Reliability of intraocular pressure measurements in a low contact drivethrough setting

ABSTRACT

Purpose: The COVID-19 pandemic has spurred innovation beyond traditional healthcare. At our institution, a drive-through intraocular pressure (IOP) measurement protocol using the iCare tonometer was established to facilitate low-contact monitoring of select glaucoma patients. However, the iCare may be prone to error due to variable measurement technique and local air currents.2We endeavored to assess the reliability of drive-through IOP measurements by comparing them with recent measurements taken in clinic settings. Methods: Inclusion criteria were all patients with drive-through IOP measurements performed from May 11-Aug. 11, 2020;exclusion criteria were any patients with IOP medication change or ophthalmic procedure between the studied IOP measurements. Drive-through IOP measurements were compared with the most recent prior in-clinic IOP measurements. Data was gathered using the Sight Outcomes Research Collaborative (SOURCE) data repository2. Results: The study group consisted of 338 patients receiving drive-through IOP measurements. Significant differences were found between drive-through IOPs and prior in-clinic measurements. The mean drive-through vs. in-clinic IOP OD was 17.0 mmHg (SD 5.3) vs. 14.5 mmHg (SD 4.2), and OS was 17.8 mmHg (SD 5.6) vs. 15.1 mmHg (SD 4.5), a difference of 17.6% OD and 17.8% OS. Differences between individual measurements ranged from-5.5 mmHg to +12 mmHg. 71.4% of drive-through IOPs were higher than corresponding in-clinic IOPs;22.7% were lower. 30.5% of drive-through IOPs were higher than >5 mmHg. In 18.4% of cases, drive-through IOP measurements resulted in management changes (typically, the addition of an IOP-lowering drop). In comparison, only 10.5% of in-clinic measurements resulted in management changes-the equivalent of a 75% increase in intervention. Conclusions: Low-contact forms of IOP monitoring will continue to play a role in teleophthalmology. However, our data reveals potential inaccuracies in drive-through iCare IOP measurements which tend to overestimate IOP, thus triggering interventions in more drive-through cases than typically seen in clinic.