title: Residual and Dynamic Range of Retinal Nerve Fiber Layer Thickness in Glaucoma: Comparison of Three OCT Platforms.
abstract: OBJECTIVE
  To estimate visual field (VF) sensitivity at which retinal nerve fiber layer (RNFL) thinning reaches the measurement floor and at which RNFL stops thinning (change points), the dynamic range of RNFL thickness, and the number of steps from normal to RNFL floor among three optical coherence tomography (OCT) devices.
  
  
  METHODS
  Glaucomatous patients (n = 58) and healthy subjects (n = 55-60) prospectively underwent VF testing and RNFL thickness measurement with Cirrus, Spectralis, and RTVue. Change points and corresponding RNFL thicknesses were estimated with simple linear regression (SLR) and Bayesian change point (BCP) analyses. The dynamic range and number of steps to RNFL floor were determined.
  
  
  RESULTS
  The average VF change points and corresponding residual thickness at the time RNFL stopped thinning were -22.2 dB and 57.0 μm (Cirrus), -25.3 dB and 49.2 μm (Spectralis), and -24.6 dB and 64.7 μm (RTVue). The RNFL dynamic ranges derived from SLR values were wider on Spectralis (52.6 μm) than on Cirrus (35.4 μm) and RTVue (35.5 μm); the corresponding number of steps to reach the RNFL floor were 9.0 on Cirrus, 10.6 on Spectralis, and 8.3 on RTVue.
  
  
  CONCLUSIONS
  The relative VF sensitivity at which average RNFL thickness reaches the measurement floor, the residual layer thickness, and RNFL dynamic measurement range differ among the three devices. However, the number of steps from normal to the RNFL thickness floor is comparable.
authors.affiliation: Department of Ophthalmology University of North Carolina, Chapel Hill, North Carolina, United States.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Mwanza
authors.affiliation: Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami, Miami, Florida, United States.
authors.forename: Hanna Y
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology University of North Carolina, Chapel Hill, North Carolina, United States.
authors.forename: Donald L
authors.initials: DL
authors.lastname: Budenz
authors.affiliation: Department of Biostatistics, Yale School of Public Health, Yale University, New Haven, Connecticut, United States.
authors.forename: Joshua L
authors.initials: JL
authors.lastname: Warren
authors.affiliation: Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami, Miami, Florida, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Margolis
authors.affiliation: Department of Ophthalmology University of North Carolina, Chapel Hill, North Carolina, United States.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Lawrence
authors.affiliation: Department of Ophthalmology University of North Carolina, Chapel Hill, North Carolina, United States.
authors.forename: Pooja D
authors.initials: PD
authors.lastname: Jani
authors.affiliation: Department of Ophthalmology University of North Carolina, Chapel Hill, North Carolina, United States.
authors.forename: Garrett S
authors.initials: GS
authors.lastname: Thompson
authors.affiliation: Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami, Miami, Florida, United States.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Lee
mesh_terms: D004867:Equipment Design; D005901:Glaucoma; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D057066:Low Tension Glaucoma / Q000175:diagnosis*; D009412:Nerve Fibers / Q000473:pathology*; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000295:instrumentation*