title: Comparison of corneal power, astigmatism, and wavefront aberration measurements obtained by a point-source color light-emitting diode-based topographer, a Placido-disk topographer, and a combined Placido and dual Scheimpflug device.
abstract: OBJECTIVE
  To evaluate and compare the performance of a point-source color light-emitting diode (LED)-based topographer (color-LED) in measuring anterior corneal power and aberrations with that of a Placido-disk topographer and a combined Placido and dual Scheimpflug device.
  
  
  METHODS
  Cullen Eye Institute, Baylor College of Medicine, Houston, Texas USA.
  
  
  METHODS
  Retrospective observational case series.
  
  
  METHODS
  Normal eyes and post-refractive-surgery eyes were consecutively measured using color-LED, Placido, and dual-Scheimpflug devices. The main outcome measures were anterior corneal power, astigmatism, and higher-order aberrations (HOAs) (6.0 mm pupil), which were compared using the t test.
  
  
  RESULTS
  There were no statistically significant differences in corneal power measurements in normal and post-refractive surgery eyes and in astigmatism magnitude in post-refractive surgery eyes between the color-LED device and Placido or dual Scheimpflug devices (all P > .05). In normal eyes, there were no statistically significant differences in 3rd-order coma and 4th-order spherical aberration between the color-LED and Placido devices and in HOA root mean square, 3rd-order coma, 3rd-order trefoil, 4th-order spherical aberration, and 4th-order secondary astigmatism between the color-LED and dual Scheimpflug devices (all P > .05). In post-refractive surgery eyes, the color-LED device agreed with the Placido and dual-Scheimpflug devices regarding 3rd-order coma and 4th-order spherical aberration (all P > .05).
  
  
  CONCLUSIONS
  In normal and post-refractive surgery eyes, all 3 devices were comparable with respect to corneal power. The agreement in corneal aberrations varied.
  
  
  BACKGROUND
  Drs. Wang, Koch, and Weikert are consultants to Ziemer Ophthalmic Systems AG. Dr. Koch is a consultant to Abbott Medical Optics, Inc., Alcon Surgical, Inc., and i-Optics Corp.
authors.affiliation: From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil. Electronic address: brunaventuramd@gmail.com.
authors.forename: Bruna V
authors.initials: BV
authors.lastname: Ventura
authors.affiliation: From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Shazia F
authors.initials: SF
authors.lastname: Ali
authors.affiliation: From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Koch
authors.affiliation: From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Mitchell P
authors.initials: MP
authors.lastname: Weikert
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000175:diagnosis* / Q000503:physiopathology; D003315:Cornea / Q000502:physiology*; D019781:Corneal Topography / Q000295:instrumentation*; D057108:Corneal Wavefront Aberration / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography / Q000295:instrumentation; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies