Toxic anterior segment syndrome (TASS) outbreaks occurring at four cataract surgery centers in Canada launched a comprehensive investigation to identify the possible cause(s). Use of a specific brand of textured surgical gloves (Triumph LT, Medline) was identified as a factor, and new cases of TASS have been avoided since use of that particular product was discontinued.
Chicago-Outcomes from an investigation into outbreaks of toxic anterior segment syndrome (TASS) occurring at several Canadian cataract surgery centers raise the possibility that a specific brand of textured surgical gloves (Triumph LT, Medline) might be a risk factor for TASS, said Simon P. Holland, MD, at the annual meeting of the American Society of Cataract and Refractive Surgery.
"Outbreaks of TASS can be multifactorial and investigations of the etiology are difficult because of their retrospective nature," said Dr. Holland, clinical professor, department of ophthalmology and visual sciences, University of British Columbia, Vancouver, Canada. "In this situation, there is no proof of a cause and effect association and the fact that this particular glove has the highest market share in Canada may be a confounder.
"However, we have a huge responsibility to our patients to try to avoid TASS because of its potentially serious consequences," he said. "Therefore, considering the strength of the association found in our investigation, we suggest that surgeons might be wise to consider textured gloves as a potential cause in the presence of an ongoing TASS outbreak."
A comprehensive investigation into possible causes for TASS was conducted at three of four cataract surgical centers that were experiencing prolonged outbreaks. All aspects of the surgical and sterilization processes were evaluated and multiple changes were introduced.
Interest in the textured gloves as an etiologic factor in the TASS outbreaks arose based on a published report by Hoffman et al. in 2006 linking textured glove use with diffuse lamellar keratitis. At one center, an interesting clue implicating an association between TASS and the textured gloves was the fact that one surgeon with no cases of TASS used a different glove size and folded the IOLs differently from surgeons who were experiencing problems with TASS.
"Based on these features, we thought perhaps this surgeon's patients were protected because the IOL haptics were not being touched with the gloves," he said. "The gloves in use at the clinic were changed and no new cases of TASS occurred. However, when one surgeon later operated using the discontinued brand of gloves in three patients with poor prognosis who had age-related macular degeneration, TASS developed in all three."
At a second center, a major TASS outbreak involving 66 of 1,715 eyes led to a shutdown of all cataract surgery cases for 3 weeks. No obvious causes could be identified, but a total of 32 changes were made in the procedures. The outbreak resolved but another outbreak occurred; by that time the idea of glove involvement had developed.
"This center was using the same textured glove," he said. "During 14 months after switching brands, there have been no cases of TASS."
Dr. Holland reported that his own institution in Vancouver was affected by a prolonged TASS outbreak affecting 14 cases out of 1,674 operations. Use of the textured glove was stopped there as well and this was associated with resolution of the outbreak.
"At our center, the incidence of TASS among surgeons who were using the textured glove was significantly higher than among those who were not," Dr. Holland said.
The factors associated with the textured glove that could account for the risk of TASS are unclear. Scanning electron micrographs of the textured gloves and the smoother gloves show, surprisingly, that there is significant debris on the surface of both.
Alternatively, the presence of silicone oils, which for some gloves are used as lubricants in the manufacturing process and to make the gloves easier to wear, may be an etiologic factor. Evidence supporting that hypothesis derives from Fourier transform infrared spectroscopy analysis comparing the textured glove implicated in the outbreak with the replacement glove showed a difference in silicone peaks.