title: Association between Family History and Keratoconus Severity.
abstract: The high prevalence of positive family history of keratoconus (KC) in KC patients is well-known. However, the results regarding the association between family history of KC and disease severity are controversial. The aim of this study was to evaluate the possible association between family history and severity of KC.
  
  
  
  Clinical data of 1496 KC patients were evaluated. All participants were asked if they had had a family member with KC. Topographic and keratometric measurements of KC patients, including central corneal thickness (CCT), thinnest corneal thickness (TCT), mean, flat, and steep keratometry values (K) by the use of Pentacam, best-spectacle corrected visual acuity (BCVA), spherical equivalent (SE), and astigmatism were recorded and compared according to patients with and without a family history of KC, first- or second-degree family members, and the number of family members with KC. Severity of KC was classified according to the Amsler-Krumeich classification.
  
  
  
  Family history of KC was present in 292 (19.5%) patients. Of those 292 patients who had a family history of KC, 159 (54.5%) had one family member with KC and 133 (45.5%) had two or more family members with KC. There was not a significant difference between corneal pachymetry and K values of the patients with and without a family history of KC (p > 0.05). However, those with a positive family history of KC had more severe disease, according to the Amsler-Krumeich classification (p < 0.05). KC patients who had more family members with KC had significantly lower TCT and significantly higher steep K and astigmatism (p < 0.05), and had more severe disease, according to the Amsler-Krumeich classification (p < 0.05).
  
  
  
  We suggest that patients with more family members with KC should be subject to screening to identify early disease.
authors.affiliation: a Eye Research Center, Farabi Eye Hospital , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Naderan
authors.affiliation: a Eye Research Center, Farabi Eye Hospital , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Mohammad Taher
authors.initials: MT
authors.lastname: Rajabi
authors.affiliation: b Zarrinbakhsh Eye Clinic , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Parviz
authors.initials: P
authors.lastname: Zarrinbakhsh
authors.affiliation: a Eye Research Center, Farabi Eye Hospital , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Morteza
authors.initials: M
authors.lastname: Naderan
authors.affiliation: a Eye Research Center, Farabi Eye Hospital , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Anahita
authors.initials: A
authors.lastname: Bakhshi
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology*; D063171:Corneal Pachymetry; D019781:Corneal Topography / Q000379:methods*; D003430:Cross-Sectional Studies; D005190:Family; D005260:Female; D006801:Humans; D015994:Incidence; D007492:Iran / Q000453:epidemiology; D007640:Keratoconus / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D012720:Severity of Illness Index; D014792:Visual Acuity; D055815:Young Adult
keywords: Corneal topography; family history; keratoconus; risk factor; severity