Qi, N., Lockington, D., Wang, H., Hill, N. A. , Ramaesh, K. and Luo, X. (2018) Modelling floppy iris syndrome and the impact of phenylephrine on iris buckling. International Journal of Applied Mechanics, 10(5), 1850048. (doi: 10.1142/S1758825118500485)
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Abstract
Abnormal iris movement (floppy iris syndrome) during intraocular surgery is associated with an increased risk of intraoperative complications. We have previously investigated this scenario with respect to intracameral air in corneal endothelial transplantation, and described the concept of iris buckling. As a number of clinical interventions are recommended for addressing floppy iris syndrome, we wished to evaluate the impact of intracameral phenylephrine on iris buckling and so refine our mathematical model. We considered the stability of an iris structure under a uniform pressure loading. We performed mathematical and computational simulations to demonstrate iris buckling, and then altered the parameters to assess the impact of phenylephrine on the model. We elucidated a number of buckled iris configurations which become unstable as the intraocular pressure increased, for transversely isotropic iris material properties, and identified a positive correlation between the critical pressure and the iris stiffness. A mechanical analysis with a dilated pupil (mimicking phenylephrine use) was also conducted, and demonstrated a significant increase in the critical pressure required to induce iris buckling. We have shown that iris buckling can arise at lower pressures when the iris stiffness is reduced, as in floppy iris syndrome. The use of phenylephrine was shown to prevent iris movement (buckling) by increasing the required critical pressures. This refined model demonstrates the positive effectiveness of phenylephrine in the management of floppy iris syndrome and gives evidence to the clinical practice of using this as a preventative measure.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Luo, Professor Xiaoyu and Hill, Professor Nicholas and Qi, Dr Nan and Wang, Mr HuiMing and Ramaesh, Dr Kanna |
Authors: | Qi, N., Lockington, D., Wang, H., Hill, N. A., Ramaesh, K., and Luo, X. |
College/School: | College of Medical Veterinary and Life Sciences College of Science and Engineering > School of Mathematics and Statistics > Mathematics |
Journal Name: | International Journal of Applied Mechanics |
Publisher: | World Scientific Publishing |
ISSN: | 1758-8251 |
ISSN (Online): | 1758-826X |
Published Online: | 11 July 2018 |
Copyright Holders: | Copyright © 2018 The Authors |
First Published: | First published in International Journal of Applied Mechanics 10(5):1850048 |
Publisher Policy: | Reproduced under a Creative Commons License |
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