Effect of lotrafilcon A silicone hydrogel contact lens on intraocular pressure measurement

The present paper aims to assess the effect of lotrafilcon A contact lenses (CL) in situ on intraocular pressure (IOP) measurement performed with three portable tonometers (ICare, Tonopen and Perkins). This cross-sectional study included thirty young healthy subjects. Intraocular pressure measurements without CL were performed first, followed by IOP measurements with CL for twenty minutes. ICare IOP measurements obtained with lotrafilcon A CL overestimated IOP values without CL by 1 mmHg (P<0.001). However, both techniques displayed close level of agreement (95% LoA, -4.17 to +1.63 mmHg). Also, differences between both methods tended not to increase (P=0.9). No significant differences were observed between IOP measurements without and with CL for Perkins (paired-t test, P=0.23) and Tonopen XL (pairedt test, P=0.17). In conclusion, adequate IOP measurements through zero power lotrafilcon A silicone hydrogel CL can be obtained with all three tonometers in healthy eyes, although, in case of ICare, the practitioner must be aware of the 1 mmHg overestimation with CL.