title: Tonometry in adults and children. A manometric evaluation of pneumatonometry, applanation, and TonoPen in vitro and in vivo.
abstract: OBJECTIVE
  The purpose of the study was to determine the accuracy of applanation tonometry, pneumatonometry, and TonoPen tonometry in adults and children and the effect of age on tonometer error.
  
  
  METHODS
  The design was divided into four parts: part 1 was prospective and cross-sectional, and parts 2 through 4 were prospective, cross-sectional, and masked.
  
  
  METHODS
  This study contained 72 patients representing 74 data points.
  
  
  METHODS
  Tonometry with simultaneous manometry was performed.
  
  
  METHODS
  Intraocular pressure (i.o.p.) and the tonometric estimate of IOP were obtained.
  
  
  RESULTS
  The normal pediatric IOP follows the line Ta = 0.71 age(years) + 10 up to age 10. Applanation tonometry under anesthesia differs from pneumatonometry by an average of -8.6 mmHg and is age related by the equation Ta = Tpn + 2.6 log(age) - 10.3. The TonoPen was the most accurate instrument for enucleated eyes, and the pneumatonometer was the most accurate in anesthetized living eyes.
  
  
  CONCLUSIONS
  Applanation tonometry markedly underestimated IOP in young eyes. TonoPen tonometry performed well with enucleated eyes but was not adequately accurate for clinical use. The pneumatonometer performed the best clinically and the best overall.
authors.affiliation: New England Eye Center, Tufts University School of Medicine, Boston, Massachusetts, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Eisenberg
authors.forename: B G
authors.initials: BG
authors.lastname: Sherman
authors.forename: C A
authors.initials: CA
authors.lastname: McKeown
authors.forename: J S
authors.initials: JS
authors.lastname: Schuman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008365:Manometry / Q000379:methods; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation / Q000592:standards*