Table 2.
Design considerations for a filtered eye mask (FEM).
| Design options | Considerations for optimization |
|---|---|
| Mask material | Capable of being washed to eliminate build up of potentially dangerous particles on the outside of the mask (e.g. with soap and water). |
| Filter types | Optimal protection against virus particles contacting the eyes is via a high-efficiency air filter (e.g. N95 and N100). A higher protection efficiency filter (e.g. N100) may be used for higher-risk activities (e.g. prolonged direct contact with an active COVID-19 patient). |
| Technique of filter replacement | A removable and replaceable filter would be cost-effective (e.g. filters could come in small packages, opened and be secured in place via clamps, buckles or straps). |
| Frequency of filter replacement | Optimal protection will be achieved when a new filter is placed on the eye protection each time it is used, although reuse of filters can be performed under specialized protocols if supplies are short (e.g. quarantine used filters for a specified period of time). |
| Securing filter to the mask | Reliable seal during use is essential to keep the air mass in front of eyes virus-free (e.g. cartridge fixation may prove more effective than tape, which has the potential to fall off and ruin the seal). |
| Size of filter | Optimum size may depend on multiple factors, including moisture content of user (e.g. amounts of natural tears, perspiration, etc.) and environment (e.g. temperature). |
| Positioning of filter on mask | Optimal positioning would be in a location (e.g. side of mask) capable of adequate ventilation (e.g. not covered by head cover) and providing an adequate field of view (e.g. not blocking user's view). |
| Mask seal to face | A comfortable seal is important for good user compliance (e.g. an air-filled, silicone balloon for contact with the face). |
| Variations in securing mask to head | An air-tight seal with the face is needed to prevent air from leaking in along the skin surface of the face (e.g. a strap coursing over the back lower and back upper portions of the user's head). |