title: Quantitative analysis of iris parameters in keratoconus patients using optical coherence tomography.
abstract: OBJECTIVE
  To investigate the relationship between quantitative iris parameters and the presence of keratoconus.
  
  
  METHODS
  Cross-sectional observational study that included 15 affected eyes of 15 patients with keratoconus and 26 eyes of 26 normal age- and sex-matched controls. Iris parameters (area, thickness, and pupil diameter) of affected and unaffected eyes were measured under standardized light and dark conditions using anterior segment optical coherence tomography (AS-OCT). To identify optimal iris thickness cutoff points to maximize the sensitivity and specificity when discriminating keratoconus eyes from normal eyes, the analysis included the use of receiver operating characteristic (ROC) curves.
  
  
  RESULTS
  Iris thickness and area were lower in keratoconus eyes than in normal eyes. The mean thickness at the pupillary margin under both light and dark conditions was found to be the best parameter for discriminating normal patients from keratoconus patients. Diagnostic performance was assessed by the area under the ROC curve (AROC), which had a value of 0.8256 with 80.0% sensitivity and 84.6% specificity, using a cutoff of 0.4125 mm. The sensitivity increased to 86.7% when a cutoff of 0.4700 mm was used.
  
  
  CONCLUSIONS
  In our sample, iris thickness was lower in keratoconus eyes than in normal eyes. These results suggest that tomographic parameters may provide novel adjunct approaches for keratoconus screening.
authors.affiliation: Cornea and Anterior Segment Service, The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, US.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Bonfadini
authors.affiliation: Dana Center for Preventive Ophthalmology, The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, US.
authors.forename: Karun
authors.initials: K
authors.lastname: Arora
authors.affiliation: Cornea and Anterior Segment Service, The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, US.
authors.forename: Lucas M
authors.initials: LM
authors.lastname: Vianna
authors.affiliation: Department of Ophthalmology and Visual Sciences, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, BR.
authors.forename: Mauro
authors.initials: M
authors.lastname: Campos
authors.affiliation: Dana Center for Preventive Ophthalmology, The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, US.
authors.forename: David
authors.initials: D
authors.lastname: Friedman
authors.affiliation: Dana Center for Preventive Ophthalmology, The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, US.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Muñoz
authors.affiliation: Cornea and Anterior Segment Service, The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, US.
authors.forename: Albert S
authors.initials: AS
authors.lastname: Jun
mesh_terms: D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000473:pathology; D003624:Darkness; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007498:Iris / Q000473:pathology* / Q000503:physiopathology; D007640:Keratoconus / Q000473:pathology* / Q000503:physiopathology; D008030:Lightning; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D041623:Tomography, Optical Coherence; D014792:Visual Acuity; D055815:Young Adult