New challenges and workaround: Ultrasound biomicroscopy in time of COVID-19 pandemic.

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.