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Toxic Anterior Segment Syndrome: Are We Ever out of the Woods? (part 2)
By Sara Freiberg

In Issue #37, we described toxic anterior segment syndrome (TASS) and looked at some of the potential contributors to TASS, including contaminated balanced salt solution (BSS) and excess ophthalmic viscosurgical devices (OVDs) used during cataract surgery. This issue, we continue our discussion of potential contributors to TASS.

Intraocular medications
Antibiotic solutions prepared for intracameral injection should be free of preservatives or other additives. The American Society for Cataract and Refractive Surgery (ASCRS) found that through various preparations of antibiotics, anesthetics, and other medications contained an incorrect pH, or contained endotoxins or preservatives that have may have contributed to TASS. Some reports included an “oily film-like material within the anterior chamber, as well as an oily bubble floating inside the anterior chamber.”1

Complex devices
Phacoemulsification handpieces are important devices used to perform cataract procedures. These handpieces have three functions: to irrigate the eye (keeping it inflated), to phacoemulsify (break up the cataract), and to aspirate (by removing debris). These are, however, complex devices with multiple internal channels and components that have the potential to retain residue if not cleaned in a timely manner; properly cleaned; rinsed, flushed, and dried, according to the device manufacturer IFU. 

Ophthalmic instrument inspection
Inspecting surgical instruments is a must. We should inspect all instruments prior to, during, and after surgical procedures. One study found that 91% of the instruments to be visually clean; however, when examined microscopically, 84% of the instruments had residual debris. While we may not visually observe debris on ophthalmic instruments, when an instrument is introduced to a patient’s eye, we can surmise that some form of debris exists.2

Due to the delicate nature of ophthalmic instruments, it is especially important that we follow the AAMI ST79 guidelines and incorporate lighted magnification to inspect for any hidden bioburden or damages. An experienced instrument repair technician should also inspect ophthalmic instruments under a microscope to rule out any hairline fractures or weak points.

Five years ago, the TASS Task Force performed an analysis of TASS cases, which included 130 questionnaires collected over six years and a review of 71 sites. The results concluded that surgical instrument cleaning and sterilization to be “…by far the most common cause of TASS.” More importantly, they uncovered that “Whenever a TASS outbreak did occur, improved surgical instrument cleaning and adherence to strict cleaning protocols lead to the elimination of further cases of TASS.”3

Precleaning/point-of-use cleaning
All surgical instruments should be precleaned and maintained during and immediately following a procedure. One ophthalmic instrument IFU reads, following the surgical procedure, “Keep used instruments submerged in a basin filled with sterile water until further cleaning is possible. Rinse all instruments with sterile water, including those that were not used.” Effective September 1, 2018, The Joint Commission made it a requirement to perform point-of-use cleaning; otherwise, the risk of a citation may occur.4

Manual cleaning and rinsing
Manual cleaning and the complete rinsing of all surgical instruments is critical. If a detergent is recommended in the ophthalmic instrument IFU, it should be strictly followed and ensure no residue remains to avoid the potential of contaminants introduced into an eye of another patient.

One ophthalmic instrument IFU states, “If you choose to use a cleaning solution be sure it is one recommended for surgical instruments.” Further into the instructions, they direct the user to refer to the joint release from the “ASCRS, AAO, and OOSS Recommendation Regarding Use of Enzyme Detergent for Cleaning Intraocular Surgical Instruments.”5

Facilities may view “if you choose” as confusing and open for interpretation. Users may question whether to use a detergent and if so, what type, pH, etc. 

The TASS Task Force found that enzymes and detergents used during the cleaning of ophthalmic instruments were an important factor in the etiology of TASS. In an article titled “Improve Patient Safety and Eliminate a Risk Factor for TASS,” studies have shown that while following the manufacturers IFUs, “…even the slightest enzyme residue can cause TASS,” and another study suggested that enzyme residues may persist despite proper rinsing. During the FDA meeting, all agreed that the “…potential for enzymatic detergent residue is problematic.” The article mentions that although manufacturer IFUs commonly require routine use of enzymatic detergent and have caused facilities to be cited if they are not using enzymatic detergent, they had recognized that enzymatic detergent cleaning may be necessary in some instances.6

Facilities may view this language as confusing and open for interpretation. Users may ask what constitutes some instances?

An investigation was performed to understand whether enzymatic detergents used in cleaning ophthalmic surgical instruments can cause TASS-like responses. The detergents caused a severe, yet unusual response from the iris when injected intracamerally into rabbit eyes. This response has not been reported in humans with TASS. The time course of inflammation was faster and resolved more quickly than TASS. Simulated cleaning and extraction studies indicate that the level of residual detergent to which a patient could be exposed is significantly less than the lowest dose used in this study. Because that low dose caused no significant observations other than injection of the iris vessels, these results do not support residual enzymatic detergents on surgical instruments as a cause for TASS.7

Rightly so, we must appreciate that the eye is an extremely sensitive organ and any potential breaks or elimination in techniques or protocols may result with a negative effect in a patient’s eye. We must ask if the actual enzymatic detergents are a concern? Should we understand if we are using the proper detergent, concentration, and properly and thoroughly rinsing according to the instrument and detergent manufacturer IFU each and every time, as we do with surgical instrument protocols and guidelines? AAMI ST79 Section 7.6.1 states, “Effective sterilization depends on minimizing the contamination, including detergent and water residues present on items before the sterilization cycle, and thorough cleaning procedures are essential during presterilization processing.”8


  1. https://www.sciencedirect.com/science/article/pii/S0161642012003594
  2. https://www.cdc.gov/infectioncontrol/guidelines/disinfection/sterilization/sterilizing-practices.html
  3. https://www.aao.org/current-insight/ascrs-fda-update-on-tass
  4. https://www.jointcommission.org/issues/article.aspx?Article=G%2fxUdh%2fVKujxJ12FY7q2i0ousSBZsyucrGSdk%2bHj1O8%3d
  5. http://ascrs.org/node/23214
  6. http://www.ascrs.org/sites/default/files/EWAugust2016EnzymeArticle.pdf
  7. https://www.sciencedirect.com/science/article/pii/S0161642012003594
  8. AAMI ST79

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: http://www.asorn.org/client_data/files/2012/114_tassarticle_withascrs2006.pdf

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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