title: Non-invasive measurement of intraocular pressure by near-infrared spectroscopy.
abstract: OBJECTIVE
  To assess a new non-contact method for non-invasive measurement of intraocular pressure (IOP) using near-infrared spectroscopy.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Eleven porcine eyes were cannulated into the anterior chamber by a needle connected with a water column. Measuring the near-infrared spectrum in diffuse reflectance out of the anterior chamber by near-infrared spectroscopy, IOP was determined and compared with the height of the water column which was varied between 0 cm and 100 cm.
  
  
  RESULTS
  In total, 363 near-infrared spectrometric measurement values were obtained. Correlating the near-infrared spectrometric measurements with the height of the water column showed a relationship with a correlation coefficient of r(2) = .858 and a steepness of the regression line of .96.
  
  
  CONCLUSIONS
  The results of the present pilot study suggest that near-infrared spectrometric tonometry may present a new technology for non-invasive and non-contact IOP measurement.
authors.affiliation: Mannheim University of Applied Sciences, Institute for Instrumental Analysis, Mannheim, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Weissbrodt
authors.forename: Ralf
authors.initials: R
authors.lastname: Müeller
authors.forename: Juergen
authors.initials: J
authors.lastname: Backhaus
authors.forename: Jost B
authors.initials: JB
authors.lastname: Jonas
mesh_terms: D000818:Animals; D007429:Intraocular Pressure; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013552:Swine; D014065:Tonometry, Ocular / Q000379:methods*