title: Comparison of very-high-frequency ultrasound and spectral-domain optical coherence tomography corneal and epithelial thickness maps.
abstract: OBJECTIVE
  To compare corneal thickness and epithelial thickness measurements in maps obtained using the RTVue spectral domain optical coherence tomography (SD-OCT) system and the Artemis 2 immersion arc-scanning very-high-frequency ultrasound (VHF-US) system.
  
  
  METHODS
  Department of Ophthalmology, Columbia University Medical Center, New York, New York, USA.
  
  
  METHODS
  Comparative study.
  
  
  METHODS
  Eyes of normal volunteers were scanned with the SD-OCT system followed by the VHF-US system and then again by the SD-OCT system. On each map, the minimum corneal thickness and mean values of corneal thickness and epithelial thickness in the 3.0 mm radius zone and in 0.5 mm wide concentric annuli of up to a 3.0 mm radius around the corneal vertex were determined.
  
  
  RESULTS
  Both eyes of 12 normal volunteers were scanned. The corneal thickness values from both devices were highly correlated (R > 0.96); in the 3.0 mm radius zone, they were not statistically significantly different. There was no statistically significant change in epithelial thickness or corneal thickness in SD-OCT measurements taken before versus after immersion US. Although highly correlated (R > 0.76), the SD-OCT epithelial thickness values were systematically thinner (1.7 ± 2.1 μm) than the VHF-US measurements in the 3.0 mm radius zone (P < .01).
  
  
  CONCLUSIONS
  The corneal thickness measurements in the 3.0 mm radius zone in normal eyes were equivalent between the 2 systems. Although correlated, the VHF-US epithelial thickness measurements were systemically thicker than the SD-OCT values.
  
  
  BACKGROUND
  Drs. Silverman and Reinstein have a commercial interest in Arcscan, Inc. Dr. Reinstein is a consultant to Carl Zeiss Meditec. None of the other authors has a financial or proprietary interest in any material or method presented.
authors.affiliation: From the Department of Ophthalmology (Urs, Lloyd, Reinstein, Silverman), Columbia University Medical Center, and F.L. Lizzi Center for Biomedical Engineering (Silverman), Riverside Research, New York, New York, USA; London Vision Clinic (Reinstein), London, United Kingdom; Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France. Electronic address: ru2118@cumc.columbia.edu.
authors.forename: Raksha
authors.initials: R
authors.lastname: Urs
authors.affiliation: From the Department of Ophthalmology (Urs, Lloyd, Reinstein, Silverman), Columbia University Medical Center, and F.L. Lizzi Center for Biomedical Engineering (Silverman), Riverside Research, New York, New York, USA; London Vision Clinic (Reinstein), London, United Kingdom; Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France.
authors.forename: Harriet O
authors.initials: HO
authors.lastname: Lloyd
authors.affiliation: From the Department of Ophthalmology (Urs, Lloyd, Reinstein, Silverman), Columbia University Medical Center, and F.L. Lizzi Center for Biomedical Engineering (Silverman), Riverside Research, New York, New York, USA; London Vision Clinic (Reinstein), London, United Kingdom; Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France.
authors.forename: Dan Z
authors.initials: DZ
authors.lastname: Reinstein
authors.affiliation: From the Department of Ophthalmology (Urs, Lloyd, Reinstein, Silverman), Columbia University Medical Center, and F.L. Lizzi Center for Biomedical Engineering (Silverman), Riverside Research, New York, New York, USA; London Vision Clinic (Reinstein), London, United Kingdom; Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France.
authors.forename: Ronald H
authors.initials: RH
authors.lastname: Silverman
mesh_terms: D000328:Adult; D001699:Biometry / Q000295:instrumentation*; D003315:Cornea / Q000033:anatomy & histology*; D063171:Corneal Pachymetry; D019573:Epithelium, Corneal / Q000033:anatomy & histology*; D005260:Female; D064368:Healthy Volunteers; D019220:High-Energy Shock Waves; D006801:Humans; D008297:Male; D041623:Tomography, Optical Coherence / Q000295:instrumentation*; D014465:Ultrasonics / Q000295:instrumentation*