Article Text

Download PDFPDF
Interobserver agreement using Goldmann applanation tonometry and dynamic contour tonometry: comparing ophthalmologists, nurses and technicians
  1. Aachal Kotecha1,2,
  2. Ahmed Elkarmouty1,
  3. Csilla Ajtony1,
  4. Keith Barton1,2,3
  1. 1Glaucoma Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
  2. 2NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology and Moorfields Eye Hospital NHS Foundation Trust, London, UK
  3. 3Department of Epidemiology and Genetics, UCL Institute of Ophthalmology, London, UK
  1. Correspondence to Dr Aachal Kotecha, NIHR BRC for Ophthalmology, Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; Aachal.kotecha{at}{at}


Purpose To compare agreement between ophthalmologists and non-ophthalmologists (nurses and ophthalmic technicians) when measuring the intraocular pressure (IOP) using Goldmann applanation tonometry (GAT) and Pascal dynamic contour tonometry (DCT).

Methods Patients attending for their routine glaucoma outpatient appointment were invited to participate. IOP was measured in one eye by either two ophthalmologists (observer group 1), two non-ophthalmologists (observer group 2) or one ophthalmologist and one non-ophthalmologist (observer group 3). All were experienced in using GAT and some experienced in using the DCT. The order of tonometer and staff was randomised. Agreement was calculated by Bland–Altman analysis, with the mean difference and 95% limits of agreement (LoA) of measurements calculated for each observer group.

Results One hundred eyes were measured within each observer group. The mean difference (95% LoA) in IOP measurements were GAT: group 1=−0.20 (4.9) mm Hg, group 2=0.6 (5.4) mm Hg and group 3=0.0 (3.7) mm Hg; DCT: group 1=0.8 (7.7) mm Hg, group 2=0.3 (4.2) and group 3=0.0 (5.2) mm Hg. The DCT consistently over-read the GAT for all observer groups.

Discussion/conclusions Ophthalmologists show good levels of agreement with each other when using GAT, while technicians/nursing staff show better agreement when using the DCT. The DCT may be a better tonometer to use if permanently delegating IOP measurements to non-ophthalmologists, but measurements cannot be interchanged with the GAT.

  • Intraocular pressure
  • Glaucoma

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Linked Articles

  • At a glance
    Keith Barton James Chodosh Jost Jonas