title: Characteristics and associations of keratoconus patients.
abstract: OBJECTIVE
  To determine the characteristics and risk factors of keratoconus (KC) patients and the possible associations between these characteristics and the severity of KC.
  
  
  METHODS
  A prospective case-control study was performed in a referral eye hospital, recruiting KC patients and comparing their demographic and clinical characteristics with age and sex-matched control subjects to determine factors associated with KC. Mean keratometry (mean K) and central corneal thickness (CCT) of KC patients were recorded and compared. The severity of KC was further compared with the characteristics of KC patients.
  
  
  RESULTS
  A total of 922 KC patients and controls were enrolled in the study. The mean age at the first presentation of KC patients was 21.03±6.17 years. The most frequent presenting symptom was blurred vision. The multivariate analysis revealed that KC in relatives, eye rubbing, itchy eyes, and low educational level are independent predictors of KC. Severity of KC was moderate in 43.8% and severe in 41% of the patients. None of the proposed characteristics were significantly associated with mean K and CCT. KC patients with a higher frequency of eye rubbing, family history of KC and more KC members in their family had a more severe KC, while diabetic patients had a less severe KC.
  
  
  CONCLUSIONS
  This study presented an overview of a large population of KC patients in Iran, emphasizing the associated risk factors for this condition. Our findings add weights to the evidences that eye rubbing and positive family history of KC are independent risk factors for developing KC.
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: Moh@Naderan.com.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Naderan
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Shoar
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Rezagholizadeh
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Masoome
authors.initials: M
authors.lastname: Zolfaghari
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Morteza
authors.initials: M
authors.lastname: Naderan
mesh_terms: D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D007492:Iran / Q000453:epidemiology; D007640:Keratoconus / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014792:Visual Acuity; D055815:Young Adult
keywords: Clinical presentations; Eye rubbing; Family history; Keratoconus; Risk factors; Severity