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Toxic Anterior Segment Syndrome: Are We Ever out of the Woods? (part 1)
By Sara Freiberg

Recently, a surgeon and a sterile processing manager were discussing turnover time for eye instruments. The sterile processing manager shared the instrument process and protocol that her staff performs once a procedure is complete. She shared the importance of point-of-use cleaning (and mentioned that it begins in the OR), manual cleaning, flushing and rinsing, tray preparation, sterilization, inspection, etc.

Following her communication of these protocols, the surgeon responded that his eye instruments do not contain bioburden. The sterile processing manager paused for a moment and politely responded that all instruments used in surgery contain bioburden. While ophthalmic instruments do not commonly contain blood or visible debris (i.e., blood and tissue), bioburden in the form of viscoelastic solutions can remain on ophthalmic instrumentation and must be removed prior to cleaning and sterilization. She went on to say that their opthalmic instrument manufacturer instructions for use specifically state, “Do not allow medicines, viscoelastic, irrigating solutions (balanced salt solution), or protein residue to dry on instruments.” The doctor walked away.

As healthcare workers, we understand all too well that bioburden on instruments can dry and harden within minutes, creating a biofilm and potentially interfering with the sterilization process. If point-of-use cleaning is not performed in a timely manner and according to the regulatory and manufacturer guidelines, we risk patient safety.

This conversation led me to write on toxic anterior segment syndrome (TASS). TASS is a devastating outcome for the patient that is commonly recognized within 12–48 hours following cataract or anterior segment surgery. Patients are seen with inflammation, redness, blurred vision, a severe sensitivity to light, and corneal edema that spans limbus to limbus. When a noninfectious substance enters the anterior segment of a patient’s eye, it presents itself as an acute postoperativeinflammatory reaction and brings toxic damage to the patient’s intraocular tissues. If not caught and treated in a timely manner, TASS can cause atrophy of the iris, optic nerve damage, posterior capsular opacification, cystoid macular edema, and other serious conditions. In some cases, patients must undergo an additional surgical procedure.1

In 2006, there were numerous outbreaks of patients who developed toxic anterior segment syndrome following cataract surgery. It was such a concern that the FDA became involved and developed a TASS Task Force. The American Society of Cataract and Refractive Surgery (ASCRS) TASS Task Force is comprised of physicians, nurses, infection preventionists, ophthalmologists, members of industry, the U.S. Food and Drug Administration (FDA), and the Centers for Disease Control and Prevention (CDC).

As healthcare workers, we learned some important things during that initial outbreak, and we modified some practices prior to, during, and following cataract procedures. Although we have seen no major outbreaks of TASS since 2006, it is important to note that hundreds of TASS adverse reports have been submitted to the FDA’s Maude Adverse Event Database. We must understand that contributing factors that can cause TASS are still a concern.Finding the cause of the problem can be a long, nerve-wracking process for facilities and the source must be identified in a timely manner, otherwise TASS can recur.

What are some potential contributors of TASS?
Balanced salt solution (BSS) is an important solution used during cataract surgery to irrigate and hydrate the eye tissue and maintain the natural condition of the eye while the surgeon is performing the intricate steps of a cataract removal. If the BSS contains any type of endotoxins, it has the potential to cause TASS.

When the initial outbreak of TASS occurred in 2006, it was found that many lots of contaminated BSS were used and, according to the FDA, contained dangerous levels of endotoxin responsible for the outbreak, which led to the FDA issuing a recall withdrawal of this particular brand of BSS. In 2008, there was another recall of BSS and tests of this lot had revealed elevated levels of endotoxin where 66 adverse events were reported with patients showing signs of TASS.Studies have shown that 0.08 endotoxin units (EU) in a BSS can elicit inflammation in the eye. In 2015, the FDA issued a Guidance for Industry: Endotoxin Testing Recommendations for Single-Use Intraocular Ophthalmic Devices“ in an effort to mitigate future Toxic Anterior Segment Syndrome (TASS) outbreaks.”4

In addition, any abnormalities in the BSS, such as incorrect pH levels or medications or antibiotics added to the BSS, may also contribute to TASS. Although a few lots of BSS were among the culprits, it still remains difficult to target the actual cause of TASS. Many other factors play a role that may contribute to TASS infection before, during, and after a cataract procedure.

Ophthalmic viscosurgical devices
Ophthalmic viscosurgical devices (OVDs) were first used in ophthalmic surgery in 1972, with Healon used as the first viscoelastic substance. OVDs are routinely used in cataract surgery to protect the delicate ocular structures, compartmentalize in the eye, pressurize the anterior chamber, and provide a faster and safer surgery with better visual recovery for patients.5

The human eye is composed of some key structures: the cornea, lens, retina, vitreous humor, aqueous humor. Aqueous humor is the clear liquid found in the space between the cornea and the lens and its function entails nourishing and removing wastes of the avascular structures.Vitreous humor, on the other hand, is a clear, gel-like substance located in the rear part of the eye, which includes the space between the lens and the retina. The main function of vitreous humor is to hold the retina in the eye and provide a shape to the eye. Surgeons use OVDs as a replacement for vitreous and aqueous humor.

While OVDs are commonly used during cataract surgery, it is important to note that if a significant amount of viscoelastic is left behind in the anterior segment of the eye, or viscoelastic residual is left remaining in instrument lumens, it has the potential to cause TASS when the material is potentially flushed into the anterior segment of another patient’s eye during subsequent cataract cases.

  1. http://eyeopener.accutome.com/if-only-every-ophthalmologist-knew-this-about-tass/
  2. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/search.cfm
  3. https://www.pharmacy.ca.gov/publications/fda_recall.pdf
  4. https://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM393376.pdf
  5. https://www.reviewofophthalmology.com/article/understanding-and-using-the-full-spectrum-of-ovds
  6. https://www.differencebetween.com/difference-between-aqueous-humor-and-vs-vitreous-humor/

 

 

 

 

 

Bio 

  • 16 years’ experience in the operating room as a CST
  • Clinical specialist for medical device companies
  • Product manager for medical device company
  • Clinical education manager – Integra LifeScience (Jarit Instruments division)
  • Clinical education manager – Northfield Medical
  • AS in surgical technology
  • BA in business/marketing
  • CST, CBSPD, CER certification
  • Voting board member AAMI WG84/ST_91 – flexible endoscopes
  • Member of AAMI, IAHCSMM

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