Topic Completed: 1 October 2013

Revised: 27 March 2019

Copyright: 2004-2019, PathologyOutlines.com, Inc.

PubMed Search: Keratoconus [title] pathology [title]

Nat Pernick, M.D.
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Cite this page: Pernick N. Cornea: keratoconus. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/eyecorneakeratoconus.html. Accessed August 25th, 2019.
Definition / general
  • Common, incidence of 1 per 2000
  • Congenital ectasia of central cornea, usually identified by age 9 years
  • Usually bilateral
  • Associated with Down syndrome, Marfan syndrome and atopic disorders
  • Progresses until fibrosis decreases vision
  • May have sudden rupture of Descemet membrane, allowing aqueous humor to enter corneal stroma, causing corneal hydrops and sudden worsening of vision
  • Causes scarring and astigmatism which cannot be corrected by glasses; may be corrected by rigid contact lenses
  • Corneal transplantation
Gross description
  • Wrinkled corneal button after transplantation
  • Cornea is cone shaped
  • Often has Fleischer ring (brown, stainable intraepithelial iron arc surrounds conical portion of cornea)
Microscopic (histologic) description
  • Thinning and fibrosis of cornea
  • Numerous breaks in Bowman layer
  • No inflammation or vascularization
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