Airborne pathogen projection during ophthalmic examination

Abstract

Purpose Microscale droplets act as coronaviruses (CoV) carriers in the air when released from an infected person and may infect others during close contact such as ophthalmic examination. The main objective of the present work is to demonstrate how CoV deposited droplets are projected during biomicroscopy and to discuss what kind of precautions should be taken in ophthalmic practice. Methods A coupled fluid-structure system comprising smoothed particle hydrodynamics and the finite element method has been built to assess the projection of droplets spreading from an infected person. Different conditions based on the maximum exit flow velocity from the infector's mouth during the ophthalmic examination were modeled. Results During exhalation, for which the exit flow is~1000 mm/s, the average horizontal distance of the flow front was2 00 mm while individual particles can reach up to~500 mm. In case of coughing or sneezing (corresponding to an exit flow of1 2,000 mm/s), the average horizontal distance of the flow front was~1300 mm. Conclusion During the ophthalmic examination, the proximity to the patient's nose and mouth was observed to be less than the horizontal distance of flow front particles. Even though mounted breath shields are used, particles flew beyond the shield and contaminate the ophthalmologist. Compared with the current protective breath shields, the use of a larger shield with a minimum radius of 18 cm is needed to decrease viral transmission.

Evidence of SARS-CoV-2 Transmission Through the Ocular Route

“…Aerosols can suspend in the air, flow beyond the shield, and then arrive at the ophthalmologists’ neck and clothing. 61 , 62 SARS-CoV-2 can remain viable in aerosols for at least 3 hours. 63 Once aerosols form, SARS-CoV-2 can bind to the ACE2 on the exposed ocular mucosa to cause infection.…”

Microstructural evaluation and recommendations for face masks in community use to reduce the transmission of respiratory infectious diseases

“…As illustrated in Fig. 1 , respiratory particles, which can remain in the air for some time as a result of coughing, sneezing, speaking or exhaled breath, can carry airborne pathogens and compounds and are one of the transmission routes for the infectious diseases [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] . Comprehensive reviews on face masks have been recently published to inform public, academia, and industry [27] , [28] .…”

No secret hiding place? Absence of SARS-CoV-2 on the ocular surface of 1145 hospitalized patients in a pandemic area

“…SARS-CoV-2 spreads via human-to-human and seems to be transmitted mainly through respiratory droplets and contact with infected persons, less commonly via smear infection [1,2,4,5]. Furthermore, there seems to be a significant risk for ophthalmologists and medical staff to be infected with SARS-CoV-2 during the ophthalmological examination, treatment, or care due to the close proximity to infected (but often still asymptomatic) patients or colleagues [1,2,4,[7][8][9]. In addition, this potentially high risk seems to affect the mental health of ophthalmologists and the medical staff resulting in anxiety and depression symptoms [10].…”