Original Research

A comparison of rebound and applanation tonometry in children with and without primary congenital glaucoma

Hester Kruger, Naseer Ally, Natasha Naidu, Ismail Mayet
African Vision and Eye Health | Vol 83, No 1 | a921 | DOI: https://doi.org/10.4102/aveh.v83i1.921 | © 2024 Hester Kruger, Naseer Ally, Natasha Naidu, Ismail Mayet | This work is licensed under CC Attribution 4.0
Submitted: 20 January 2024 | Published: 28 May 2024

About the author(s)

Hester Kruger, Department of Neurosciences, Faculty of Ophthalmology, University of the Witwatersrand, Johannesburg, South Africa
Naseer Ally, Department of Neurosciences, Faculty of Ophthalmology, University of the Witwatersrand, Johannesburg, South Africa; and, Department of Neurosciences, Faculty of Ophthalmology, Manchester Royal Eye Hospital, Manchester, United Kingdom
Natasha Naidu, Department of Neurosciences, Faculty of Ophthalmology, University of the Witwatersrand, Johannesburg, South Africa
Ismail Mayet, Department of Neurosciences, Faculty of Ophthalmology, University of the Witwatersrand, Johannesburg, South Africa

Abstract

Background: Intraocular pressure (IOP) measurement should be accurate in a paediatric population with primary congenital glaucoma (PCG).

Aim: This study aims to investigate the difference between the change in IOP measurements using rebound tonometry (RBT) and handheld applanation tonometry (AT) (Perkins applanation tonometer [PAT]) in patients with and without PCG.

Setting: Johannesburg, South Africa.

Methods: Measurements were taken under anaesthesia, using RBT and AT at 0 min, 5 min and 10 mins after induction and prior to intubation. Corneal pachymetry and corneal diameters were measured.

Results: Sixty-five children were included, 19 with PCG and 46 without PCG. The mean age (standard deviation [s.d.]) was 3.2 (2.25) years and 4.8 (2.4) years, respectively. The overall mean difference in IOP between RBT and PAT across both PCG and non-PCG groups was found to be 4.92 mmHg (95% confidence interval [CI]: 2.80 – 7.03) p < 0.001, with RBT having higher readings. This difference was greater in the PCG group, with the IOP difference of 9.05 mmHg (95% CI: 2.6 – 15.5) p = 0.004. Mean corneal pachymetry (s.d.) was 585.6 (81.48) µm in the PCG group and 518.31 (39.9) µm in the non-PCG group. Univariate analysis showed that IOP was significantly related to corneal pachymetry, with a 11 mmHg increase in IOP for every 100 μm change in corneal thickness for measurements done with RBT (p < 0.001), compared to 4 mmHg using PAT (p = 0.008).

Conclusion: Intraocular pressure measurements done with RBT in children with and without PCG were overestimated compared to PAT.

Contribution: This difference was more pronounced in PCG patients. In addition, IOP was significantly related to corneal thickness.


Keywords

intraocular pressure; applanation tonometry; rebound tonometry; primary congenital glaucoma; paediatric ophthalmology; tonometry; glaucoma; corneal pachymetry.

Sustainable Development Goal

Goal 3: Good health and well-being

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