https://doi.org/10.1177/1010539520979928 Asia Pacific Journal of Public Health 2021, Vol. 33(1) 147–149 © 2020 APJPH Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1010539520979928 journals.sagepub.com/home/aph Short Communication Introduction The emergence of coronavirus disease caused by airborne severe acute respiratory syndrome coronavirus has high- lighted the critical role of respiratory personal protective equipment. Although health care workers (HCWs) from all specialties are at a high risk of exposure to the contagion, the risk for ophthalmologists and otolaryngologists is theoreti- cally more, owing to the proximity with the patients during clinical examinations, substantiated by the higher mortality rate among the HCWs associated with these specialties dur- ing the initial Wuhan outbreak. 1 Despite guidelines issued by various agencies for patient care using personal protective equipment, controversies per- sist regarding the different types of masks and respirators required to protect HCWs during clinics and surgeries. Risks of Transmission in Ophthalmic Settings: Can Face Covers Replace Masks? The slit-lamp examination is performed in proximity, at a dis- tance of <0.5 m (3 feet), thereby increasing the probability of exposure; additionally, frequent verbal communication required while examination can promote the direct transmission of infec- tive droplets, further escalating the risk. The direct contact with the conjunctival and tear secretions also adds to the risk. 1 Since most practices primarily consist of outpatient clin- ics with a high turnover, the waiting areas and examination room create a potential space for close proximity and proba- ble source of outbreaks. The transmission can be impeded by the use of breath shields and face covers but cannot be used as replacements for masks and respirators for effective pro- tection. 2 As the clinics reopen post lockdown measures enforced across the world, it is essential for the both the phy- sicians and patients to rely on the available masks in compli- ance with the guidelines, to minimize transmission and safely reverting back to consultations and procedures. Comparable Efficacy of Masks Masks are described as physical barriers that prevent exchange of airborne material between the wearer and the environment and should ideally cover the mouth and nose and should be tied tightly enough to prevent air egressing inside. The application of different types of masks are sum- marized in Table 1. Cloth Masks Versus Surgical Masks Cloth masks do not provide adequate protection especially in hospital settings and improper handling, poor filtration, moisture retention, and inadequate disinfection add to increased risk of infection. MacIntyre et al showed an increased rate of respiratory infections in the group using cloth mask versus those with surgical masks. 3 If these results by the authors could be extrapolated with a similar study done before, the protection offered by the surgical masks was 92% more in comparison with cloth masks for influenza-like illness. 4 Thus, cloth masks must be avoided by HCWs. Surgical Masks Versus Respirators Apart from the standardized testing required for certification, the factors that govern the protection offered by respirators includes particle size, filter penetration, and the face seal leak- age. These devices do not function at a constant flow rate, rather a more cyclical flow, which imitates the environmental conditions, thereby making the inspiration flow and the breath- ing flow rates other two important aspects to assess the effi- ciency. Addressing these considerations, He et al, while comparing the two, stated that particle size and breathing flow rate were more important than breathing frequency while deter- mining the filter penetration. The leakage was considered a function of particle size and the inspiratory flow rate, where leakage continued to increase till the particle size of 50 nm, while particle more than 50 nm did not have a significant effect. 5 979928APH XX X 10.1177/1010539520979928Asia Pacific Journal of Public HealthSingh et al research-article 2020 1 Department of Ophthalmology, Government Medical College and Hospital, Chandigarh, India 2 Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA Corresponding Author: Parul Ichhpujani, Department of Ophthalmology, Government Medical College and Hospital, Sector 32, Chandigarh 160030, India. Email: parul77@rediffmail.com First Line of Defense in COVID-19: Masks in Clinical Practice Tanu Singh, MS 1 , Parul Ichhpujani, MS 1 , and Rohan Bir Singh, MBBS 2