Intraocular Pressure Through Varying Contact Lenses.

Purpose: To evaluate the effect of newer contact lenses on lOP readings taken by NCT with the lenses in place on the eye.
Methods: Non-contact tonometry readings were taken of both eyes before a lens was inserted, then again after a contact was inserted into the right eye only. Random lenses were chosen to undergo a third pressure reading after the lens was removed. The lenses tested included the Acuvue, Acuvue Bifocal, Acuvue Advance, Focus Night and Day, Focus Progressive, 02 Optix and Frequency 55 Multifocal. All lenses were -3.00D in power, and+ 1.50 or low add when appropriate.
Results: This study showed minimal difference between control pressure readings and readings overtop of contact lenses in each of the lenses tried except for the higher dK Acuvue
Advance, Focus Night and Day and 02 Optix. In each of these lenses there was a
difference of 2mmHg or more. Conclusions: Common materials such as the etafilcon A, lotrafilcon A and methafilcon A have
minimal effect on lOP using NCT. Higher dK, and lower water content lenses such as
galyfilcon A, lotrafilcon B and lotrafilcon A all show lower lOP readings by 2mmHg or more as compared to pre-contact lens measurements.