title: Prospective comparison of ultrasound biomicroscopy and anterior segment optical coherence tomography for evaluation of anterior chamber dimensions in European eyes with primary angle closure.
abstract: OBJECTIVE
  To compare the accuracy in measurement of the anterior chamber (AC) angle by anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in European patients with suspected primary angle closure (PACS), primary angle closure (PAC), or primary angle-closure glaucoma (PACG).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  In all, 55 eyes of 33 consecutive patients presenting with PACS, PAC, or PACG were examined with AS-OCT, followed by UBM. The trabecular-iris angle (TIA) was measured in all four quadrants. The angle-opening distance (AOD) was measured at 500 microm from the scleral spur. The Bland-Altman method was used for assessing agreement between the two methods.
  
  
  RESULTS
  The mean (+/-SD) superior TIA was 19.3+/-15.8 degrees in AS-OCT and 15.7+/-15.0 degrees in UBM (P=0.50) and inferior TIA was 17.9+/-12.9 degrees (AS-OCT) and 16.7+/-14.1 degrees (UBM) (P=0.71). The superior AOD(500) was 0.17+/-0.16 mm in UBM and 0.21+/-0.16 mm in AS-OCT (P=0.06). Bland-Altman analysis showed a mean SD of+/-9.4 degrees for superior and inferior TIA and a mean SD of +/-0.10 mm for superior and inferior AOD(500).
  
  
  CONCLUSIONS
  This comparative study shows that AS-OCT measurements are significantly correlated with UBM measurements but show poor agreement with each other. We do not believe that AS-OCT can replace UBM for the quantitative assessment of the AC angle.
authors.affiliation: Glaucoma Sectore, Department of Ophthalmology, University of Geneva, Geneva, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Mansouri
authors.forename: J
authors.initials: J
authors.lastname: Sommerhalder
authors.forename: T
authors.initials: T
authors.lastname: Shaarawy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000000981:diagnostic imaging / Q000473:pathology*; D003430:Cross-Sectional Studies; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000208:ethnology; D006801:Humans; D008297:Male; D033401:Microscopy, Acoustic / Q000379:methods*; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*; D014129:Trabecular Meshwork / Q000473:pathology; D044465:White People; D055815:Young Adult