Questions and Answers: Non-Contact Tonometer Safety in the COVID-19 Era
Almost 50 years since inventing the Non-Contact Tonometer, Reichert® continues to innovate and pioneer patented non-contact technologies like Corneal Compensated IOP (IOPcc), a better pressure measurement, and Corneal Hysteresis (CH), a measurement consistently shown to be a more powerful predictor of, and strongly associated with, glaucoma progression, more so than key risk factors such as IOP and CCT.A-C
Now more than ever, eye care professionals are concerned about safety, not just for their patients but also for their staff. There has been much debate on the safest way to perform routine eye exams, especially when it comes to tonometry. Reichert is here to answer your questions on the safe use of Non-Contact Tonometers, and provide up-to-date information on best practices to follow.
According to the current research, there is no material evidence that Non-Contact Tonometry is an aerosol generating procedure, and the current science shows the risk of spreading COVID-19 through tears is low and seems to be confined to patients who present with ocular symptoms.
What level of cleaning is required for a Reichert Non-Contact Tonometer?
All Reichert Non-Contact Tonometers are classified as non-critical devices because they contact intact skin, they do not contact the mucous membrane. As such, Non-Contact Tonometers require low-level disinfection.
Note: Goldmann tonometers and prisms are classified as semi-critical and require high level disinfection.
What is the proper cleaning and low-level disinfection procedure for a Non-Contact Tonometer?
Is there a risk of air tube contamination that can spread infections to other patients?
There is no evidence to suggest that contamination can enter the Non-Contact Tonometers air tube and cause harm to other patients.1
Is Non-Contact Tonometry an aerosol generating procedure (AGP)?
There is no material evidence that Non-Contact Tonometry is an aerosol generating procedure. The only publication on this subject is from 1991 by Britt et al. The authors used fluorescence photography to capture visible tear film splatter from the air puff in eyes with the application of supplemental topical fluorescein or artificial tears.1 However, this photographic method is not capable of capturing “aerosolization” as aerosols are particles that are not visible to the eye. Today, it is agreed that the authors used incorrect terminology in describing their findings as “micro-aerosolization”. It should also be noted that the air pulse technology utilized in the study applied 4 to 6 times more force than modern Non-Contact Tonometers, making the tear film splatter much more substantial.2
Is the SARS-CoV-2 virus present in tears?
The primary path of infection is through droplets produced by and entering into the mouth, nose, and lungs.3 Numerous studies evaluated the presence of SARS-CoV-2 in tears and found the risk to be low (0-5.2%) and only present in patients with ocular manifestations such as chemosis, conjunctival hyperemia, or conjunctivitis.4-6
What are the risks of spreading the virus through the eye?
It has been suggested that the eyes might be a portal of entry for the virus because of the presence of ACE receptors, but there is currently no clinical evidence for this theory (and the dermis also contains ACE receptors).7 In addition, there is no evidence that viral particles can be implanted into the eye during Non-Contact Tonometry. The air pulse generating mechanism in Reichert Non-Contact Tonometers is almost completely shielded by the plastic housing of the instrument, making it unlikely for respiratory droplets from patients or clinicians to enter the device.
Is there any evidence of infection spread by use of a Non-Contact Tonometer?
No, the Non-Contact Tonometer has a 50-year record of safety. There are no documented instances of infection being spread by use of a Non-Contact Tonometer.
Does Non-Contact Tonometry provide a safer working distance between clinician and patient, compared to other forms of tonometry?
Yes, the typical clinician-patient distance is approximately 3 feet and rarely requires the clinician to touch the eyelid.