ASCRS News: EyeSustain Update
Fall 2025
Have you ever wondered why your institution may insist on disposable gonioscopy lenses, B-scan ultrasound probes, or tonometry tips? The alternative is sterilization practices that are not evidence-based, may lead to device destruction, and create a massive amount of medical waste. In the name of patient safety, regulatory bodies impose classifications and cleaning specifications on devices in all specialties in medicine. In this EyeSustain Update column, we feature a conversation with Irene Kuo, MD, cornea specialist and associate professor of ophthalmology at Wilmer Eye Institute, in Baltimore, Maryland, regarding her special report, “Disinfection of outpatient ophthalmic devices: a critique of ‘semicritical’ designation.”1
—Emily Schehlein, MD, EyeSustain Update Guest Editor
In your report, you discuss how the U.S. FDA and Centers for Disease Control and Prevention (CDC) follow the Spaulding classification for medical devices and instruments across specialties. Can you discuss the Spaulding classification and why this system may not be aligned with mitigating infection risk in modern ophthalmology?
Irene Kuo, MD: The Spaulding classification dates to the 1930s, when microbiologist Spaulding came up with a system to categorize the disinfection or sterilization needed for reusable medical devices and surgical instruments to mitigate the potential risk of infection posed to the next patient.
While the Spaulding classification may have worked for decades and was a good framework (such that regulatory agencies continue to adhere to it), it needs to be updated, and/or ophthalmic devices must be separated into their own category. In the 1930s, the ophthalmic landscape was relatively primitive—no microscopes, no phacoemulsification, no corneal transplants, no lasers, no ultrasounds. Spaulding and others at regulatory agencies classify the whole of the eye as a “mucous membrane,” which it is not, nor is it as contaminated as, for example, the colon, with which the eye is lumped as a “mucous membrane.” By this classification, ophthalmic equipment—such as ultrasound probes, laser lenses, and applanation tips—must undergo high-level disinfection or sterilization the way colonoscopes and anal manometers must. By contrast, blood pressure cuffs and stethoscopes are classified as non-critical, by contacting intact skin. Interestingly, the conjunctiva and cornea are cleaner than skin, yet devices that contact them must undergo a higher level of disinfection by the Spaulding classification. This is where institutions fault ophthalmology departments for not following manufacturer “instructions for use” (IFU) on disinfection.
You also discuss the difficulties of performing high-level disinfection (HLD) on ophthalmic devices (and the frequency of HLD, which is low in academic centers and likely non-existent in private practice). Can you expand upon the challenges to ophthalmology clinics posed by this push for HLD?
Dr. Kuo: First, as a specialty (along with David F. Chang, MD, I am leading an HLD task force consisting of reps from various ophthalmic societies), we need to push back because HLD for our equipment is neither science- nor evidence-based. For example, HLD varies by geographic location. Already, that is a problem when our devices are made by multinational corporations. Does that mean HLD has to be different in each country they sell to?
Companies with disinfectant products can conduct studies on bacteria they choose and claim that their product qualifies as HLD. For certain, companies do not have any obligation to show that HLD is better than any methods we ophthalmologists currently use in our clinics to disinfect our lenses, ultrasound probes, or applanation tips. Lastly, there is no obligation that manufacturers show that highly delicate (and expensive) ophthalmic devices can withstand multiple exposures to HLD. This issue gets at the cross purposes of business interests (manufacturers of devices, companies that make disinfectant products or devices) and clinical care, and business interests and sustainability. Do we really need to buy $1 million more ultrasound probes because performing HLD will take our instruments out of service for a certain number of hours or days? This cost estimate does not even get at labor or HLD storage costs.
You discuss regulators and how their assumption of “worst case” scenarios, for example with tonometry tips and prion disease, can lead to significant waste production and emissions. Can you outline this for our readers?
Dr. Kuo: It is somewhat understandable from a risk perspective for regulators to look at worst case scenarios. Despite questionable study design, a few studies have been cited by regulators that applanation can spread prion disease, and these studies do not show that at all. We may be performing applanation on patients harboring prion disease, but truly no HLD is effective against prions—whether on an applanation tip, in a colonoscope or a bronchoscope. At some point, the regulation becomes onerous and not based on common sense. There is no evidence HLD is better at reducing the rate of infection transmission between YAG laser patients. Is it possible HLD reduces bacterial counts more than an alcohol wipe in a lab experiment? Yes. But in a clinical environment, with the antimicrobial factors in the tear film and the mechanical cleaning of laser lenses and ultrasound probes, does that translate to infection risk that rises to any threshold we clinicians should be concerned about? To date, there is no evidence in the literature of transmission of any infection attributed to reusable ultrasound probes, laser lenses, or applanation tips.
Bowing to regulation leads to significant waste (the move to single-use laser lenses and applanation tips and/or HLD for these pieces of equipment). It also begets lower quality of clinical care if these devices are lower quality than reusable ones or the reusable lenses become damaged with repeated HLD.
The article opens with a discussion of the 2014 policy from the Centers for Medicare & Medicaid Services (CMS) preventing short cycle sterilization, which prompted ophthalmic studies showing this is a safe practice and the Ophthalmic Instrument Cleaning and Sterilization (OICS) Task Force to issue specialty-specific regulations. How can ophthalmologists use this as an example to shape evidence-based, sustainable disinfection protocols for ophthalmic devices moving forward?
Dr. Kuo: We must thank David F. Chang, MD, Nick Mamalis, MD, and the other members of the OICS Task Force for the tremendous work they did to present to regulators that the tissue burden is different for the eye—in their words, regulatory guidelines from outside ophthalmology “often do not take into account the unique conditions of intraocular surgery and special requirements for cleaning and sterilizing ophthalmic instrumentation. As a result, all-inclusive, broad guidelines attempting to cover surgery from head to toe could sometimes include inappropriate, or even risky, practices for ophthalmic cases.”
The Task Force showed not only that short-cycle sterilization is appropriate for sequential, same-day instrument reuse but also that instructions for use that required enzymatic detergents for decontaminating intraocular surgical instruments could damage the eye. Note, the Task Force did not say one must stop using enzyme cleaners, but it made the point that manufacturer IFUs are not always safe and certainly not always based on the risk posed to patients in real-life practice.
Regulators need to value the point of view of us end users who perform surgery and conduct clinical care. In the end, experiments performed on other body parts or attempts to simulate the potential for an applanation tip to spread adenovirus by culturing steel discs exposed to a solution of adenovirus are just not helpful. I think ophthalmology, being a small but highly important specialty, can help our patients by educating regulators, some of whom are MDs or PhDs with little exposure to or knowledge about ophthalmology.
Reference
- Kuo IC. Disinfection of outpatient ophthalmic devices: a critique of “semicritical” designation. J Cataract Refract Surg. 2025;51:355–358.
Relevant disclosures
Kuo: None
Contact
Kuo: ickuo@jhmi.edu
