Noninvasive Visualization of the Tear Film Microaerosol During Noncontact Tonometry Measurements.

Purpose

To investigate the aerosol generation by a noninvasive real-time observation device and assess the conditions relating to aerosolization during intraocular pressure (IOP) measurements using a commercial noncontact tonometer (NCT).

Study design

Prospective experimental and healthy eye studies.

Methods

In an initial experimental study, we devised a model mannequin eye to investigate how air puff pressure and IOP of the eye affected aerosol generation. In the human study including 20 healthy volunteer control subjects, the number of tear aerosol particles generated at 20 and 40 mm Hg air puff pressures with and without eye drop was investigated. The recorded aerosol visualization video was analyzed and the number of aerosol particles generated in 5 seconds after IOP measurement was measured.

Results

The experimental and human studies confirmed the aerosol generation during NCT measurements. In the experimental study, when the air puff pressures were set at 20 and 40 mm Hg, a lower IOP (5 mm Hg) generated significantly more aerosols than a higher IOP (25 mm Hg) (20 mm Hg, P = .0159; 40 mm Hg, P = .0079). There was also a significant positive correlation between the air puff pressure and the number of aerosol particles in both high- and low-IOP eyes (P < .001). At an air puff pressure of 40 mm Hg, the amount of aerosol generated was significantly higher with eye drop than without eye drop (P = .047).

Conclusions

NCT generates significant aerosolization from the tear film, the amount of which is determined by the IOP and the air puff pressure and the presence of eye drop use before the measurements.