title: Comparison of optical coherence tomography and ultrasound biomicroscopy for detection of narrow anterior chamber angles.
abstract: OBJECTIVE
  To assess the accuracy of classification of narrow anterior chamber (AC) angles using quantitative imaging by optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM).
  
  
  METHODS
  Observational comparative study.
  
  
  METHODS
  A high-speed (4000 axial scans/s) anterior segment OCT prototype was developed using a 1.3-microm light source. Seventeen normal subjects (17 eyes) and 7 subjects (14 eyes) with narrow angle glaucoma were enrolled. All subjects underwent gonioscopy, OCT, and UBM. Quantitative AC angle parameters (angle opening distance, angle recess area, and the trabecular-iris space area [a new parameter we have defined]) were measured from OCT and UBM images using proprietary processing software.
  
  
  METHODS
  Specificity and sensitivity in identifying narrow angles with image-derived AC angle parameters.
  
  
  RESULTS
  Eight of 31 eyes were classified as having narrow angles (Shaffer grade < or =1 in all quadrants). The AC angle parameters measured by both OCT and UBM had similar mean values, reproducibility, and sensitivity-specificity profiles. Both OCT and UBM showed excellent performance in identifying eyes with narrow angles. Areas under the receiver operating characteristic curves for these parameters were all in the range of 0.96 to 0.98.
  
  
  CONCLUSIONS
  Optical coherence tomography was similar to UBM in quantitative AC angle measurement and detection of narrow angles. In addition, it was easier to use and did not require contact with the eye. Optical coherence tomography is a promising method for screening individuals at risk for narrow angle glaucoma.
authors.affiliation: Cole Eye Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
authors.forename: Sunita
authors.initials: S
authors.lastname: Radhakrishnan
authors.forename: Jason
authors.initials: J
authors.lastname: Goldsmith
authors.forename: David
authors.initials: D
authors.lastname: Huang
authors.forename: Volker
authors.initials: V
authors.lastname: Westphal
authors.forename: David K
authors.initials: DK
authors.lastname: Dueker
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Rollins
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Izatt
authors.forename: Scott D
authors.initials: SD
authors.lastname: Smith
mesh_terms: D000328:Adult; D000867:Anterior Chamber / Q000473:pathology*; D019540:Area Under Curve; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis*; D006068:Gonioscopy; D006801:Humans; D007498:Iris / Q000473:pathology; D008297:Male; D033401:Microscopy, Acoustic / Q000379:methods*; D012372:ROC Curve; D015203:Reproducibility of Results; D012590:Sclera / Q000473:pathology; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*; D014129:Trabecular Meshwork / Q000473:pathology*