The Prevalence of fogging with protective eye wear and comparison of various techniques to reduce fogging in intensive care unit during COVID 19 pandemic-Fog Lens study

Personal protective equipment (PPE) is commonly used in healthcare to prevent healthcare worker (HCW) acquiring infections especially those spread by physical contact and airborne route(1). The use of PPE is recommended while dealing with patients who have potential to transmit infections. World health organisation (WHO)(2) has laid down recommendations for using PPE in the setting of highly infectious diseases like Ebola  and the recent SARS CoV 2 virus. PPE should consist of a gown, gloves, masks, respirators, eye protection as goggles, face shield, head covers and shoe covers(3) (7). The compliance of using PPE by HCWs is low and is influenced by many factors(5) (6).  Contamination of eyes and protective eye wear (PEW) were found especially when dealing with high risk procedures like surgeries(7)(8). One of the drawbacks of wearing protective eye wear is that the lenses tend to fog under certain conditions(9). Fogging of safety glasses is a nuisance and can hamper or delay work especially during life saving procedures and patient care.

There are few techniques described which can reduce fogging like modification in wearing a surgical mask, using anti-fog spray or lenses(10) (11). The common reason for fogging is change in temperature and humidity which causes moisture to condense on the surface of the eye wear, which is relatively cooler(12). This commonly occurs when moving from cold to warmer environment, increased physical activity which increases body temperature, rapid change of humidity, etc. The air trapped between the lens and the persons face is hot and humid, thus increasing the chance of fogging

Many studies regarding fogging of lenses while at work were done in experimental and non healthcare industry settings(13).  Few clinical studies have tried anti-fog sprays and its alternatives like baby shampoo, hibiscrub, chlorhexidine solution etc  to prevent fogging of endoscopy and laparoscopy lenses(14)(15)(16)(17). But no studies have been done on PEW fogging and techniques to reduce protective eye wear fogging in acute healthcare settings. So, we don’t know the prevalence of PEW fogging. Also, there is no single method available which can reduce fogging significantly which is effective, less costly and is doable at healthcare settings especially in intensive care unit.

We, with our current experience of using PPE during this COVID-19 pandemic, have found fogging of PEW as a major factor that affected the work efficiency and performing of skilled procedures. So, we devised a study to look for the prevalence of PEW fogging and to look at suitable combination of PPE with PEW that can reduce the fogging. Also, to evaluate the factors that affect fogging eye wears, the techniques adapted by HCW and challenges faced while using PEWs.

References:

1.        Recommendations - Personal Protective Equipment for Use in a Filovirus Disease Outbreak: Rapid Advice Guideline - NCBI Bookshelf [Internet]. [cited 2020 Jun 2]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK401160/

2.        World Health Organization(WHO). Infection prevention and control of epidemic- and pandemic-prone acute respiratory infections in health care. WHO Guidel [Internet]. 2014 [cited 2020 Jun 2];1–156. Available from: www.who.int/about/licensing/copyright\_form/en/index.html

3.        World Health Organization (WHO). Rational use of personal protective equipment for coronavirus disease 2019 ( COVID-19 ). Who. 2020;2019(February):1–7.

4.        Using Personal Protective Equipment (PPE) | CDC [Internet]. [cited 2020 Jun 2]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/hcp/using-ppe.html

5.        Loibner M, Hagauer S, Schwantzer G, Berghold A, Zatloukal K. Limiting factors for wearing personal protective equipment (PPE) in a health care environment evaluated in a randomised study. PLoS One. 2019 Jan 1;14(1).

6.        Honda H, Iwata K. Personal protective equipment and improving compliance among healthcare workers in high-risk settings. Vol. 29, Current Opinion in Infectious Diseases. Lippincott Williams and Wilkins; 2016. p. 400–6.

7.        Tukur J, Yakubu AA, Sheshe AA, Abubakar IS. Use of protective eyewear among surgeons in a tertiary hospital in northern Nigeria. Trop Doct [Internet]. 2007;37(1):40–2. Available from: http://www.who.int/hiv/topics/

8.        Lange VR. Eyewear contamination levels in the operating room: Infection risk. Am J Infect Control. 2014;42(4):446–7.

9.        Dain, S.J., Hoskin, A.K., Winder, C., Dingsdag, D.P. Assessment of fogging resistance of anti-fog personal eye protection. Ophthalmic Physiol Opt. 1999;19(4):357–361.

10.      Reed MJ. Preventing fogging of spectacles whilst wearing a protective face-mask. J R Coll Surg Edinburgh. 2001;46(6):377.

11.      SS, Malik MS. A simple method to prevent spectacle lenses misting up on wearing a face mask. Ann R Coll Surg England. 2011;93(2):168.

12.      Schurr MO, Kunert W, Arezzo A BG. The role and future of endoscopic imaging systems. Endoscopy. 1999;31(7):557–62.

13.      Crebolder JM, Sloan RB. Determining the effects of eyewear fogging on visual task performance. Appl Ergon. 2004;35(4):371–81.

14.      Seksun Chainansamit PPIAPKST. Baby Shampoo Versus Commercial Anti-fogging Solution to Prevent Fogging During Nasal Endoscopy: A Randomized Double-Blinded, Matched-Pair, Equivalent Trial - PubMed. J Med Assoc Thai  [Internet]. 2015 Aug [cited 2020 Jun 2];98(7):s128-131. Available from: https://pubmed.ncbi.nlm.nih.gov/26742380/

15.      Piromchai P, Kasemsiri P, Thanaviratananich S. Alternative agents to prevent fogging in head and neck endoscopy. Clin Med insights Ear, nose throat [Internet]. 2011 [cited 2020 Jun 2];4:1–4. Available from: http://www.ncbi.nlm.nih.gov/pubmed/24179399

16.      Manning TG, Perera M, Christidis D, Kinnear N, Mcgrath S, O’beirne R, et al. Visual occlusion during minimally invasive surgery: A contemporary review of methods to reduce laparoscopic and robotic lens fogging and other sources of optical loss. Vol. 31, Journal of Endourology. Mary Ann Liebert Inc.; 2017. p. 327–33.

17.      Song T, Lee DH. A randomized Comparison of laparoscopic LEns defogging using Anti-fog solution, waRm saline, and chlorhexidine solution (CLEAR). Surg Endosc. 2020 Feb 1;34(2):940–5.

Methodology:

The information regarding the study will be provided to all HCW beforehand explaining the study process and a written informed consent will be taken from the participants.

The PPE is donned in a dedicated room/area outside the COVID ICU.  A HCW is posted in the donning room who will serve as a link between COVID ICU and non-COVID ICU. The HCW will help their colleagues in donning PPE making sure they are covered fully. After donning PPE and before going inside the ICU, the study will be done. An observer will be sitting in the donning room wearing a N95 respirator and hospital scrubs. The seal check of N95 mask will be ensured as part of standard practice. The observer will first test for visual acuity of subject (both near and distant vision) without PEW and prescription spectacles. Once the PEW is donned, they will observe for presence/absence of fogging and severity of fogging with each of the techniques as mentioned below (figure1). The study will be done in 3 stages; first stage will be in donning room, then inside COVID ICU and finally after doffing. In the first stage, after donning the PPE the HCW will be asked to read the near (Jaeger) and distant vision (Snellen’s) charts for baseline value. Snellen’s charts will be placed at 6metres from the subject in a well illuminated area of the donning room. The baseline value of their visual acuity in each eye will be noted down. After donning the protective eyewear, each member will try out each of the following techniques (a combination of N95 and PEW)

• 1.      PPE with N95 respirator alone with protective eye wear (3M goggles)
• 2.      PPE with N95 mask and the goggles worn over PPE hood( to increase the distance from the subjects eyes)
• 3.      Wearing PPE with N95 mask and air dried goggles treated with soap and water
• 4.      Wearing PPE with N95 respirator with a tape to seal the upper edge in a bid to avoid air leak
• 5.      Wearing PPE with 3M half face elastomeric respirator with protective glass (when available – this step is not mandatory for all)

They will be observed for a period of 2 minutes for each technique. Presence/absence of fogging, time taken for fogging to occur and disappear and severity of fogging will be documented at the end of 2 minutes. For severity of fogging the independent observer will document the quadrants of the lens which have been fogged. The lens will be divided into four quadrants(R1,R2,R3,R4; L1,L2,L3,L4) by two perpendicular imaginary lines crossing at the centre of each lens and the quadrants involved will be shaded in the CRF. (See Fig1). In addition to this all HCWs will be assessed for degree of vision impairment by using near and far vision charts for visual acuity for each technique.

Figure 1: labelled quadrant of spectacle lens (R –Right, L – Left)

The HCW will also be objectively assessed for the clarity of vision.  Test for vision clarity (without change of posture)

1. Distant vision – Snellen’s chart placed at 6 meter distance
2. Jaeger’s chart- near vision

The HCW will be asked to read the sentences in Jaeger’s charts for near vision and Snellen’s chart for distant vision assessment. It will take approximately 2 mins for each category/technique and the first stage will take around 10 minutes to complete per HCW.

After the first stage of study the HCW will be entering the COVID ICU wearing full PPE as per standards/ department policy. They will be allowed to use any of the above techniques or a combination of techniques. The investigators will note down which technique they used.

The HCW will be observed for fogging after approximately after 30 minutes to one hour. They will be observed by an independent observer when available inside COVID ICU or a video call will be made to them to assess fogging from outside the ICU. The independent observer will observe for presence and severity of fogging by noting the number of quadrant affected. Near vision using the Jaegers charts will also be assessed and noted down.

The ICU temperature and humidity will be recorded during the study day and during study period (2nd stage of study, i.e. 30mins to 1 hour after entering COVID ICU). The temperature of the lens/goggles will be measured using handheld non contact device. The temperature and humidity of the environment will be measured by digital thermo- hygrometer. The health care worker will be asked for methods used by them to reduce fogging while working or during procedure.  After doffing the PPE the HCW will be given a set of simple questions to answer regarding the challenges faced while using PEW.

Definitions:

Fogging: Any misting of PEW lens is defined as PEW fogging

Fogging hampering vision:  Fogging hampering vision is defined when

1.      Presence of fogging AND Decrease in visual acuity in either eye as compared to baseline while reading  near and distant vision charts OR

3.      Change in head posture while trying to read Snellen’s and Jaegers charts

Soap coated PEW: Soap coated PEW are the goggles cleaned with Microshield 4% chlorehexidine gluconate solution and air dried for 1 hour.

Tape: preferably an adhesive micropore or any adhesive plasters (e.g. transpore)