Evidence Table 1Diagnostic accuracy of non-contact tonometry vs. Goldmann contact tonometry

Study detailsPatientsDiagnostic toolsMeasure of DisordersResultsComments
Atkinson et al, 19925

Study design:
Diagnostic

Evidence level:
II
Patient group:
Patients from general ophthalmology outpatients departments and glaucoma clinics across 3 UK centres. (type of glaucoma not specified)

Exclusion criteria:
Uncooperative patients or those with scarred corneas

All patients
N: 403 eyes
Age (median): NR
M/F: NR
Drop outs: NR
Assessment tool under investigation:
Pulse air non-contact tonometry* measured before Goldmann tonometry.

Three different machines:
  • Machines A and B (same hospital) used at least 3 readings until 3 readings lay within 5mmHg of each other
  • Machine C (different centre) used 4 successive readings. If any reading >30mmHg a further set was taken with machine set to 30+ mode.
Gold standard:
Goldmann applanation tonometry (GAT) (calibrated Haag-Streit AG Goldmann tonometer.
  • Measured within 3 minutes of pulse air reading. Patients did not move from position between measurement and instillation of oxybuprocaine 0.4% & fluorescein.
Machine A (64 eyes) †Funding:
Not reported

Limitations:
Number of eyes were recruited was reported but not the number of patients. Does not report the proportion of patients with glaucoma or ocular hypertension.

Also reported: mean (SD) IOP, and correlation coefficient (r) and linear regression equation (between two; mean (SD) differences in IOP between type of tonometer;

Additional Notes:
(ability to detect a Goldmann IOP >21mmHg)

Observer masked

* Study presented as 3 studies, 3 machines used in two centres
Sensitivity81%
Specificity93%
Positive predictive value85%
Negative predictive value93%
Prevalence31%
Positive Likelihood Ratio12.47
Negative Likelihood Ratio0.16
Pre-test odds0.45
Post-Test Odds (Probability) +ve result5.67 (85%)
Post-Test Probability −ve result5.28 (84%)
Machine B (223 eyes) †
Sensitivity40%
Specificity95%
Positive predictive value84%
Negative predictive value71%
Prevalence40%
Positive Likelihood Ratio8.1
Negative Likelihood Ratio0.63
Pre-test odds0.65
Post-Test Odds (Probability) +ve result5.29 (84%)
Post-Test Probability −ve result1.34 (57%)
Machine C (116 eyes) †
Sensitivity48%
Specificity94%
Positive predictive value63%
Negative predictive value89%
Prevalence18%
Positive Likelihood Ratio7.54
Negative Likelihood Ratio0.56
Pre-test odds0.22
Post-Test Odds (Probability) +ve result1.67 (63%)
Post-Test Probability −ve result1.12 (53%)

Abbreviations: NR=not reported, M/F=male/female, NA=not applicable, Sig=statistically significant at 5%, N=total number of patients randomised, CI95%= 95% Confidence Interval

From: Appendix D, Evidence tables

Cover of Glaucoma
Glaucoma: Diagnosis and Management of Chronic Open Angle Glaucoma and Ocular Hypertension.
NICE Clinical Guidelines, No. 85.
National Collaborating Centre for Acute Care (UK).
Copyright © 2009, National Collaborating Centre for Acute Care.

Apart from any fair dealing for the purposes of research or private study, criticism or review, as permitted under the Copyright, Designs and Patents Act, 1988, no part of this publication may be reproduced, stored or transmitted in any form or by any means, without the prior written permission of the publisher or, in the case of reprographic reproduction, in accordance with the terms of licences issued by the Copyright Licensing Agency in the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publisher at the UK address printed on this page.

The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant laws and regulations and therefore for general use.

The rights of National Collaborating Centre for Acute Care to be identified as Author of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act, 1988.

PubMed Health. A service of the National Library of Medicine, National Institutes of Health.