Intraocular Pressure Measurement after Photorefractive Keratectomy : Does Contact Area Matter?
|Vetrugno Michele1*, Maino Anna2, Ferreri Paolo1, Cardia Giuseppina1, Trerotoli Paolo3, Serio Gabriella3 and Sborgia Carlo1|
|1Department of Ophthalmology, University of Bari, Italy|
|2Manchester Royal Eye Hospital, Manchester, UK|
|3Department of Biomedical Sciences and Human Oncology, University of Bari, Italy|
|Corresponding Author :||Michele Vetrugno
Diaprtimento di Oftalmologia, Universitaâ di Bari
Policlinico, piazza G Cesare 11, 70124 Bari, Italy
E-mail: [email protected]
|Accepted September 28, 2010; Published September 29, 2010|
|Citation: Michele V, Anna M, Paolo F, Giuseppina C, Paolo T, et al. (2010) Intraocular Pressure Measurement after Photorefractive Keratectomy : Does Contact Area Matter? J Clinic Experiment Ophthalmol 1:102. doi:10.4172/2155-9570.1000102|
|Copyright: © 2010 Michele V, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
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Background: Refractive laser surgery induces substantial changes in corneal structure, causing inaccurate intraocular pressure (IOP) readings. Pascal dynamic contour tonometry (PDCT) and Icare rebound tonometer (RBT) are two novel devices that do not depend on applanation to measure IOP. Purpose of this prospective study was to compare PDCT and rebound tonometry versus Goldmann tonometry (GAT) in a group of patients who underwent photorefractive keratectomy (PRK). Methods: Central corneal thickness and IOP were measured in 54 eyes before and after PRK. All IOP measurements were taken by the same examiner, using PDCT, RBT and GAT in a randomised, masked fashion. Results: After excimer laser surgery, PDCT measurements were higher than GAT (p<0.0001) and RBT (p=0.0012). Multiple linear regression analysis indicated that size of contact area was significant (b=-0.504; p<0.0001) while corneal thickness was not (b=0.003; p=0.169). Bland-Altman test showed that there was good agreement between RBT and PDCT (p=0.454), whereas GAT gave lower IOP values than both RBT (p=0.0103) and PDCT (p=0.0031). Conclusion: PDCT and RBT are less dependent on iatrogenic corneal changes than GAT and this might be related to their small contact area. In order to minimise IOP underestimation after excimer laser surgery, the clinician should consider adopting non-applanation tonometers like RBT and PDCT as an alternative to GAT.