Original Research

The effect of 1% tropicamide on central corneal thickness and intraocular pressure

Dimakatso G. Mashala, Bevily Nukeri, Alpheus S. Phaka, Angela N. Mashabu, Mlungisi J. Fakude, Phillip M. Seabi, Matome Mmakgaha, Ramadimetja P. Sedibeng
African Vision and Eye Health | Vol 83, No 1 | a862 | DOI: https://doi.org/10.4102/aveh.v83i1.862 | © 2024 Dimakatso G. Mashala, Bevily Nukeri, Alpheus S. Phaka, Angel N. Mashabu, Mlungisi J. Fakude, Phillip M. Seabi, Matome Mmakgaha, Ramadimetja P. Sedibeng | This work is licensed under CC Attribution 4.0
Submitted: 22 April 2023 | Published: 31 January 2024

About the author(s)

Dimakatso G. Mashala, Department of Optometry, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa
Bevily Nukeri, Department of Optometry, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa
Alpheus S. Phaka, Department of Optometry, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa
Angela N. Mashabu, Department of Optometry, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa
Mlungisi J. Fakude, Department of Optometry, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa
Phillip M. Seabi, Department of Optometry, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa
Matome Mmakgaha, Department of Optometry, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa
Ramadimetja P. Sedibeng, Department of Optometry, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa

Abstract

Background: Dilating the eye with tropicamide may alter the intraocular pressure (IOP) because of an obstruction of the iridocorneal angle, resulting in decreased aqueous outflow drainage. Also, the repeated application of eyedrops and instrumentation could lead to increased central corneal thickness (CCT), consequently affecting IOP.

Aim: This study aimed to determine the effect of 1% tropicamide on CCT and IOP post-mydriasis among the University of Limpopo optometry students.

Setting: The data were collected at the optometry clinic of the University of Limpopo.

Methods: A within-subject experimental study was conducted on 59 healthy subjects aged 18 years – 28 years. A computer assisted simple random probability sampling was used to identify a sample of participants from the study population (N = 200). Baseline and post-mydriasis IOP (20 min, 30 min, and 45 min intervals) were measured with a Goldmann applanation tonometer. Central corneal thickness and IOP were analysed using means, correlations and paired t-tests.

Results: The mean CCT pre-mydriasis was 504.68 μm, and post-dilation was 507.90 μm, 510.08 μm and 509.25 μm at 20 min, 30 min, and 45 min, P = 026, p = 0.033, P = 0.004, respectively. Moreover, the mean IOP pre-mydriasis was 15.97 mmHg, and post-dilation was 16.85 mmHg, 16.46 mmHg and 16.85 mmHg over 20 min, 30 min, and 45 min of followed-up time, p = 0.140, p = 0.432, and p = 0.183, respectively.

Conclusion: Measuring IOP post-dilation is still valid; however, CCT should be measured before the instillation of tropicamide.

Contribution: This study analysed the effect of 1% tropicamide on CCT and IOP post-mydriasis in a clinical South African context.


Keywords

tropicamide; intraocular pressure; pre and post-mydriasis; central corneal thickness; Goldmann tonometry

Sustainable Development Goal

Goal 15: Life on land

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