Eye-protection and PPE compliance

According to a recent literature review by Kyriakaki et al. (2021), many eye injuries result from occupational activities and high-risk occupations include welding, farming, construction and manufacturing. However, PPE is also critical for workers in controlled environments. The demand for and use of PPE has increased dramatically in hospital settings since the start of the COVID-19 pandemic, as a way of preventing the transmission and spread of the virus. PPE is used in laboratories in various disciplines, where PPE protects the wearer and colleagues against mechanical insults, exposure to radiation and the harmful effects of chemicals.

An additional function can be found in clean rooms, where the prevention of contamination of the products being manufactured is crucial. The number of occupational chemical injuries might be rather low (Lurati, 2015), but they can be severe and require immediate intervention. Numerous accidents occur due to the lack or incorrect use of PPE. Eye injuries are no exception and it is estimated that 90% of eye accidents can be prevented by using the appropriate PPE (Kaiti et al., 2020). Strategies to optimise the use of PPE are needed to improve safety at work.

PPE impacts physical and mental well-being and performance

Notwithstanding the indisputable importance of eye protection, there are multiple reasons employees may disregard it. Recent studies of frontline healthcare providers during the COVID-19 crisis shed some light on PPE compliance. Frequently reported PPE related discomforts are headaches (79% of respondents), skin pressure injuries (66%), dizziness (49%), adverse vision (27%) and fatigue (16%) (Duan et al., 2020; Xiao-huan et al., 2020; Swaminathan et al., 2020). Besides, these studies report detrimental effects on well-being, such as a general increase in mental stress, anxiety (12%), insomnia (7%) and depression (6%).

It should therefore come as no surprise that these symptoms have a negative impact on clinical performance and productivity. According to those surveyed, this is due, among other things, to reduced dexterity and impaired vision. The study by Xiao-Huan et al. (2020) is of particular interest as it specifically examines the effects of safety goggles on the health and work status of nurses during COVID-19 management. Approximately 10% of the participants report that, as a result of wearing goggles, they encountered unsafe situations where viral infection or transmission was possible.

In addition, about 20% of the respondents report that they had made a medical error, defined as an unsuccessful clinical procedure such as unsuccessful venipuncture or medication errors, which can be associated with
goggle-related discomforts. Despite the indisputable benefits of goggles in terms of eye protection, these studies indicate that these work-related conditions can create unsafe situations for nurses and patients alike. It can be assumed that goggle-associated issues may also apply in other
controlled environments, including clean rooms. It is of primary importance to design protective eyewear that meets the needs of the users, so that all barriers that hamper the wider acceptance of these PPEs are removed.

Definition of Field of View (FOV)

It has previously been reported that fogging and scratching are two important obstacles to the use of protective eyewear (Lombardi et al., 2009). Here we would like to discuss another feature of goggles, namely the FOV. By definition, the visual field is the width of the area that a person’s eyes can see when they are focussed on a central point. For humans, this is typically around 200° to 220° in a horizontal plane as illustrated in figure 1. The term "field of view" is used in the sense of a restriction on what can be seen through external devices, such as when wearing spectacles or goggles. The most appropriate FOV depends on the task at hand. The FOV of binoculars varies depending on the magnification but is typically around 7°. For VR headsets, a typical FOV is around 50° (Lynn et al., 2020). The minimal FOV requirements for sports safety eyewear depend on the discipline. For squash and rugby, for example, a minimum value of 160° is reported, although a higher value of 180° is recommended (Dain, 2016; "Goggles Performance Specification ｜ World Rugby", 2021).

Fig. 1 Regions in the peripheral vision. Image modified from Wikimedia Commons, author Zyxwv99 (https://commons.wikimedia.org/wiki/File:Peripheral_vision.svg), https://creativecommons.org/licenses/bysa/4.0/legalcode.

Reduced FOV affects task performance

Peripheral vision impairment is believed to affect physical performance. It is reported that fast-pitch softball players have a larger size of visual field compared to a control group of nonathletes (Berg & Killian, 1995). In addition, a study by Kauffman et al. (2014) found that sports goggles adversely affect the perception of a visual stimulus in the peripheral visual field. The same study shows that goggles hamper the expected performance improvements upon repetition of the experiment. In everyday life, too, a restriction of the FOV has been shown to affect people’s behaviour and reduce performance.

Arthur (2000) investigated the effect of restricted FOV on two simple tasks, namely searching for a target and walking through a maze-like environment. A reduction in the FOV from 176° to 112° negatively affects task performance, measured as an increase in search time and walking time by 13.5% and 30.6% respectively. Toet et al. (2008) report similar results, but these authors use the unrestricted view, with a FOV of about 200°, as the reference. The time to complete a walking test with a reduced FOV of 120° increases by 23% compared to the unrestricted control. The number of footsteps also increases by 22%. These authors hypothesise that the restriction of the FOV leads to the deterioration in the maintenance of the postural equilibrium and a concomitant decrease in self-confidence.

It can be concluded from both studies that a restricted FOV has a negative impact on the ability to manoeuvre and on task performance. It is likely that such limitations also occur during occupational activities in controlled environments, including laboratories and cleanrooms. To ensure workplace safety and minimise the risk of errors during task performance, the provision of appropriate protective eyewear is therefore highly recommended.

Conclusion

Non-compliance with protective eyewear in controlled conditions, such as clean rooms and high-risk environments, needs to be discouraged and addressed. We argue that the field of view of safety goggles is a relevant factor, with a wider FOV contributing to user comfort, safety and quality of task performance. This feature should be included in the decision-making process when selecting and purchasing personal protective equipment.