The measurement of intraocular pressure over positive soft contact lenses by rebound tonometry


Purpose - To investigate if the accuracy of intraocular pressure (IOP) measurements using rebound tonometry over disposable hydrogel (etafilcon A) contact lenses (CL) is affected by the positive power of the CLs. Methods - The experimental group comprised 26 subjects, (8 male, 18 female). IOP measurements were undertaken on the subjects’ right eyes in random order using a Rebound Tonometer (ICare). The CLs had powers of +2.00 D and +6.00 D. Measurements were taken over each contact lens and also before and after the CLs had been worn. Results - The IOP measure obtained with both CLs was significantly lower compared to the value without CLs (t test; p < 0.001) but no significant difference was found between the two powers of CLs. Conclusions - Rebound tonometry over positive hydrogel CLs leads to a certain degree of IOP underestimation. This result did not change for the two positive lenses used in the experiment, despite their large difference in power and therefore in lens thickness. Optometrists should bear this in mind when measuring IOP with the rebound tonometer over plus power contact lenses.

Publication DOI:
Divisions: College of Health & Life Sciences
Additional Information: © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. This is an open access article under the CC BY-NC-ND license (
Uncontrolled Keywords: contact lens,hydrogel,intraocular pressure,rebound tonometry,Optometry
Publication ISSN: 1989-1342
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://www.cli ... 3Fid%3D19572057 (Publisher URL)
PURE Output Type: Article
Published Date: 2016-07
Published Online Date: 2015-10-21
Accepted Date: 2015-08-03
Submitted Date: 2015-03-21
Authors: Zeri, Fabrizio (ORCID Profile 0000-0003-0529-555X)
de Cusatis, Mario
Lupelli, Luigi
Swann, Peter Graham

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