Face visors have become popular with hairdressers, hospitality and retail staff but are they a safe alternative to a face mask and what protection do they provide?
Studies are limited on their efficacy but one Northern Ireland doctor has said they should not be worn without an additional face covering.
Northern Ireland council chair of the British Medical Association (BMA) Dr Tom Black said wearing a visor alone does not protect the wearer or those around them.
"Face visors are not designed to protect the mouth and nose; they are designed to protect the wearer’s eyes from liquids, they are not designed to offer anyone else protection," he said.
"A visor is open at the bottom and around the sides and this allows for the free flow of droplets from the mouth and nose out the sides of the mask.
"We know that infected particles can be spread even with normal breathing, so the risk is always there for infected droplets to escape and possibly infect other people," he said.
Masks with exhalation valves should not be used as these could allow infected air to escape through the valve, he explained.
"A face covering is worn snugly over the nose and mouth and this means there is less chance of infected droplets escaping and infecting other people," he added.
"For the general public a cotton mask that can be washed is suitable, ideally it should be three layers of thick and tightly woven fabric.
"If someone does want to wear a visor, they need to also wear a face covering otherwise neither they nor people around them are protected."
The Centre of Disease Control in the United States also advised that visors are primarily used for eye protection for the person wearing them.
"At this time, it is not known what level of protection a face shield provides to people nearby from the spray of respiratory droplets from the wearer.
"There is currently not enough evidence to support the effectiveness of face shields for source control. Therefore, CDC does not currently recommend use of face shields as a substitute for masks," scientists said.
Wearing a mask may not be feasible in every situation for some people – for example, people who are deaf or hard of hearing, or those who care for or interact with a person who is hearing impaired.
It has some guidelines for people who may feel they have no option but to choose a visor.
Some visors provide better control than others. These include face shields that wrap around the sides of the wearer’s face and extend below the chin, and hooded face shields.
Shields should be disposed of after a single use and are not recommended for newborns or infants, they added.
In Northern Ireland, Executive advice does not recommend face shields as a sole method of protection.
Government advice states: "Face visors do not offer the same protection as a face covering which covers the nose and the mouth.
"The use of cloth face coverings are therefore recommended, as they provide much better protection from the risk of infection from the COVID-19 virus."