title: Unilateral keratoconus: videokeratography and Orbscan study--optical correction.
abstract: OBJECTIVE
  To assess the frequency of unilateral keratoconus (KC) and vision correction with a contact lens (CL) in the KC eye.
  
  
  METHODS
  Transverse study in which we revised the clinical records of 385 KC patients. Of these, 35 (9%) showed clinical unilateral KC. Corneal topography was evaluated by a Placido disk and an elevation topographer. We also determined distance and near visual acuity before and after correction with spectacles or CL in KC eye.
  
  
  RESULTS
  Mean central corneal curvature (K) of the KC eyes was 51.45 +/- 6.65 D, versus 43.58 +/- 1.71 D for the fellow eye (P<0.001). Mean maximum curvature of the inferior cornea was 54.62 +/- 5.91 D in the KC eye and 44.66 +/- 2.38 in the fellow eye (P<0.001). Mean of the thinnest point pachymetry was 411 +/- 55 microm in the KC eye and 477 +/- 42 microm in the contralateral eye (P<0.0001). In most of the 29 patients in whom CLs were fitted, aspheric rigid gas-permeable CLs were used, corrected visual acuities were significantly better (P<0.0001) than without correction.
  
  
  CONCLUSIONS
  All unilateral KC patients showed higher corneal curvature in the affected eye. Corneal thickness was likewise clearly reduced in the KC eye, and reduced with respect to normal values in the contralateral eye. Aspheric rigid gas-permeable CL were the most effective for improving distance and near visual acuity in patients with adequate tolerance.
authors.affiliation: Instituto Galego de Oftalmoloxía, Escola Universitaria de Optica e Optometría, Universidad de Santiago de Compostela, Spain. mariaisabel.lema@usc.es
authors.forename: Isabel
authors.initials: I
authors.lastname: Lema
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Suárez
authors.forename: Elío
authors.initials: E
authors.lastname: Díez-Feijoo
mesh_terms: D000293:Adolescent; D000328:Adult; D003261:Contact Lenses; D019781:Corneal Topography / Q000379:methods*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005740:Gases; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis* / Q000503:physiopathology / Q000534:rehabilitation; D008297:Male; D008875:Middle Aged; D010539:Permeability; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D005740:Gases