title: Comparison of Visante and slit-lamp anterior segment optical coherence tomography in imaging the anterior chamber angle.
abstract: OBJECTIVE
  To compare the diagnostic performance of two anterior segment optical coherence tomography (AS-OCT) devices in assessing the anterior chamber angle (ACA).
  
  
  METHODS
  Visante-OCT and slit-lamp-OCT (SL-OCT) were performed on 101 patients by a single operator. The AS-OCT images were processed by customised 'dewarping' software and assessed by two glaucoma specialists masked to clinical findings. A closed ACA was defined by the presence of contact between the iris and angle anterior to the scleral spur. Measurements of the ACA, anterior chamber depth (ACD), and pupil diameter were analysed. Gonioscopy was performed by another examiner masked to AS-OCT findings.
  
  
  RESULTS
  Qualitative analysis could be carried out in 83 (83%) eyes and quantitative analysis in 61 (60%) eyes. A closed angle in at least one quadrant of the eye was observed in 30 eyes with gonioscopy; Visante-OCT imaging identified 29 of 30 (97%) and SL-OCT imaging identified 27 of 30 (90%) of these eyes (P=0.50, McNemar test). Visante-OCT detected more eyes with at least one closed quadrant than SL-OCT (55 vs46 eyes, respectively, P=0.01). Overall, SL-OCT had better agreement with gonioscopy than with Visante-OCT. Both AS-OCTs showed good agreement for ACD measurements; however, SL-OCT tended to provide consistently higher ACA measurements and smaller pupil diameters than did Visante-OCT.
  
  
  CONCLUSIONS
  Both AS-OCT devices detected most of the eyes with closed ACA on gonioscopy. However, Visante-OCT detected more closed ACAs than did SL-OCT. The better agreement between SL-OCT and gonioscopy is likely because of the use of visible light during both examinations. The ACA measurements obtained with each device are not interchangeable.
authors.affiliation: Singapore Eye Research Institute and Singapore National Eye Center, Singapore, Singapore.
authors.forename: L M
authors.initials: LM
authors.lastname: Sakata
authors.forename: T T L
authors.initials: TT
authors.lastname: Wong
authors.forename: H-T
authors.initials: HT
authors.lastname: Wong
authors.forename: R S
authors.initials: RS
authors.lastname: Kumar
authors.forename: H M
authors.initials: HM
authors.lastname: Htoon
authors.forename: H T
authors.initials: HT
authors.lastname: Aung
authors.forename: M
authors.initials: M
authors.lastname: He
authors.forename: T
authors.initials: T
authors.lastname: Aung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000033:anatomy & histology*; D005260:Female; D006068:Gonioscopy; D006801:Humans; D007498:Iris / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011680:Pupil / Q000502:physiology; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*