Another contact lens that can measure IOP and ocular pulse amplitude (OPA) over a continuous 24-hour period is on the horizon, and results of an early study are favorable.

The proof of concept, single-center investigation, published in the British Journal of Ophthalmology, included both glaucoma and healthy individuals. The research team from Switzerland, the US and Poland took IOP and OPA readings from the pressure-measuring contact lens in one patient’s eye at the point of application and compared them to results from Goldmann applanation tonometry and dynamic contour tonometry in the same eye just prior to lens placement. The investigators also measured IOP and OPA with the pressure-measuring contact lens on the study eye during a water-drinking test and compared the results with dynamic contour tonometry readings in the fellow eye.

The study also observed 24-hour IOP and OPA curves in eight subjects. The approximate IOP difference between the pressure-reading contact lens and tonometry on the same eye was within ±5mm Hg in 75% (Goldmann) and 87.5% (dynamic contour tonometry) of subjects. Both the contact lens and dynamic contour tonometry detected IOP variations due to the water-drinking test for an average increase of 2.43mm Hg and 1.85mm Hg, respectively. The researchers also noted IOP differences between the contact lens and dynamic contour tonometry in fellow eyes within ±5mm Hg for 97.2% of time points. The difference between OPA in the fellow eyes was within ±5mm Hg for 85.5% of the time points.

This marks the first-in-human study for 24-hour continuous measurements of IOP and OPA with the pressure-reading contact lens, the study reported.

“This device is noninvasive and has good comparability with standard tonometry,” the researchers wrote in their paper.

Wasilweicz R, Varidel T, Simon-Zoula S, et al. First-in-human continuous 24-hour measurement of intraocular pressure and ocular pulsation using a novel contact lens sensor. Br J Ophthalmol. February 19, 2020. [Epub ahead of print].