Accuracy of Perkins applanation tonometry and pneumatonometry in infants and children. A manometric study in vivo

B. Sherman, D. Eisenberg, J. Mullen, J. Ramsey, J. Schuman, C. McKeown

Research output: Contribution to journalArticlepeer-review


Purpose: A discrepancy in the measured value of intraocular pressure (IOP) between the Perkins applanation tonometer (TA) and the pneumatonometer (TP) is well documented. This is a pilot study of ongoing work with two goals: 1) to reconfirm this discrepancy, 2) if present, to determine which instrument more closely matches the true IOP determined by manometry. Methods: Informed consent was obtained from all patients. Patients were eligible for this study if they met the following conditions: age less than twelve years, a planned intraocular procedure requiring an intracameral infusion cannula, and general anesthesia. After general anesthesia was induced the patient was prepped and draped and, with the aid of an operating microscope, a cannula was inserted into the anterior chamber of the eye. Continuous manometric readings of IOP were obtained with adjustment of the IOP from 10 to 35 mmHg by altering the bottle height of the infusing Balanced Salt Solution. Both TA and TP measurements were obtained along with simultaneous manometry readings. Results: In the one eye studied to date, the average difference between TA and manometry was 9.9 ± 1.2 (mean ± standard error in mmHg), and the average difference between TP and manometry was 1.2 ± 1.6 (p <0.01). Conclusion: This pilot study agrees with previous reports of TA reading less than TP in infants and children. These data suggest that TP may be more accurate.

Original languageEnglish (US)
Pages (from-to)S815
JournalInvestigative Ophthalmology and Visual Science
Issue number3
StatePublished - Feb 15 1996

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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