title: Comparison of Intraocular Pressure Measurements between Icare Pro Rebound Tonometer and Tono-Pen XL Tonometer in Supine and Lateral Decubitus Body Positions.
abstract: OBJECTIVE
  To compare intraocular pressure (IOP) measurements obtained using the Icare Pro rebound tonometer and Tono-Pen XL tonometer in supine and lateral decubitus body positions.
  
  
  METHODS
  One-hundred eyes of 50 subjects (normal volunteers or glaucoma suspects) were enrolled in this prospective observational study. IOP was measured in both eyes using the Icare Pro and Tono-Pen XL in the sitting position and the recumbent positions including supine, right lateral decubitus and left lateral decubitus. IOP was measured five minutes after assuming each of the recumbent postures in a randomized sequence. The eye on the lower side in the lateral decubitus position was termed as the dependent eye. Agreement of IOP readings between the Icare Pro and Tono-Pen was assessed in all recumbent positions. Differences of IOP readings (ΔIOP) between the two tonometers and their correlations with ocular parameters were also assessed in all positions.
  
  
  RESULTS
  The IOP readings obtained using Icare Pro and Tono-Pen showed good correlations in supine and lateral decubitus positions (all r > 0.7, p < 0.005), although Icare Pro readings were higher than Tono-Pen readings (all p < 0.001) in all positions. The ΔIOP showed a weakly positive correlation with central corneal thickness in both eyes, whereas such a positive correlation was found only in the dependent eye in the lateral decubitus positions (r = 0.307-0.531, all p < 0.005). Both the spherical equivalents and axial lengths were not correlated with ΔIOP in all positions.
  
  
  CONCLUSIONS
  IOP readings obtained with Tono-Pen and Icare Pro tonometers showed good agreement in supine as well as in lateral decubitus positions, although Icare readings were higher than Tono-Pen readings in all positions. Such differences in IOP readings between the different tonometers need to be considered when measuring IOPs in various body positions.
authors.affiliation: Department of Ophthalmology, Korea University College of Medicine , Seoul , Korea and.
authors.forename: Tae-Eun
authors.initials: TE
authors.lastname: Lee
authors.forename: Chungkwon
authors.initials: C
authors.lastname: Yoo
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Hwang
authors.forename: Shan
authors.initials: S
authors.lastname: Lin
authors.forename: Yong Yeon
authors.initials: YY
authors.lastname: Kim
mesh_terms: D000328:Adult; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011187:Posture; D011446:Prospective Studies; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation*; D055815:Young Adult
keywords: Body position; Icare tonometer; intraocular pressure; lateral decubitus; rebound tonometer; supine; tono-pen tonometer