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Toxic Anterior Segment Syndrome: Are We Ever out of the Woods? (part 3)
By Sara Freiberg

Questions surrounding additional risk factors which may contribute toward TASS are worth noting. Lawrence F. Muscarella, PhD, has written an interesting article featured in The journal of American Society of Ophthalmic Registered Nurses (ASORN) INSIGHT magazine, which discusses these very questions. Through his research, Dr. Muscarella brings to light that enzymatic detergents used to clean intraocular surgical instruments have not been documented as either a primary cause or a significant contributor to TASS.Dr. Muscarella shares additional risk factors for TASS may be identified, including bacterial contamination of water reservoirs in steam sterilizers, immediate use steam sterilization, as well as potential damages on ophthalmic instruments.

Ultrasonic cleaning
Ultrasonic cleaning is powerful when used correctly and according to the ultrasonic and ophthalmic instrument IFUsIf ultrasonic cleaning is stated in the IFU, facilities should follow strict adherence to the instructions to avoid the potential of TASS. There are reports of ultrasonic units that contained endotoxins due to facilities that do not change the ultrasonic bath as recommended per the ultrasonic IFU.

Manufacturers also recommend against mixing dissimilar metals or mixing ophthalmic instruments along with other surgical instrumentation while in the ultrasonic cleaner. Additionally, some ophthalmic instrument IFUs state facilities should strongly consider using a dedicated ultrasonic bath for ophthalmic surgical instruments only.

Steam sterilizers and water impurities
Mirroring Dr. Muscarella’s points, impurities have been uncovered in the water supply of steam sterilizers and investigations have identified the presence of impurities such as sulfates, copper, zinc, nickel, and silica in steam moisture, attributing to the improper or lack of proper maintenance of the steam sterilizer. A Mayo Clinic study on TASS revealed, “…once the (steam) impurities were eliminated, no further cases of TASS were observed.”2

The quality of the water used to generate steam is important for the success of sterilization. Water for steam must be treated to remove minerals and other contaminants as close to 100% saturated steam as possible. AAMI ST79 L.2 states steam dryness should be at a value between 97% and 100%, and the level of noncondensable gas should be at a level where it will not impair steam penetration into sterilization loads.Impurities, through time and use, may accumulate various deposits inside the chamber walls, including poor water quality, detergents, tape, and stickers, which can contaminate packs, transfer onto surgical instruments, and affect autoclave performance. Organic residue and inorganic salts can also interfere with the sterilization process and act as a barrier to the sterilization agent. Manufacturer IFUs, AAMI ST79, AORN, and the CDC recommend regular sterilizer chamber cleaning in the equipment maintenance supplement to ensure that the sterilizer continues to perform according to the manufacturer’s validated specifications.

Immediate Use Steam Sterilization (IUSS)
AAMI ST79 refers to IUSS as a “sterilization method that involves the shortest possible time between a sterilized item’s removal from the sterilizer and its aseptic transfer to the sterile field. Immediacy implies that a sterilized item is used during the procedure for which it was sterilized and in a manner that minimizes its exposure to air and other environmental contaminants. A sterilized item intended for immediate use is not stored for future use nor held from one case to another.”4

IUSS is not acceptable as a routine method of sterilization. Per the guidelines, IUSS should never be used for the sake of convenience or lack of instrumentation and, more importantly, it should be used in emergency situations only.

In 2015, the Centers for Medicare and Medicaid Services (CMS) created Guidelines for the Cleaning and Sterilization of Intraocular Surgical Instruments. A short cycle sterilization was deemedappropriate as well as clarified to the healthcare community. It was emphasized that IUSS is not the same thing as short cycle sterilization. CMS stated, “Short cycle sterilization is a form of terminal sterilization that is acceptable for routine use for a wrapped/contained load where precleaning of instruments is performed according to the manufacturers’ instructions and the load meets the device manufacturer’s instructions for use (IFU), includes use of a complete dry time, and is packaged in a wrap or rigid sterilization container validated for later use. CMS stated ‘use of short cycle sterilization…is acceptable when all IFUs (i.e., sterilizer, device, and container manufacturers) are followed.’”5

The term “short cycle” stated as “a form of terminal sterilization” could potentially cause confusion among the healthcare community.

Dr. Simon Holland, M.D., a clinical professor at The University of British Columbia, experienced an outbreak at his facility relating to endotoxin contamination. In 2007, when the term “flashing” was still in use (now termed IUSS), Dr. Holland stated, “If you’re short of time or you’re flashing instru­ments, then it can certainly kill bacteria, but it doesn’t deactivate endotoxin. If you get a sufficient load of endotoxin in a susceptible individual, you can get TASS.”6

Following the outbreak, many changes were made at Dr. Holland’s center. “We tried to improve the ultrasound, we removed detergents, we made multiple changes to draping techniques, we replaced cannulated instruments where possible behind the small cannulas and got disposable only, and still it continued.” The outbreak ended when the staff limited short cycle sterilization and found bacterial growth in the sterilizer reservoir. “Once we cleaned that up, we had no further cases of TASS in two years now,” he said.

Dr. Holland recommends facilities use a proactive approach, “…to allow enough time between cases for the surgical processing department to have the time to really clean the instruments thoroughly, as well as double-checking with the cleaning staff to find out what is happening.”7

The prevention of TASS still continues and is highly dependent upon the careful monitoring and performance of numerous processes, products, and systems before, during, and after anterior segment surgery. Departments performing anterior segment procedures should incorporate a written policy that’s in accordance with the manufacturers’ instructions and the regulatory guidelines. Sharing the prevention of TASS with our healthcare teams is imperative. Allowing staff the necessary time that it takes to ensure each and every step is being meticulously followed will help contribute to patient safety and positive surgical outcomes.


  1. https://www.lfm-hcs.com/2018/03/are-enzymatic-detergents-the-primary-cause-of-the-inflammatory-eye-reaction-called-tass/
  2. https://mayoclinic.pure.elsevier.com/en/publications/outbreak-of-toxic-anterior-segment-syndrome-following-cataract-su
  3. AAMI ST79
  4. AAMI ST79
  5. http://ascrs.org/node/21433
  6. https://www.eyeworld.org/article-update-o
  7. https://www.eyeworld.org/article-update-o

Additional Resources
The TASS Task Force has implemented an effort to educate hospitals. If your facility experiences an ongoing concern or outbreak, the TASS Task Force is a great resource helping facilities get to the root of the issue. The TASS Task Force has developed two main questionnaires used in evaluating all TASS cases:

  • Medications and fluids used during cataract surgery
  • Cleaning and sterilization of ophthalmic instruments


In addition to the ophthalmic surgical instrument IFU, the American Society of Ophthalmic Registered Nurses (ASORN) is also a great resource for caring for ophthalmic instruments. Click here to review ASORN Cleaning Guidelines:

Additional Reported Events/Potential TASS Contributors


Patient Health

Textured and/or powdered gloves

Reuse of single-use products

Inappropriate agents used for skin prep

One-piece intraocular lenses

Ethylene oxide-sterilized vitrectomy packs







Sara Freiberg, CST, CBSPDT, CER, has more than 15 years experience working as a certified surgical technologist, with five of those years spent traveling to various operating rooms across the U.S. Following Sara’s time in the clinical arena, she worked as a surgical technology didactic and lab instructor at Rasmussen College. Sara holds bachelor degrees in science and business and marketing, which led to her work with various medical device companies as a clinical specialist, product manager, and clinical training manager. She has experience working on quality and regulatory teams, monitoring patient-adverse events, and postmarket surveillance activities.

Sara currently works for Northfield Medical as a clinical education manager where she provides education which is based on current manufacturer and regulatory guidelines regarding various healthcare topics for SPD, OR, and GI staff. Training entails the care and handling of medical devices to ensure patient safety, as well as targeted education addressing departmental cost concerns. Her passion is working with SPD, OR, and GI departments; providing assessments; and sharing best practices with respect to patient and staff safety, surgical instruments, and medical devices. Sara is a voting member of the AAMI ST/WG84, ST91 flexible endoscope committee, and she has developed several CEU presentations approved through CBSPD, CBRN, NCCT, and IAHCSMM. Sara also authors a biweekly healthcare article for Ultra Clean Systems.

Sara is currently studying for the Certification Infection Control (CIC) exam through APIC.

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