Dear Editor:
Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infection associated respiratory disease – COVID-19 (2019-nCoV) is currently a pandemic involving more than 151,767 infected patients in India,[1] and over 5,404,512 cases all over the world.[2] Reports have shown the likelihood of disease transmission through the ocular secretions of patients.[3] All ocular procedures have to be undertaken focusing on protecting the patient and the medical worker. Ultrasound biomicroscopy being a high-resolution ultrasound technique which allows non-invasive in-vivo imaging of the anterior ocular segment is an inevitable investigation in ophthalmology.[4]
Technique of UBM: Ultrasound biomicroscopy is performed with patient lying in supine position. After topical anaesthesia, an eyecup is placed and is filled with a sonolucent coupling fluid to form a water bath. The probe oscillates within this open water bath.[4]
The procedure poses some risks of exposure to the examiner and the patient. We herein recommend solutions to the possible risks in Table 1.
Table 1.
Possible risks of exposure and its solutions during UBM
| Solutions | |
|---|---|
| Risk to the Examiner: Exposure to oronasopharyngeal and ocular aerosols | |
| Position: The patient is lying supine and the examiner is at the head end of the patient. Lack of Barrier: Between the patient and the examiner. Possible aerosol dispersion from open water bath: The probe oscillates in an open water bath which could lead to aerosol dispersion of the coupling medium mixed with ocular secretions. |
Use of mask: by patient Use of surgical drape: exposes only the eye to be imaged. Face shield: Wearing a face shield such that it covers the examiner’s face from below [Figure 1b]. This modification will prevent the direct exposure of aerosols from below, which is not achieved by wearing the face shield in a regular manner [Figure 1a]. N95 mask, goggles, and gloves: by examiner. |
| Risk to the patient: | |
| Contact procedure: Even though non-invasive, UBM is a contact procedure and involves inherent risks. | Perform UBM only if mandatory.[5] Use disposable tips. Can also use cut glove to cover the tip of probe and dispose after every use.[5] Ensure that air does not get trapped between the tip and glove as it affects imaging. Cups sterilization: Ethylene Oxide (EtO) sterilization after each use.[5] Probe sterilization: 70% Isopropyl alcohol, or covered with a disposable glove that can be discarded after each use.[5] Disposable water bath: that can be attached to the probe, such as, ClearScan. Avoids the risk of aerosols. Imaging is possible with patient in sitting position. |
We also made a small but significant change for the person performing the UBM as shown in [Fig. 1a and b]. It is advised that these extra steps can be implemented to safeguard our medical workers and protect our patients during these trying times.
Figure 1.
(a) Face shield covers examiner's face from front, with opening from below and the sides. (b) The same face shield worn from below; covers examiner's face from below and reduces exposure while performing UBM with patient in supine position
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
- 1. [Last accessed on 2020 May 27]. Available from: https://www.mohfw.gov.in/
- 2. [Last accessed on 2020 May 27]. Available from: https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200527- covid-19-sitrep-128.pdf?sfvrsn=11720c0a_2 .
- 3.Lu CW, Liu XF, Jia ZF. 2019-nCoV transmission through the ocular surface must not be ignored. Lancet. 2020;395:e39. doi: 10.1016/S0140-6736(20)30313-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.He M, Wang D, Jiang Y. Overview of ultrasound biomicroscopy. J Curr Glaucoma Pract. 2012;6:25–53. doi: 10.5005/jp-journals-10008-1105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Guidelines for Glaucoma Management during COVID times, Version 1.0, w.e. f. May 11th, 2020. Tejwani S, Angmo D, Nayak BK, Sharma N, Sachdev MS, Sinha R. AIOS Working Committee. Ophthalmic practice guidelines in the current context of COVID 19. All India Ophthalmological Society [Google Scholar]