title: Presence of Fleischer ring and prominent corneal nerves in keratoconus relatives and normal controls.
abstract: OBJECTIVE
  To examine the occurrence of commonly known clinical signs of keratoconus (KC), i.e. Fleischer ring, prominent corneal nerves and thinning, among unaffected family members of KC patients and healthy control individuals.
  
  
  METHODS
  Data of both eyes of 117 relatives of KC patients having no manifest disease based on videokeratography indices (KC relatives), and 142 controls were used for Pearson correlation and t-test statistics. Correlation of Fleischer ring, prominent corneal nerves and central pachymetry data were tested with each other and with videokeratography indices (KSI, KISA, 3 and 6 mm Fourier asymmetry, and I-S).
  
  
  RESULTS
  A moderate correlation was found between Fleischer ring and all examined topographical indices. Most important correlation was present with 6 mm Fourier asymmetry, and corneal pachymetry (r=0.272, P<0.001; r=-0.234, P=0.027, respectively). Similar correlations were found with prominent corneal nerves (r=0.234, P<0.001 for 6 mm Fourier asymmetry and r=-0.235, P=0.0265 for pachymetry). KC family members who exhibited Fleischer ring or prominent nerves had thinner and more asymmetric corneas than those without Fleischer ring or prominent corneal nerves (P<0.05 for pachymetry and topographic indices with t-test and Mann-Whitney rank sum test). Though rarely, Fleischer ring and prominent corneal nerves occurred among normal controls, indicating the existence of forme fruste cases in the normal population. Control subjects, who had corneal Fleischer ring or prominent nerves had corneas more similar to KC than other controls (t-test: increased KSI and KISA, P=0.048 and 0.012, respectively).
  
  
  CONCLUSIONS
  In KC family members and healthy individuals, Fleischer ring and prominent corneal nerves are associated with features of KC and may suggest a possibility of forme fruste KC. Searching for the possible presence of Fleischer ring or prominent nerves on the cornea may help in the decision whether or not to diagnose subclinical KC in a borderline case.
authors.affiliation: Department of Ophthalmology, University of Debrecen Clinical Center, Debrecen 4032, Hungary.
authors.forename: Ágnes
authors.initials: Á
authors.lastname: Kriszt
authors.affiliation: Department of Ophthalmology, University of Debrecen Clinical Center, Debrecen 4032, Hungary.
authors.forename: Gergely
authors.initials: G
authors.lastname: Losonczy
authors.affiliation: Department of Ophthalmology, University of Debrecen Clinical Center, Debrecen 4032, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Berta
authors.affiliation: Department of Ophthalmology, University of Debrecen Clinical Center, Debrecen 4032, Hungary.
authors.forename: Lili
authors.initials: L
authors.lastname: Takács
keywords: Fleischer ring; corneal nerves; corneal thinning; forme fruste/subclinical keratoconus; iatrogenic keratectasia; videokeratographic indices