title: Differences in corneal anatomy in a pair of monozygotic twins due to continuous contact lens wear.
abstract: OBJECTIVE
  To study the differences in the corneal anatomy in a pair of 31-year-old monozygotic female twins, one of whom has been a contact lens wearer for the past 15 years and the other is a nonwearer.
  
  
  METHODS
  We analyzed the corneal thickness and the corneal endothelial cell density of the monozygotic twins and of two age-matched control groups, one made up of non-contact lens wearers (35 eyes of 35 patients; mean age, 29.32 +/- 2.83 years) and the other made up of soft contact lens wearers (30 eyes of 30 patients; mean age, 33.08 +/- 3.72 years; mean duration of contact lens use, 10.62 +/- 4.32 years). Five corneal thickness measurements were carried out with the Orbscan Topography System II. Three consecutive measurements of the corneal endothelial cell density were carried out with the Topcon SP-2000P noncontact specular microscope.
  
  
  RESULTS
  Lower central corneal endothelial cell densities were found in both eyes of the monozygotic contact lens-wearing twin. The greater corneal thickness was shown at superonasal cornea except in the right cornea of the monozygotic contact lens twin. Moreover, significant differences in corneal thickness values were found between the monozygotic twins.
  
  
  CONCLUSIONS
  The differences between the monozygotic twins seem to confirm that daily use of soft contact lenses can modify normal corneal anatomy.
authors.affiliation: Department of Anatomy and Human Embryology, University of Valencia, Faculty of Medicine, Spain. juan.sanchis@uv.es
authors.forename: Juan A
authors.initials: JA
authors.lastname: Sanchis-Gimeno
authors.forename: A
authors.initials: A
authors.lastname: Lleó
authors.forename: L
authors.initials: L
authors.lastname: Alonso
authors.forename: M S
authors.initials: MS
authors.lastname: Rahhal
authors.forename: F
authors.initials: F
authors.lastname: Martínez-Soriano
mesh_terms: D000328:Adult; D002452:Cell Count; D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects*; D003316:Corneal Diseases / Q000175:diagnosis / Q000209:etiology*; D019781:Corneal Topography; D004200:Diseases in Twins; D004728:Endothelium, Corneal / Q000473:pathology*; D005260:Female; D006801:Humans; D014430:Twins, Monozygotic