Safely measuring IOP during COVID-19 pandemic

A team of investigators from the Department of Ophthalmology, University of Washington, Seattle, led by Christine Petersen, MD, underscored the importance of accurate and precise measurement of intraocular pressure (IOP) during ophthalmic examinations.

However, the COVID-19 pandemic has made measuring IOP challenging because of the potential to spread the virus.

The SARS-CoV-2 virus can spread via droplets, microaerosols, or direct contact in the ophthalmology clinic. Tonometry poses a high risk of contamination. Single-use disposable equipment can address this issue.

The investigators reviewed the safety measures and compared various tonometry methods with the gold standard, Goldmann applanation tonometry (GAT).¹

The safety of the GAT procedure can be increased by adopting single-use applanation tips, they advised, but clinicians should be alert to the tip variability in the endpoint of tonometry. They also advised that discarding the tip when there is a problem is advisable following by repeating the measurement using a second tip.

Other methods of measuring IOP, the noncontact methods using an air puff device or an Ocular Response Analyzer (Reichert Technologies), also can be challenging because of the potential for droplets or aerosols to form. These methods likely should not be used if there is concern about infection with SARS-CoV-2.

The Tono-pen (Reichert) and iCare (iCare Finland Oy) devices are handheld portable instruments with single-use disposable tips or covers that come into contact with the eye, which is advantageous.

“Overall, studies have demonstrated good correlation between these devices and GAT,” Peterson and the team concluded. “Clinicians must balance the risk of microbial transmission with that of accurate and reproducible tonometry.”

Reference

Petersen CA, Chen A, Chen PP. How should we measure intraocular pressure in the era of coronavirus disease 2019? Balancing infectious risk, cleaning requirements, and accuracy. Curr Opin Ophthalmol 2022;33:67-72; doi: 10.1097/ICU.0000000000000831