title: Intraocular pressure in children: the effect of body position as assessed by Icare and Tono-Pen tonometers.
abstract: OBJECTIVE
  To explore the effect of body position (sitting vs supine) on intraocular pressure (IOP) in children, as assessed by the Icare PRO and the Tono-Pen.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Children with known or suspected glaucoma and those without glaucoma were recruited from the Duke Eye Center pediatric clinic. Subjects underwent tonometry in both eyes while upright (sitting), after instillation of topical anesthetic, with either the Icare PRO or the Tono-Pen first, and then the second instrument (order randomized). Goldmann applanation tonometry (GAT) was then performed by a clinician masked to the previous measurements. The subjects were then placed in the supine position for 5 minutes, and tonometry using the Icare PRO and the Tono-Pen was obtained, in the same order used when they were the sitting position.
  
  
  RESULTS
  Enrolled were 47 children (94 eyes). Mean seated IOP for GAT, Icare PRO and Tono-Pen were 16.4 ± 4.2, 17.5 ± 3.5, and 18.0 ± 3.9 mm Hg, respectively. The mean supine IOP for the Icare PRO and Tono-Pen were 18.4 ± 4.5 and 18.8 ± 4.2 mm Hg, respectively. This rise was +0.9 ± 2.3 mm Hg for Icare PRO (P = 0.01) and +0.7 ± 1.8 mm Hg for Tono-Pen (P = 0.009), respectively.
  
  
  CONCLUSIONS
  In children, Icare PRO tonometry correlates well with GAT in the sitting position, and with the Tono-Pen in both the sitting and supine positions. IOP rises when a child changes position from sitting to supine when measured by the Icare PRO or the Tono-Pen. However, the increase, which is less than 1 mm Hg, seems clinically insignificant and is unlikely to alter glaucoma management in children.
authors.affiliation: Abrahamson Pediatric Eye Institute, Cincinnati Children's Hospital Medical Center, Department of Ophthalmology, University of Cincinnati, College of Medicine, Cincinnati, Ohio, USA.
authors.forename: Eniolami O
authors.initials: EO
authors.lastname: Dosunmu
authors.affiliation: Virginia Eye Institute, Richmond, Virginia, USA.
authors.forename: Inna
authors.initials: I
authors.lastname: Marcus
authors.affiliation: Department of Ophthalmology, University of Texas Medical Branch in Galveston, Galveston, Texas, USA.
authors.forename: Irene
authors.initials: I
authors.lastname: Tung
authors.affiliation: Department of Ophthalmology Lerdsin Hospital, Medical Bureau Ministry of Public Health, Bangkok, Thailand.
authors.forename: Warakorn
authors.initials: W
authors.lastname: Thiamthat
authors.affiliation: Duke Eye Center, Durham, North Carolina, USA. Electronic address: Freed003@mc.duke.edu.
authors.forename: Sharon F
authors.initials: SF
authors.lastname: Freedman
mesh_terms: D000293:Adolescent; D002648:Child; D004311:Double-Blind Method; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D009798:Ocular Hypertension / Q000175:diagnosis; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation*