title: Bilateral circumscribed posterior keratoconus.
abstract: BACKGROUND
  Posterior keratoconus is a rare corneal disorder characterized by a diffuse or localized protrusion of the posterior corneal surface into a thinning stroma. It is believed to be a congenital, nonprogressive condition.
  
  
  METHODS
  A case of bilateral circumscribed posterior keratoconus is presented. Diagnostic ocular signs include localized protrusion of the posterior corneal surface, normal anterior corneal surface, stromal thinning, and endothelial changes. However, anterior corneal contour reveals progressive steepening in this case.
  
  
  CONCLUSIONS
  Posterior keratoconus is an unusual corneal anomaly with subtle clinical features. Recognition of these signs is essential in the diagnostic and management processes.
authors.affiliation: Illinois College of Optometry, Illinois Eye Institute, Chicago, USA.
authors.forename: D Q
authors.initials: DQ
authors.lastname: Chan
mesh_terms: D003261:Contact Lenses; D003319:Corneal Stroma / Q000473:pathology*; D019781:Corneal Topography; D003937:Diagnosis, Differential; D004728:Endothelium, Corneal / Q000473:pathology*; D005139:Eyeglasses; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000151:congenital / Q000175:diagnosis* / Q000628:therapy; D008875:Middle Aged; D055656:Prescriptions; D014792:Visual Acuity