EDITORIAL

Corona Virus Nanoparticles and Enhanced

Respiratory Protection for Outpatient

Ophthalmic Practice

Nick Kopsachilis¹, Rashid Zia²

¹Lead Consultant Ophthalmologist; East Kent Hospitals University Foundation Trust, United Kingdom

²Lead New Hayesbank Ophthalmology Services, Ashford Kent United Kingdom

The Covid-19 pandemic has emerged rapidly and

is now part of our everyday life and work. At the time

of writing this script, all routine clinical activity and

surgery that had previously been stopped is set for a

phased reopening over the next 6 weeks to 6 months.

Extensive planning has been undertaken to cater to the

significant backlog but the Sword of Damocles hangs

over all of us as an imminent risk of a second peak and

another lockdown looms.

no longer categorised as a high consequence infectious

disease and therefore enhanced PPE is not

recommended”¹and that ophthalmologists should

wear standard PPE including a surgical fluid resistant

mask, plastic apron, gloves and eye protection when

examining COVID positive patients¹. As reassuring as

this may sound, this recommendation is not

scientifically backed by the literature citing systematic

review on respiratory protection against airborne

nanoparticles discussing nano particles’ behaviour and

penetration of facial seals of masks.²Corona particle is

classified as a nanoparticle – an average diameter of

the virus particles is around 125 nm (0.125 μm ).^3,4

Standard infection control precautions (SICPs) and

transmission-based precautions (TBPs) must be used

when managing patients with suspected or confirmed

Covid-19. Public Health England has advised, “SICPs

should be used by all staff, in all care settings, at all

times, for all patients”¹. At this stage, we believe it is

extremely important to understand that the current

discussion on using enhanced personal protective

equipment (PPE) is to prevent specifically from

Corona infection and transmission. Ophthalmologists,

ophthalmic nurses and optometrists are at the frontline

of this crisis and their work related risks are often

undervalued. In its most recent guidelines, Public

Health England (PHE) has advised that “COVID19 is

It may seem counter-intuitive that a 0.3 microns

particle that is 30 times larger would be harder to

capture than 0.1 micron size Corona particle but the

root of the problem is in our thinking that respiratory

masks act like nets - if a particle is smaller than the

holes in the net, it gets through and the smaller the

particle, the harder it is to capture. This logic works

for particles bigger than 0.3 microns. Such particles

(i.e. > 0.3 microns) either cannot fit through or their

inertia causes them to hit the filter fibres– a process

called impaction and interception. Nanoparticles under

the 0.3 microns have very little mass and they are

bounced around like a pinball when they hit gas

molecules. This is known as Brownian motion. These

tiny particles are small enough to fit through 0.3

micron filters if they flow straight. As they fly in

zigzag patterns, they end-up hitting the fibres and

getting stuck. The smaller the particles, the fewer will

slip through.⁵Electrostatic attraction is another

efficient method of capturing particles of various sizes

from the airstream. This method incorporates

electrically charged fibres or granules, which are

How to Cite this Article: Kopsachilis N, Zia R.

Corona Virus Nanoparticles and Requirement of

Enhanced Respiratory Protection for Outpatient

Ophthalmic Practice. Pak J Ophthalmol. 2020; 36 (3):

191-193.

Doi: 10.36351/pjo.v36i3.1079

Correspondence to: Rashid Zia

New Hayesbank Ophthalmology Services, United Kingdom

Email: rashidzia@nhs.net

Pakistan Journal of Ophthalmology, 2020, Vol. 36 (3): 191-193

191

Nick Kopsachilis, et al

embedded in the filter to attract oppositely charged

particles from the airstream. The attraction between

the oppositely charged fibres and particles is strong

enough to effectively remove the nanoparticles from

the air.⁶Hence, even masks with electret filters that

may not be effective against 0.3 microns may be more

effective in stopping nanoparticles.⁶All N95, FFP2,

FFP3 and many surgical masks have electret filters of

varying efficiencies.

To summarise, despite being significantly smaller

than 0.3 microns (filtration limit of most masks

including N95, FFP2 and FFP3), Corona virus

particles (0.1 micron ) can still be effectively filtered

by all kind of masks with electret filters. However,

none of the masks offer effective protection especially

against aerosols unless fit tested. The evidence is

overwhelming that ophthalmologists require enhanced

PPEs including surgical cap, gown, fit tested mask,

gloves and goggles for all ophthalmic examinations.

Hesitation in implementing new PPE guidance for

ophthalmology will probably cost lives.

Thus, PHE guidelines of using simple masks may

be protective against droplet and even against

nanoparticles if they contain an electret filter.

However, it completely ignores the increased risk of

deadlier aerosol related infection via lack of facial

seals in ordinary surgical masks.⁷PHE recommends

wearing a respirator mask and enhanced PPE when

performing an aerosol generating procedure¹yet it fails

to recognize aerosol generation and prolonged

exposure to the virus by ophthalmologists during

Conflict of Interest

Author declared no conflict of interest

Authors’ Designation and Contribution

Nick Kopsachilis; Consultant Ophthalmologist:

Manuscript writing, Literature review, Final review.

common

daily

outpatient

procedures

and

examinations.

Rashid Zia; Consultant Ophthalmologist: Manuscript

writing, Literature review, Final review.

Ophthalmic examination includes close working

distance to our patients at the slit lamp (< 20 cm).

Many nasolacrimal outpatient procedures can easily

convert into droplet infection and even aerosol i.e.

refluxes from lacrimal washout. Handling of cleaning

tissues contaminated with tears and excessive eye

drops is a particularly high risk for droplet infection. It

is known that the viral load accumulation can increase

the severity of the disease.⁸In addition, many slit lamp

based procedures and examinations can lead to

prolonged exposure and in some cases even aerosol

generation. Thus, loosely fitted surgical masks, despite

their electret filter to trap nanoparticles may offer little

or no protection at all.

REFERENCES

1. COVID-19: infection prevention and control guidance

(2020). Available from:

https://assets.publishing.service.gov.uk/government/upl

oads/system/uploads/attachment_data/file/886668/COV

ID19_Infection_prevention_and_control_guidance_co

mplete.pdf

2. Ntlailane MGL, Wichmann J. Effectiveness of N95

respirators for nanoparticle exposure control (2000–

2016): a systematic review and meta-analysis. J

Nanopart Res. 2019; 21 (8): 170.

3. Goldsmith CS, Tatti KM, Ksiazek TG, Rollin PE,

Comer JA, Lee WW, et al. Ultrastructural

characterization of SARS coronavirus. Emerg Infect

Dis. 2004; 10 (2): 320-26.

4. Fehr AR, Perlman S. Coronaviruses: an overview of

their replication and pathogenesis. Methods Mol Biol.

2015; 1282: 1-23. Doi: 10.1007/978-1-4939-2438-7_1.

5. Shaffer RE, Rengasamy S. Respiratory protection

against airborne nanoparticles: A review. J Nanopart

Res. 2009; 11 (7): 1661-1672.

6. Sun Q, Leung WW. Enhanced nano-aerosol loading

performance of multilayer PVDF nanofiber electrets

filters. Sep Purif Technol. 2020; 240: 116606.

7. Doremalen VN, Bushmaker T, Morris DH,

Holbrook MG, Gamble A, Williamson BN, et al.

Aerosol and Surface Stability of SARS-CoV-2 as

Compared with SARS-CoV-1.N Engl J Med. 2020; 382

Aerosol can be produced by talking alone and its

contact with an exposed conjunctiva is known to cause

infection.⁹Furthermore, conjunctivitis can be the first

manifestation of COVID-19 without fever or coughing

and ophthalmologists working in eye casualty can be

caught off guard and be at increased risk of infection.

It is probably not a coincidence that 3 out of 8

surgeons who died in Wuhan were ophthalmologists.

Therefore, Ophthalmology should be considered as a

high risk category between healthcare workers because

of prolonged exposure to the patients, droplets and

aerosol generating outpatient procedures during the

ophthalmic examination.

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Pakistan Journal of Ophthalmology, 2020, Vol. 36 (3): 191-193