title: Prevalence of sleep apnea in patients with keratoconus.
abstract: OBJECTIVE
  To determine the prevalence of obstructive sleep apnea (OSA) in patients with keratoconus and evaluate the risk of developing OSA in this patient population.
  
  
  METHODS
  Three hundred sixty-two patients diagnosed with keratoconus by a single physician at the Duke Eye Center over a 14-year period were identified. A power calculation was done a priori, and based on this, the first 101 patients were enrolled. All patients were administered a standardized questionnaire regarding medical and ocular health. Those without the history of OSA were administered the Berlin questionnaire to determine their risk for developing OSA. Statistical analysis was performed to determine the prevalence of OSA and to compare it with previously reported prevalence data in the general population.
  
  
  RESULTS
  The prevalence of previously diagnosed OSA was 18% (18 of 101); all reported having a formal sleep study in the past. Of the remaining patients (n = 83), 47% (39 of 83) were determined to be at high risk for the development of OSA determined by the Berlin questionnaire score. Comorbid health conditions included hypertension (37%), acid reflux (30%), diabetes mellitus (20%), and seasonal allergies (66%). A history of penetrating keratoplasty was found in 48%. The average body mass index of the study population was 31.2 (median, 28.4).
  
  
  CONCLUSIONS
  Keratoconus patients have a higher prevalence of OSA compared with that accepted for the general population. A striking number of our patients without previous diagnosis of OSA seem to be at high risk for developing OSA, supporting our recommendation for a greater awareness among clinicians who might otherwise overlook this systemic condition and its consequences.
authors.affiliation: Department of Ophthalmology, Duke Eye Center, Durham, NC 27710, USA.
authors.forename: Preeya K
authors.initials: PK
authors.lastname: Gupta
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Stinnett
authors.forename: Alan N
authors.initials: AN
authors.lastname: Carlson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015897:Comorbidity; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000453:epidemiology*; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D009657:North Carolina / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D055815:Young Adult