Bactericidal Efficacy of Ultraviolet-C Light on Virtual Reality Devices: In Vitro Assessment of Bacterial Killing.

Background: Virtual reality (VR) headsets are increasingly used in health care settings for a variety of clinical indications, yet processes to ensure safe use between patients are not well-established. Centers vary in how these processes are performed. Most use disinfection wipes that require manual contact with VR devices for a specified dwell time to allow for sufficient pathogen killing, which may introduce manual error and device degradation over time. Ultraviolet-C light (UV-C) devices offer a no-touch, low-cost, and passive method to achieve pathogen killing without the harms of chemical contact-based disinfectants. The use of UV-C for disinfection has been studied for some medical devices but its efficacy for microbe killing on VR headsets is not well-established.

Objective: This study aims to determine the bactericidal efficacy of UV-C on VR headsets through quantifying UV-C irradiance and bacterial killing of 3 commercially available UV-C devices.

Methods: Three commercially available, low-cost UV-C devices were tested for UV-C energy output at multiple positions, angles, and times across the devices' zone of disinfection. The top and lens of a VR headset, the Meta Oculus Quest 2, were artificially inoculated with high quantities of 3 different strains of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, and Staphylococcus epidermidis) and subjected to UV-C light according to each device's manufacturer's instructions for use. The primary outcome was the amount of bacterial killing after exposure to UV-C light.

Results: All 3 UV-C devices produced a UV-C dose that ranged from 3.57 to 195.37 mJ/cm2, depending on proximity, angle, irradiance, and time the sensor received. At least 3-log10 killing of all 3 strains of bacteria was achieved for each of the tested UV-C devices; however, there was variability by organism with respect to UV-C device and VR headset location within the device, notably with the proximity of the bacteria to the bulb. S aureus and P aeruginosa were more readily killed than S epidermidis, with increased bacterial killing occurring with increased UV-C exposure doses. There was no experiment in which all bacteria were killed.

Conclusions: UV-C dosage increased with exposure irradiance, time, proximity, and angle to the bulb for all 3 UV-C devices. Bacterial killing on the top and lens of a VR headset occurred in all 3 UV-C devices when run according to their manufacturer's instructions for use, although full bacterial killing did not occur in any experiment. UV-C may be an effective method for microbial killing on VR equipment with low-level contamination.