Campbell, P.

Edgar, D. F

Shah, R.

English

City Research Online

              City, University of London Institutional RepositoryCitation: Campbell, P., Edgar, D. F and Shah, R. ORCID: 0000-0002-6134-0936 (2019). Agreement of three tonometers with Goldmann Applanation Tonometry (GAT). Investigative Ophthalmology & Visual Science, 60(9), This is the presentation version of the paper. This version of the publication may differ from the final published version. Permanent repository link:  http://openaccess.city.ac.uk/id/eprint/23268/Link to published version: Copyright and reuse: City Research Online aims to make research outputs of City, University of London available to a wider audience. Copyright and Moral Rights remain with the author(s) and/or copyright holders. URLs from City Research Online may be freely distributed and linked to.City Research Online:            http://openaccess.city.ac.uk/            publications@city.ac.ukCity Research OnlineConclusions• For three tonometers commonly used by UK community/primary care optometrists we found over half of measurements were within ±2mmHg of GAT, with NCT having the greatest percentage of measurements within +-2mmHg. These findings concur with previous studies.4• Pulsair and Icare recorded mean IOP lower than GAT, and there was a statistically significant difference between mean IOPs for Pulsairvs GAT. Both these devices had wider 95% LoA than NCT. • Our results agreed with other researchers who found Icare to underestimate IOP7 more so when GAT ≥ 23mmHg.8• Further work is needed to investigate the clinical impact of the choice of tonometer used in the detection of patients at risk of glaucoma, although IOP alone is not a good indicator of glaucoma.9References1.NICE. Glaucoma: diagnosis and management | Guidance and guidelines | NICE. (2017). Available at: https://www.nice.org.uk/Guidance/NG81/evidence. (Accessed: 15 December 2018)2.Bowling, B., Chen, S. D. M. & Salmon, J. F. Outcomes of referrals by community optometrists to a hospital glaucoma service. Br. J. Ophthalmol. 89, 1102–1104 (2005).3.Heijl, A. et al. Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial. Arch. Ophthalmol. 120, 1268–1279 (2002).4.Cook, J. A. et al. Systematic review of the agreement of tonometers with Goldmann applanation tonometry. Ophthalmology 119, 1552–1557 (2012).5. Myint J, Edgar DF, Kotecha A, Murdoch IE, Lawrenson JG. A national survey of diagnostic tests reported by UK community optometrists for the detection of chronic open angle glaucoma. Ophthalmic and Physiological Optics. 2011 Jul;31(4):353-9.6. Dabasia PL, Edgar DF, Garway‐Heath DF, Lawrenson JG. A survey of current and anticipated use of standard and specialist equipment by UK optometrists. Ophthalmic and Physiological Optics. 2014 Sep;34(5):592-613.7. Rosentreter, A. et al. Rebound, Applanation, and Dynamic Contour Tonometry in Pathologic Corneas. Cornea 32, 313 (2013).8. Gao, F., Liu, X., Zhao, Q. & Pan, Y. Comparison of the iCare rebound tonometer and the Goldmann applanation tonometer. Exp. Ther. Med. 13, 1912–1916 (2017).9  Chan, M. P. Y. et al. Glaucoma and intraocular pressure in EPIC-Norfolk Eye Study: cross sectional study. BMJ 358, j3889 (2017).• Agreement between NCT, Pulsair, Icare and GAT was assessed using Bland–Altman difference analysis, and mean differences and 95% limits of agreement (LoA) of measurements calculated. • Percentages of IOP readings within ±2mmHg of the GAT reading were obtained.Results• Forty-one participants had their IOP measured by all four tonometers: median age 36 years (IQR: 20, 49), 71% female. • Figure 2 displays the Bland-Altman plots for each tonometer compared to GAT and the percentage of readings within ±2mmHg of GAT.• Table 1 outlines the results for each tonometer compared to GAT.Agreement of three Tonometers with Goldmann Applanation Tonometry Email: Peter.campbell@city.ac.ukPeter Campbell1,2, David F. Edgar1, Rakhee Shah11. Optometry and Visual Science, City, University of London, UK     2. Guy’s and St Thomas’ NHS Foundation Trust, London, UK @petercampbellc1Tonometer Mean (SD) IOP (mmHg)Mean Bias:Tonometer-GAT IOP (mmHg)95% LoA(mmHg)P value(F Test)GAT 17.1 (3.7) - -NCT 17.9 (3.2) 0.8 -5.4 to 6.9 0.21Pulsair 15.4 (2.6) -1.7 -8.2 to 4.8 0.01Icare 15.6 (4.2) -1.6 -9.0 to 5.9 0.22Figure 2: Bland–Altman difference plots and % Agreement for NCT, Pulsair and Icare compared to GATTable 1 Comparison of each tonometer to GAT (95% LoA: Limits of Agreement)2421 - A0585 Introduction• Cases of glaucoma in the UK are mostly identified through routine examinations by community/primary care optometrists.1,2• Elevated Intraocular Pressure (IOP) is an important risk factor for glaucoma.3• Goldmann Applanation Tonometry (GAT) is regarded as the reference method for IOP measurement.4• UK community optometrists principally use non-contact or rebound tonometry to measure IOP.5,6 Knowledge of how these devices agree with GAT would help inform their choice of tonometer and potentially reduce the number of false positive referrals.Purpose• To assess the agreement of three tonometers commonly used by UK community optometrists with GAT. Methods• Participants, 18 years and over, were recruited from a university eye clinic.• IOP was measured by two research optometrists (RO1 and RO2), both experienced in GAT.• IOP was first measured on the randomly selected study eye (SE1) using the three tonometers, NCT, Pulsair and Icare (Figure 1) by RO1. • GAT readings were then obtained in a masked manner by RO1. The force on the probe was initially set at a randomly selected value between 1g and 2g by RO2; RO1, masked to the dial reading, adjusted the probe until the end point, and RO2 recorded the measurement. Figure 1: Tonometers assessed for their agreement with GAT A: CT-1P Non-Contact Tonometer (NCT) (Topcon, Topcon Corporation, Tokyo, Japan). B: Pulsair IntelliPuff (Keeler Ltd., Windsor, UK). C: Icare rebound tonometer (Icare®, Helsinki, Finland).A B CAcknowledgementsThis project is supported by a Pump Priming Funding – City, University of London.54%54%56%40% 45% 50% 55% 60%IcarePulsairNCTAGREEMENT WITHIN ±2MMHG OF GAT

Agreement of three tonometers with Goldmann Applanation Tonometry (GAT)

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Agreement of three tonometers with Goldmann Applanation Tonometry (GAT)

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