title: Transpalpebral measurement of intraocular pressure using the TGDc-01 tonometer versus standard Goldmann applanation tonometry.
abstract: BACKGROUND
  A recently developed digital tonometer for transpalpebral intraocular pressure (IOP) measurement, distributed by Corneal, Inc., allows the noninvasive measurement of IOP for screening purposes.
  
  
  METHODS
  We measured the IOP of 218 eyes in 109 patients of the Interdisciplinary Uveitis Center of the University of Heidelberg with intact corneal epithelium. IOPs were measured first with the TGDc-01 tonometer, and then by means of Goldmann tonometry. IOPs were recorded by two independent examiners. The mean of three measurements obtained with the TGDc-01 was taken, whereas only one measurement was performed with the Goldmann tonometer.
  
  
  RESULTS
  The mean difference between the TGDc-01 and Goldmann measurements was 3.7 mmHg. The standard deviation of the differences was +/-4.06 mmHg. Thus measurements acquired with the TGDc-01 may range 4.4 mmHg above or 11.8 mmHg below the values given by Goldmann tonometry.
  
  
  CONCLUSIONS
  The IOP values obtained with the TGDc-01 were in poor agreement with Goldmann tonometry. We found a higher variation as well as a bias towards lower IOP values with the TGDc-01. It is a question of clinical judgement as to how far these deviating measurements can be accepted for screening purposes. Because the IOPs obtained with the TGDc-01 are generally lower and less accurate than those obtained with the Goldmann tonometer we believe that the TGDc-01 is not a reliable tool for IOP measurement in clinical routine.
authors.affiliation: Interdisciplinary Uveitis Center, University of Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany. dr_annette_loesch@yahoo.de
authors.forename: Annette
authors.initials: A
authors.lastname: Lösch
authors.forename: Alexander
authors.initials: A
authors.lastname: Scheuerle
authors.forename: Volker
authors.initials: V
authors.lastname: Rupp
authors.forename: Gerd
authors.initials: G
authors.lastname: Auffarth
authors.forename: Matthias
authors.initials: M
authors.lastname: Becker
mesh_terms: D005143:Eyelids / Q000502:physiology; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008365:Manometry / Q000295:instrumentation / Q000379:methods*; D008875:Middle Aged