Face masks on patients may contribute to endophthalmitis risk
Patients wearing face masks during intravitreal injections may be at a higher risk of endophthalmitis, according to a study.
“Rather than provide an extra protection, as we would think from the lesson learned from COVID-19, they could represent a risk during ocular procedures,” Amir Hadayer, MD, told Healio/OSN.
Hadayer and colleagues at Rabin Medical Center, affiliated with Tel-Aviv University in Israel, used thermal cameras to show that face masks deviate exhaled air toward the eyes.
“When not mechanically blocked, the exhaled air tends to move forward, away from the mouth and nose. But the face mask redirects it toward the eyes, contaminating the surgical field. This is a very important piece of information we want to share with colleagues,” Hadayer said.
Wearing face masks is important for patients from the moment they walk into clinics to protect themselves and others from SARS-CoV-2 infection. Common sense would suggest that they continue wearing them during intravitreal injections for the same reason, but this habit, newly adopted by several clinics in the COVID-19 era, can have detrimental consequences if additional safety measures are not implemented, according to the study published in Retina.
Study with thermal and gas imaging cameras
“Our study preceded the COVID-19 era because we hypothesized some time ago that surgical masks should be worn not only by the surgeon but also by the patient during intravitreal injections. The bacteria that cause endophthalmitis can originate from the surgeon but also from the patients themselves, and we thought that wearing a mask might provide further protection,” Hadayer said.
However, because every change requires careful consideration of potential drawbacks, doubt immediately arose that this might not be such a good idea after all. A study was therefore set up to investigate the safety of wearing face masks during intravitreal injections. Three types of face masks were used, including regular face masks with four tying strips (FarStar Medical) or elastic ear loops (Mediplus) and the 2200 N95 tuberculosis particulate face mask (Moldex). Ten healthy volunteers were asked to wear the masks over several consecutive sessions, in which detection of air leak was performed using two professional thermal cameras, the FLIR A310 and the Opgal EyeCGas 2.0 super-sensitive gas imaging camera.
“Air jets originating from the superior edges of the masks and radiating toward the eyes were detected in 81% of the cases with all three types of masks,” Hadayer said.
While the air is normally blown forward, face masks block it and redirect it toward the eyes.
“The clinical interpretation of this finding is that when patients wear surgical face masks during intravitreal injections, the risk of surgical field contamination is paradoxically increased,” the authors said.
“Anyone who works with microscopes and glasses knows that face masks make the air go up and cause fogging of the lenses,” Hadayer said. “It is like blowing air inside the patient’s eye, so the sterile field is not sterile anymore.”
Recommendations for safe injections
“What we learned from this study preserved us from making the mistake of performing injections on patients wearing face masks as we entered the COVID era. Other hospitals in Israel had meanwhile been alerted, and since our paper was published, we have received messages from colleagues in different parts of the world saying they had immediately changed their practices,” Hadayer said.
To provide safe injections without risking exposure to SARS-CoV-2 infection, Hadayer and co-authors suggested draping the eye with a surgical adhesive drape without removing the mask.
“We prep the periocular area with a solution of povidone-iodine, dry the place very well, then apply a surgical drape to isolate the eye from the mouth and nose, and finally insert an eyelid speculum to keep the eye open and prevent contact of the eyelid with the needle. We put a drop of povidone-iodine into the conjunctival sac and do the injection,” Hadayer said.
Protocols for preparing patients for intravitreal injections vary, and not all specialists use draping and a speculum in normal times, but under the current circumstances, these extra precautions are recommended, in Hadayer’s opinion.
“If you don’t have the surgical drape available, another simple way of preventing air jets from contaminating the surgical field is to apply a medical adhesive tape on the upper border of the face mask to block the passage of air,” he said.
The study was technically complicated, involving the use of expensive professional equipment and complex processes to get all of the necessary approvals, but it was worth the effort, Hadayer said, because people had to be warned of this potential problem. On the other hand, precautions are simple, easy to adopt and “hopefully” will be included in future guidelines.
“We hope that our message will spread widely and fast because this could potentially save many patients from losing vision. I feel privileged to be part of a group that hopefully will make a change. This is our task, after all, as doctors and researchers,” Hadayer said.
For more information:
Amir Hadayer, MD, can be reached at Department of Ophthalmology, Rabin Medical Center, Beilinson Hospital, 39 Jabotinsky St., Petah Tikva 4941020, Israel; email: email@example.com.