TNOA Journal of Ophthalmic Science and Research

: 2020  |  Volume : 58  |  Issue : 2  |  Page : 81--88

COVID -19 and ophthalmic practice

T Nirmal Fredrick1, Murali Ariga2, Sharmila Devi Vadivelu3, Ramesh Dorairajan4, Amogh Laxman Jambagi3,  
1 Department of Ophthalmology, Nirmal's Eye Hospital, Chennai, Tamil Nadu, India
2 Department of Ophthalmology, Sundaram Medical Foundation, Chennai, Tamil Nadu, India
3 Department of Ophthalmology, RIO GOH, Chennai, Tamil Nadu, India
4 Department of Ophthalmology, Sundar Eye Clinic, Chennai, Tamil Nadu, India

Correspondence Address:
Dr. Sharmila Devi Vadivelu
Department of Ophthalmology, RIO GOH, Chennai, Tamil Nadu


Severe acute respiratory syndrome- coronavirus-2 is an enveloped, single-stranded RNA virus that causes novel coronavirus disease 2019 (COVID-19). It is highly transmissible and has a significant fatality rate, especially in the elderly and those with comorbidities such as immunosuppression, respiratory disease, and diabetes mellitus. The purpose of this brief review is to summarize those published studies as of early May 2020 on COVID in ophthalmology and to present a review of various national and international ophthalmological society guidelines, hoping to make a contribution for protecting ophthalmologists and patients.

How to cite this article:
Fredrick T N, Ariga M, Vadivelu SD, Dorairajan R, Jambagi AL. COVID -19 and ophthalmic practice.TNOA J Ophthalmic Sci Res 2020;58:81-88

How to cite this URL:
Fredrick T N, Ariga M, Vadivelu SD, Dorairajan R, Jambagi AL. COVID -19 and ophthalmic practice. TNOA J Ophthalmic Sci Res [serial online] 2020 [cited 2023 Feb 5 ];58:81-88
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Full Text


Severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 is an enveloped, single-stranded RNA virus that causes novel coronavirus disease 2019 (COVID-19). It is highly transmissible and has a significant fatality rate, especially in the elderly and those with comorbidities such as immunosuppression, respiratory disease, and diabetes mellitus. The virus has an incubation period of 2–14 days.[1],[2],[3] Initial symptoms include fever, dry cough, breathlessness, and loss of smell, and there may be gastrointestinal symptoms.[4] Although most cases appear to be mild, all of them admitted in the hospitals have pneumonia with infiltrates on chest X-ray and computed tomographic scans show patchy shadows or ground-glass opacities in the lungs. The mortality is said to be mostly due to acute respiratory distress syndrome, acute kidney injury, myocardial injury, and septic shock.[4] SARS-CoV-2 seems to have a higher infectivity but a lower mortality rate than SARS-CoV.[5] The median age of the patients is reported to be between 49 and 56 years. Males seem to be more affected than women.

The World Health Organization (WHO) has suggested that human-to-human transmission of COVID-19 occurs through droplets, contact, and fomites, similar to SARS.[6] Touching the eyes, nose, or mouth after contacting the contaminated items is likely to cause human infection.[7]

We searched PubMed from January to April 2020 for all published articles regarding ophthalmology and SARS-CoV-2. Keywords used were SARS-CoV-2, ophthalmology and SARS-CoV-2, SARS-CoV-2 in tears, conjunctivitis, and infection control measures in ophthalmology. Royal College of Ophthalmology Guidelines, American Academy of Ophthalmology Guidelines for COVID-19, and All India Ophthalmic Society-Indian Journal of Ophthalmology (AIOS-IJO) Guidelines for COVID-19 were also reviewed. Relevant articles from other specialties were also reviewed from international and national journals. To ensure that this review is up to date as possible, PubMed was regularly reviewed during the preparation of the manuscript.

Risk for Ophthalmologists[4],[8]

Due to face-to-face communication with patients, frequent exposure to tears and ocular discharge, and the use of equipment such as slit lamp, tonometer, and laser, ophthalmologists could carry higher risks of contracting a SARS-CoV-2 infection.[9] Many past studies during the previous SARS epidemic indicate that while ocular complications are not a frequent manifestation of CoV infections in humans, ocular exposure may represent a meaningful route of entry for this virus. The host epithelial cell bears receptors that are distributed throughout the human respiratory tract and ocular tissue, and it helps in the entry of respiratory viruses.

Human influenza viruses prefer α2-6-linked sialic acid in the upper respiratory tract, avian influenza viruses preferentially bind to α2-3-linked sialic acid in the lower respiratory tract, adenovirus serotypes use α2-3-linked sialic acid,[10] while SARS-CoV uses angiotensin-converting enzyme 2 (ACE 2) receptor. This ACE 2 receptor has been detected in the human retina, vascularized retinal pigment epithelium, and choroid and conjunctival epithelia.[11] The nasolacrimal system that provides an anatomical bridge between ocular and respiratory tissues bears both sialic acid receptor.[11] Conjunctivitis can also be a presenting symptom of COVID-19.[8],[12] Patients with COVID-19 conjunctivitis have the transmissible virus in the tears.[13],[14] Transconjunctival aerosol infection is a known mode of disease transmission.[8],[12] This has particular relevance to ophthalmic tests and procedures where there is contact with the tear film such as tonometry, gonioscopy, and laser procedures. Many human respiratory viruses have shown documented ocular complications [Figure 1].[15]{Figure 1}


In a retrospective case series, 12 of 38 “clinically confirmed” hospitalized cases of COVID-19 in Hubei Province, China, had ocular “abnormalities,” characterized most commonly as chemosis and/or secretions. Two patients had a positive conjunctival swab for SARS-CoV-2 RNA, one with signs of conjunctival hyperemia and the other with chemosis and epiphora.[13] In a case report in China, a confirmed case of COVID-19 with bilateral acute follicular conjunctivitis with conjunctival swab showing virus on rapid test-polymerase chain reaction (RT-PCR) was treated with topical ribavirin and swab turned negative after 10 days.[16] In another case series in China, conjunctival smear with RT-PCR for 67 COVID-19-positive patients revealed one positive and two probably positive for the presence of virus, with another patient in the same group with conjunctivitis and chemosis testing negative for the virus.[17]

Asymptomatic patients with COVID-19 or patients in incubation can transmit the disease.[18] At this point in the COVID-19 pandemic, practically, any patient seen by an ophthalmologist could be infected with SARS-CoV-2, regardless of presenting diagnosis, risk factors, indication for visit, or geographic location. Close contact during ophthalmic procedures has the risk of patient-to-ophthalmologist disease transmission.

 Control Measures to Prevent Infection

To prevent transmission in an eye hospital, Hong Kong has adopted a three-level hierarchy of control measures – administrative, environmental, and use of personal protective equipment (PPE).[19]

At the administrative level

Measures should be taken to lower patient attendance and suspend elective clinical services.[19] Waiting room overcrowding was controlled by restricting the number of patient attendants to one each. Patient triage system should be introduced, and since fever is the most common symptom, all patients and their attendants should be screened with noncontact/infrared thermometers. Elicit a history of travel to affected areas during the incubation period, occupation, contact of suspected or confirmed cases, cluster of cases, and respiratory symptoms. Information posters and awareness messages can be set up. International patients were advised to reschedule their appointment by 4–6 weeks. It was advised to avoid endoscopic dacryocystorhinostomy and general anesthesia (GA) as endotracheal intubation is of aerosol-generating nature. If unavoidable, suggested to use PPE during the procedures.[20] Noncontact tonometry (NCT) disrupts the tear film with the pulse of pressurized air and is a potential source of micro-aerosol, and hence, other modes of intraocular pressure measurement, such as iCare tonometry with disposable tips or Goldmann applanation tonometry, should be used instead.[18]

Environmental control

Apart from the regular hospital infection control (HIC) process, the following air-conditioning parameters may be considered while working in the hospital/clinic.

Temperature and humidity control – maintain 23°–27° humidity – relative humidity of 55 ± 15 RHAir exchange – Maximum clean fresh air possiblePurification of air-additional filters such as high efficiency particulate air (HEPA) or nanofilters.

Regular decontamination and disinfection process before examination/procedure surgery and optimal, rational use of appropriate PPE is more important.

Ventilation in waiting areas should be enhanced with HEPA.[20]

To lower the risk of droplet transmission, a protective shield is installed on slit lamps.[21] Equipment such as slit lamps, ophthalmoscopes, retinoscopes, computers, and doorknobs that were frequently touched by the staff should be disinfected as per the local disinfection guidelines.[19]

Use of personal protective equipment

All personnel in the hospital are asked to use N95 facemasks and instructed to practice hand hygiene by handwashing as recommended by the WHO.[21] All clinical staff was suggested to use eye protection glasses.

In ophthalmology practice, we come into close contact with the patient. Although the likelihood of the virus transmission via the respiratory tract is more than that through the eye,[22] the aerosol-generating procedures (AGPs) in ophthalmology do carry a considerable risk.

The authors also recommend the members to go through the AIOS-IJO consensus statement on preferred practices during the COVID-19 pandemic published on April 20, 2020, and the Indian Society of heating, Refrigeration and Air-conditioning Engineers COVID-19 ISHRAE guidelines for air-conditioning and ventilation for healthcare facilities.

Aerosol-Generating Procedures in Ophthalmology[23]

It is clear that aerosols generated from some nonophthalmic procedures from the upper respiratory tract, including the mouth, throat, nose, and sinuses, are definitely a high risk for generating infective aerosols that can transmit COVID-19 to those who inhale it. In addition to NCT, it is widely agreed that adnexal procedures involving the lacrimal and nasal mucosa fulfill the criteria for high-risk AGP. There is some concern that intraocular surgery using high-speed devices such as vitrectomy and phacoemulsification is AGP. Even though risk of aerosol production is possible, it is done under sterile conditions, after povidone usage and intraocularly under viscoelastics and balanced salt solution (BSS). There is some evidence that normal breathing and talking generate aerosols, but it is uncertain whether these are dangerous to those remaining near the patient for some time. As an added precaution, it is better to advise less talking and limit the movement of people in operation theater (OT)

Case Definition[24]

A suspected case of COVID-19 as per the Indian Council for Medical Research (ICMR) definitions is:

All symptomatic individuals who have undertaken international travel in the last 14 daysAll symptomatic contacts of laboratory-confirmed casesAll symptomatic healthcare workers (HCW)Asymptomatic direct and high-risk contacts of a confirmed case (should be tested once between day 5 and day 14 after contact)All hospitalized patients with severe acute respiratory illness (fever, cough, and shortness of breath).

A confirmed case is a person with laboratory confirmation of COVID-19 infection, irrespective of clinical signs and symptoms. Patients meeting the above criteria must be immediately notified to both infection control personnel at your healthcare facility and your local or state health department for further investigation of COVID-19 as per the Government of India-ICMR guidelines.

Environmental Cleaning and Disinfection Recommendations[25]

Rooms and instruments should be thoroughly disinfected after each patient encounter. Slit lamps including controls and accompanying breath shields should be disinfected, particularly wherever patients put their hands and face. The current Communicable Diseases Control recommendations[25] for disinfectants specific to COVID-19 include:

Sodium hypochlorite 0.5%–1% – preferable freshly prepared everydayAlcohol solutions with at least 70% isopropyl alcohol.

Interim Guidance from American Academy of Ophthalmology for Triage of Ophthalmology Patients [Table 1][13]{Table 1}

Personal protective equipment

PPEs are protective equipment designed to safeguard the health of workers by minimizing the exposure to a biological agent.

The Ministry of Health and Family Welfare department has given recommendations for PPE at different levels [Table 2], [Table 3], [Table 4].{Table 2}{Table 3}{Table 4}

Protocol for essential/emergency surgery/procedure [Table 2], [Table 3], [Table 4]

The resumption of services may start with emergency/essential services with a triage system and appropriate and rational use of PPE by the staff.

1. Emergency/urgent surgery

Fill COVID checklist [Figure 2]. Screening with a pulse oximeter for all patients may be considered as some are asymptomatic afebrile patientsDo COVID RT-PCR either preoperative or postoperative depending upon the time of surgeryProceed with surgery without waiting for COVID report, with full COVID precautions in OTIf symptom checklist is positive, shift to COVID ward/isolation room postoperative, and involve physician on-callIf symptom checklist is negative, shift to single room postoperative and follow droplet and contact precautions till COVID PCR is reported negative twice.{Figure 2}

2. Essential surgery

Fill COVID checklist [Figure 2]If COVID checklist is one or more positive, defer surgery for 2 weeks and refer to physician/fever clinicIf COVID checklist is negative, do preoperative COVID RT-PCR testing as outpatient or inpatientComputed tomography chest is optional (as per discretion of the physician), to be avoided in children and pregnancy


Ensure COVID declaration form has been filled by the patient [Figure 3]If patient needs to be shifted to the ward, maintain 6 ft distance between each bed and follow droplet precautions.{Figure 3}

Theater protocols[27]

Many of our understanding of COVID-19 is from the study of SARS epidemic and is extrapolated to COVID-19. HIC practices for emergency and planned surgeries are evolving with experience from China, Italy, US, and other countries, where pandemic has advanced to the next level. Patients with COVID-19 infection may have to undergo elective or emergency surgical procedures under local anesthesia or GA.

The basic concept of infection prevention and control (IPC) norms in OT is to consider all patients' body fluids as infectious and follow universal precautions (National Guidelines for IPC). COVID-19 may add another perspective to the existing guidelines.

The guidelines that need to be followed after lockdown and before starting the OT are:

Complete overhaul cleaning of entire OT complex and fumigation must be done with a nonformaldehyde-based solutionPerform three culture sensitivity sampling (air sampling/surface swabs) for aerobic/anaerobic/fungal cultures with 3–5 days apart in all OT zonesActive air sampling is preferred over passive air sampling for air handling unit (AHU) OTsRestart OT only after all swab samples are reported negativeParticulate count for OT with AHU/HEPA filter should follow ISO Class 6 standardsTerminal ultra-low particulate air filters and ultraviolet lights in prefilter chambers must be installed (optional)Due to SARS-CoV-2 situation, serology-positive protocol in OT for all surgeries irrespective of their status should be maintainedPerform RT-PCR for SARS CoV-2 for high-risk patients and patients requiring GAAll OT personnel including surgeon to use PPE as per the guidelines. Patient should wear a cap and a mask and appropriate theater dressThere should be a dedicated donning area adjacent to the scrub room. There should be a separate doffing room with hand sanitation facility and waste collection bins (Preferable)Cover all equipment with sterile nonwoven paper cover during operation to prevent aerosol depositionOT cleaning/biomedical waste (BMW) disposal should be done after each surgeryCleaning of OT/furniture/instruments should be done after each caseOnly one case should be operated in an OT at a timeIf more than a case is planned, the entire OT has to be cleaned (in case of nonheating ventilation air-conditioned HEPA-filtered OT) and then the second case has to be resumed after thorough disinfectionSurgical team should also be screened with preliminary questionnaire and thermal screening for fever every day. They should undergo risk assessment every day for COVID symptoms based on questionnaire and declaration to be obtainedSurgical team should rescrub and change to appropriate PPE after each surgical caseUsed instruments/BMW should be removed out of OT immediately after each caseAGPs are to be done safely with all precautions (GA/orbital surgeries, and any surgery needing suction)Soiled linen used should be packed separately and labeled as blood and body fluids (BBF). Personnel handling these should use proper PPEAll BMW should be labeled as “BBF” and disposed as per the protocol within 48 h from the premisesAvoid sharing any consumables such as BSS and viscoelastic devicePhaco hand-piece, irrigating aspiration handiece, sleeves, phacoemulsification tips, and tubing should be sterilized for each caseUse of disposables is recommended but not mandatoryMinimum staff should be present inside OT and persons inside OT should not go outside during the procedureEach OT zone should have separate staff and multitask approach should be avoided in the OT complex.


The above document is an advisory based on the current literature, resources, and expert opinion. Important clinical data and disease patterns of SARS-CoV-2 are evolving and we are still a long way to understand the virus transmission, pathogenicity, and risk to the surgical patient and the surgical team. The COVID-19 pandemic has disrupted our daily life and ophthalmic practice. We can only bounce back from this if we follow due diligence, maintain a good triage system to closely watch out for patients with possible infection, and take specific measures to protect ourselves and our patients. In this review article, we have extensively reviewed, have summarized, and have provided some guidelines issued by various health authorities for your perusal. The guidelines mentioned here reflect the best available information at the time this article was prepared. The guidelines are evolving and issued regularly, and we will be constantly updating it. If these are inculcated and strictly adhered to, we can minimize further damage and get back to our routine practice as soon as the disease subsides.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


1Khan S, Siddique R, Ali A, Xue M, Nabi G. Novel coronavirus, poor quarantine, and the risk of pandemic. J Hosp Infect 2020;104:449-50.
2Centers for Disease Control and Prevention. Available from: [Last accessed on 2020 Apr 13].
3Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, et al. Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia. N Engl J Med 2020;382:1199-207.
4Jiang F, Deng L, Zhang L, Cai Y, Cheung CW, Xia Z. Review of the clinical characteristics of coronavirus disease 2019 (COVID19). J Gen Int Med 2020;35:1545-9.
5Paules CI, Marston HD, Fauci AS. Coronavirus infectionsmore than just the common cold. JAMA 2020;323:707–8. [doi: 10.1001/jama. 2020.0757].
6World Health Organization. Coronavirus Disease Pandemic. Available from: [Last accessed on 2020 Apr 13].
7Han Q, Lin Q, Ni Z, You L. Uncertainties about the transmission routes of 2019 novel coronavirus. Influenza and other respiratory viruses. Influenza Other Respir Viruses 2020;1-7. [doi: 10.1111/irv. 12735].
8American Academy of Ophthalmology. Available from: [Last accessed on 2020 Apr 13].
9Yu AY, Tu R, Shao X, Pan A, Zhou K, Huang J. A comprehensive Chinese experience against SARS-CoV-2 in ophthalmology. Eye Vis (Lond) 2020;7:19.
10Kumlin U, Olofsson S, Dimock K, Arnberg N. Sialic acid tissue distribution and influenza virus tropism. Influenza Other Respi Viruses 2008;2:147-54.
11Sun LL, Pan X, Jing M. Mechanism of the action between the SARS-CoV S240 protein and the ACE2 receptor in eyes. J Virol 2006;6:783-6.
12Lu CW, Liu XF, Jia ZF. 2019nCoV transmission through the ocular surface must not be ignored. Lancet (London, England) 2020;395:e39.
13American Academy of Ophthalmology. Important Coronavirus Updates for ophthalmologists. Available from: [Last accessed on 2020 Mar 13].
14Xia J, Tong J, Liu M, Shen Y, Guo D. Evaluation of coronavirus in tears and conjunctival secretions of patients with SARSCoV2 infection. J Med Virol 2020;92:589-94. [doi: 10.1002/jmv.25725].
15Belser JA, Rota PA, Tumpey TM. Ocular tropism of respiratory viruses. Microbiol Mol Biol Rev 2013;77:144-56.
16Chen L, Liu M, Zhang Z, Qiao K, Huang T, Chen M, et al. Ocular manifestations of a hospitalised patient with confirmed 2019 novel coronavirus disease. Br J Ophthalmol 2020. [doi: 10.1136/bjophthalmol-2020-316304].
17Zhou Y, Zeng Y, Tong Y, Chen CZ. Ophthalmologic Evidence Against the Interpersonal Transmission of 2019 Novel Coronavirus Through Conjunctiva; 2020. doi:
18Chang D, Xu H, Rebaza A, Sharma L, Cruz CS. Protecting healthcare workers from subclinical coronavirus infection. Lancet Respir Med 2020;8:e13.
19Lai TH, Tang EW, Chau SK, Fung KS, Li KK. Stepping up infection control measures in ophthalmology during the novel coronavirus outbreak: An experience from Hong Kong. Graefes Arch Clin Exp Ophthalmol 2020;258:1049-55.
20Tran K, Cimon K, Severn M, Pessoa-Silva CL, Conly J. Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: A systematic review. PLoS One 2012;7:e35797.
21World Health Organization. Available from: [Last accessed on 2020 Mar 13].
22Sadhu S, Agrawal R, Pyare R, Pavesio C, Zierhut M, Khatri A, et al. COVID-19: Limiting the risks for eye care professionals. Ocul Immunol Inflamm 2020;1-7. [].
23The Royal College of Ophthalmologists RCOphth COVID-19 Clinical Guidance and National Information. Available from: [Last accessed on 2020 Apr 28].
24Ministry of Health and Family Welfare, Government of India. Guidelines for Notifying COVID-19 Affected Persons by Private Institutions. Available from: utions.pdf. [Last accessed on 2020 Apr 20].
25Centers for Disease Control and Prevention. Information for Healthcare Professionals about Coronavirus. Available from: [Last accessed on 2020 May 04].
26Ministry of Health and Family Welfare Directorate General of Health Services. Novel Coronavirus Disease 2019 (COVID-19): Additional Guidelines on Rational use of Personal Protective Equipment (Setting Approach for Health Functionaries Working in Non-COVID Areas). Ministry of Health and Family Welfare Directorate General of Health Services. 2020.
27Ministry of Health and Family Welfare Government of India. National Guidelines for Infection Prevention and Control in Healthcare Facilities. Available from: (1).pdf. [Last accessed on 2020 May 09].