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Inter-optometrist variability of IOP measurement for modern tonometers and their agreement with Goldmann Applanation Tonometry

Campbell, P. ORCID: 0000-0002-6019-1596, Edgar, D. F ORCID: 0000-0001-9004-264X and Shah, R. ORCID: 0000-0002-6134-0936 (2021). Inter-optometrist variability of IOP measurement for modern tonometers and their agreement with Goldmann Applanation Tonometry. Clinical and Experimental Optometry, doi: 10.1080/08164622.2021.1878831

Abstract

Background: This study investigates: agreement in intraocular pressure measurements between three tonometers and Goldmann applanation tonometry (GAT); inter-optometrist agreement for each tonometer; intra-optometrist agreement for GAT; association between central corneal thickness (CCT) and IOP measurements with each tonometer.

Methods: IOP was measured using: CT-1P Non-Contact Tonometer (NCT) (Topcon Corporation, Tokyo, Japan), Pulsair IntelliPuff (Keeler Ltd., Windsor, UK) and Icare rebound tonometer (Icare, Helsinki, Finland) by two optometrists in a random order. Two GAT readings were obtained by each optometrist in a randomised masked manner. Mean differences, and 95% limits of agreement (LoA) for each measurement were calculated. CCT was measured by CT-1P pachymeter.

Results: Forty-one participants’ IOPs were measured. Mean differences (95% LoA) between NCT, Pulsair, Icare compared to GAT for one optometrist were: 0.8 (−5.4 to 6.9) mmHg, −1.7 (−8.2 to 4.8) mmHg, −1.6 (−9.0 to 5.9) mmHg. Mean differences (95% LoA) in inter-optometrist agreement for GAT, NCT, Pulsair and Icare were: 0.3 (−6.7 to 7.3) mmHg, 0.4 (−2.1 to 2.9) mmHg, −0.9 (−3.6 to 1.9) mmHg and −0.2 (−4.9 to 4.5) mmHg, respectively. Mean differences (95% LoA) for intra-optometrist agreement for GAT were 0.2 (4.3 to −4.7) mmHg and 0.1 (3.6 to −3.9) mmHg for each optometrist, respectively. There was a weak positive association between CCT and both GAT (r2 = 0.11) and NCT (r2 = 0.12).

Conclusion: Pulsair and Icare may measure IOP lower than GAT. Mean differences for inter-optometrist agreement for all tonometers were < 1 mmHg; Pulsair showed a statistically significant difference. Intra-optometrist agreement for GAT was good. IOP measurements taken by two community optometrists are comparable using tonometers used in community practice.

Publication Type: Article
Additional Information: This is the peer reviewed version of the following article: Peter Campbell, David F Edgar & Rakhee Shah (2021) Inter-optometrist variability of IOP measurement for modern tonometers and their agreement with Goldmann Applanation Tonometry, Clinical and Experimental Optometry, which has been published in final form at https://doi.org/10.1080/08164622.2021.1878831. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Publisher Keywords: Comparison, intraocular pressure, optometry, tonometer
Subjects: R Medicine > RE Ophthalmology
Departments: School of Health Sciences > Optometry & Visual Science
Date Deposited: 05 Mar 2021 09:01
URI: https://openaccess.city.ac.uk/id/eprint/25751
[img] Text - Accepted Version
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