title: Very Low Prevalence of Keratoconus in a Large Series of Vernal Keratoconjunctivitis Patients.
abstract: OBJECTIVE
  To evaluate the prevalence of keratoconus (KC) and other corneal abnormalities by means of videokeratography and tomography in a large series of patients affected by vernal keratoconjunctivitis (VKC).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Setting: Single-center children's hospital.
  
  
  METHODS
  A total of 651 consecutive patients with VKC and a control group of 500 were prospectively recruited between May 1, 2012 and September 30, 2013, with a minimum follow-up of 12 months.
  
  
  METHODS
  All patients were evaluated by means of a Scheimpflug camera combined with a Placido corneal topographer. Keratoconus, suspected keratoconus, or its absence were determined in each patient. The corneal symmetry index of front (SIf) and back curvature (SIb), shape indices, and thicknesses were compared between the 2 groups.
  
  
  METHODS
  Prevalence of keratoconus and corneal indices modifications.
  
  
  RESULTS
  Five out of 651 patients (0.77%) demonstrated topographic signs of KC. Two of them were bilateral. All patients were older than 7 years of age, and the mean age was 11.54 years. Four other patients (0.61%) were classified as KC suspects by the screening program. Of 304 patients older than 11 years (mean age 14.4 years), 4 (1.32%) were found to have KCN, and 4 (1.32%) were KC suspects. The corneal indices of patients in the VKC group were extremely similar to those in the control group. (P > .05).
  
  
  CONCLUSIONS
  The prevalence of KC in our patient population, compared with previous reports in the literature, is much lower. The similar corneal indices in both groups suggest the absence of permanent corneal deformation due to VKC.
authors.affiliation: Pediatric Ophthalmology Unit, A. Meyer Children's Hospital, Florence, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Caputo
authors.affiliation: CSO srl, Florence, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Versaci
authors.affiliation: Pediatric Allergology Unit, A. Meyer Children's Hospital, Florence, Italy.
authors.forename: Neri
authors.initials: N
authors.lastname: Pucci
authors.affiliation: Pediatric Ophthalmology Unit, A. Meyer Children's Hospital, Florence, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: de Libero
authors.affiliation: Pediatric Ophthalmology Unit, A. Meyer Children's Hospital, Florence, Italy.
authors.forename: Gioia
authors.initials: G
authors.lastname: Danti
authors.affiliation: Statistics and Epidemiology Unit, A. Meyer Children's Hospital, Florence, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: De Masi
authors.affiliation: Ophthalmology Unit, Careggi Hospital, Florence, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Mencucci
authors.affiliation: Pediatric Allergology Unit, A. Meyer Children's Hospital, Florence, Italy.
authors.forename: Elio
authors.initials: E
authors.lastname: Novembre
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland. Electronic address: bjeng@som.umaryland.edu.
authors.forename: Bennie H
authors.initials: BH
authors.lastname: Jeng
mesh_terms: D000293:Adolescent; D002648:Child; D003233:Conjunctivitis, Allergic / Q000150:complications* / Q000175:diagnosis; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods*; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007558:Italy / Q000453:epidemiology; D007640:Keratoconus / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D015995:Prevalence; D012189:Retrospective Studies; D055815:Young Adult