title: Cup-to-Disc Ratio From Heidelberg Retina Tomograph 3 and High-Definition Optical Coherence Tomography Agrees Poorly With Clinical Assessment.
abstract: OBJECTIVE
  To investigate the agreement of vertical cup-to-disc ratio (VCDR) measured from Heidelberg Retina Tomograph 3 (HRT-3), high-definition optical coherence tomography (HD-OCT), and clinical grading.
  
  
  METHODS
  A total of 933 consecutive subjects underwent optic nerve head imaging with HRT-3 and HD-OCT during a single visit. The vertical dimensions of the disc and cup were measured by slit-lamp examination using an eyepiece graticule. Bland-Altman plots evaluated the agreement in the VCDR obtained by the 2 instruments and clinical grading.
  
  
  RESULTS
  We found a significant trend for the difference in VCDR measured clinically and with HRT and HD-OCT (P<0.001 for both). The mean VCDR differed significantly between clinical measurement and that evaluated by HRT and HD-OCT, respectively (0.40 ± 0.12 vs. 0.37 ± 0.21 and 0.40 ± 0.12 vs. 0.50 ± 0.14, P<0.001 for both), with significantly poor correlation (r(2)=0.35 and 0.34, P<0.001 for both).
  
  
  CONCLUSIONS
  In general, there is poor correlation and a lack of agreement of VCDR measured using HRT-3, HD-OCT, and clinical grading. HD-OCT has somewhat better agreement with clinical measurements of VCDR. Compared with clinical grading, HD-OCT tended to overestimate VCDR, whereas HRT-3 tended to underestimate it.
authors.affiliation: *Singapore Eye Research Institute & Singapore National Eye Center †Duke-NUS Graduate Medical School ‡Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Shamira A
authors.initials: SA
authors.lastname: Perera
authors.forename: Li Lian
authors.initials: LL
authors.lastname: Foo
authors.forename: Carol Y L
authors.initials: CY
authors.lastname: Cheung
authors.forename: John C
authors.initials: JC
authors.lastname: Allen
authors.forename: Daniel
authors.initials: D
authors.lastname: Chua
authors.forename: Yih Chung
authors.initials: YC
authors.lastname: Tham
authors.forename: Seng Chee
authors.initials: SC
authors.lastname: Loon
authors.forename: Tien Yin
authors.initials: TY
authors.lastname: Wong
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005901:Glaucoma / Q000175:diagnosis; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy / Q000379:methods; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D012029:Refraction, Ocular / Q000502:physiology; D015203:Reproducibility of Results; D066167:Slit Lamp; D041623:Tomography, Optical Coherence / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed; D014792:Visual Acuity / Q000502:physiology