title: A clinical evaluation of proview pressure phosphene tonometry in children.
abstract: OBJECTIVE
  The Proview tonometer measures intraocular pressure by inducing a pressure phosphene through the eyelid and, if reliable and valid, may offer a quick, nonthreatening and noninvasive alternative method of obtaining intraocular pressures (IOPs) without the use of eye drops. This study compares the IOP measurements obtained in children using Proview pressure phosphene tonometry (PPPT) and Goldmann tonometry (GT).
  
  
  METHODS
  One hundred four 5- to 12-year-old patients of the University Optometric Center/SUNY College of Optometry participated in the study. Subjects were randomized to receive, by different investigators, either PPPT or GT first. Two measurements with each instrument were attempted on each eye of all subjects. A subgroup of 41 subjects was asked which of the two methods was preferred.
  
  
  RESULTS
  Seven percent of the subjects did not report a pressure phosphene response compared with 12% of the subjects on whom the investigators were unable to perform GT. The remaining 85 subjects completed the subject protocol. Of the 41 subjects asked, 56% preferred PPPT, 24% had no preference, and 20% preferred GT. The coefficient of repeatability between the two readings was higher for PPPT (3-4 mm Hg) than for GT (1 mm Hg). Mean IOP was 4 mm Hg higher for PPPT than GT with the difference in readings between the two instruments increasing with higher IOPs (r >19%, p < 0.005).
  
  
  CONCLUSIONS
  In our study of healthy young subjects, PPPT measurements of IOP appear to be repeatable within a few millimeters of mercury in most children, but for some children, variability in repeat measurements can be substantial. Our data showed a mean difference in readings of 4 mm Hg with a 95% confidence interval that the PPPT reading was between 12 mm Hg above GT and 4 mm Hg below GT. This wide range of values indicates that PPPT is not comparable to GT. However, because our study found that children can appreciate pressure phosphenes and most prefer PPPT over GT, the Proview monitor may have value as a noninvasive, portable screener in pediatric patients. To fully evaluate this potential, further studies are needed that include patients with high IOPs.
authors.affiliation: Department of Clinical Sciences, State University of New York, State College of Optometry, New York, New York, USA.
authors.forename: Ida
authors.initials: I
authors.lastname: Chung
authors.forename: Amelia
authors.initials: A
authors.lastname: Bartolone
authors.forename: William H
authors.initials: WH
authors.lastname: Swanson
authors.forename: Andrea P
authors.initials: AP
authors.lastname: Thau
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D005901:Glaucoma / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D010719:Phosphenes; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000379:methods*