AS-OCT images.
  
  
  CONCLUSIONS
  Ferric ions penetrate much deeper into the cornea than estimated by slit-lamp biomicroscopy. The ferric ions can induce stromal melting that can lead to corneal perforation. We conclude that (i) the ferric ion-infiltrated areas can be estimated in the AS-OCT images and (ii) extensive corneal abrasion should be performed to prevent corneal melting and perforation.
authors.affiliation: Department of Ophthalmology, Mie University School of Medicine, Tsu City, Japan. Electronic address: k-kato@clin.medic.mie-u.ac.jp.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Kato
authors.affiliation: Department of Ophthalmology, Ban Buntane Houtokukai Hospital, School of Medicine, Fujita Health University, Nagoya, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Hirano
authors.affiliation: Department of Ophthalmology, Mie University School of Medicine, Tsu City, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Takashima
authors.affiliation: Department of Ophthalmology, Mie University School of Medicine, Tsu City, Japan.
authors.forename: Satoe
authors.initials: S
authors.lastname: Sakamoto
authors.affiliation: Department of Ophthalmology, Mie University School of Medicine, Tsu City, Japan.
authors.forename: Mineo
authors.initials: M
authors.lastname: Kondo
mesh_terms: D000368:Aged; D057112:Corneal Perforation / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D005129:Eye Foreign Bodies / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D015807:Eye Injuries, Penetrating / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D005290:Ferric Compounds / Q000378:metabolism; D006801:Humans; D007501:Iron; D015948:Keratoplasty, Penetrating; D008297:Male; D008669:Metallurgy; D008875:Middle Aged; D060051:Occupational Injuries / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D041623:Tomography, Optical Coherence
chemical_list: D005290:Ferric Compounds; D007501:Iron