Several factors involved in TASS, preliminary report states

FAIRFAX, Va. — More than 100 centers have now reported cases of toxic anterior segment syndrome from February through May 2006, according to the American Society of Cataract and Refractive Surgery.

While a single cause or point source related to the most recent outbreaks has not yet been identified, “there have been several potential etiologic factors which have arisen from review of the data,” ASCRS said in a news release.

Preoperative use of nonsteroidal anti-inflammatory drugs may be a potential factor in several of the cases, according to the report. Intracameral anesthetics are also a potential factor, “especially given the short ultrasound time in the majority of cases,” ASCRS said.

ASCRS said a “potential problem” may be the addition of epinephrine to balanced salt solution, as the epinephrine “must be truly preservative free.” Stabilizing agents, such as bisulphites, are not considered preservative free, the report stated.

Reusable cannulas may allow a residue of ophthalmic viscosurgical devices, cortex or other materials that can be toxic when injected into the anterior chamber, ASCRS added.

According to the report, Alcon had manufactured “a majority” of the IOLs reported. However, the statement indicated that the company’s large market share of IOLs may explain the “larger than expected” relationship of one IOL to the reported cases of toxic anterior segment syndrome (TASS). Additionally, the report states that “there may be an issue involved regarding the cleaning of the reusable inserter which is used with a disposable cartridge to place the lens.”

Other issues that ASCRS identified: short surgical turnaround time may affect the sterility of surgical instruments, reusable I&A handpieces could be a potential source of TASS and instrument cleaning could be related if the cleaning materials are not thoroughly flushed from the instruments.

“Follow up of 53 of the 114 centers that have reported cases of TASS directly to a single manufacturer has shown that 41 of the centers have not had any further cases as of the first week of June 2006,” ASCRS said. An additional 12 centers have had more cases since their initial reports in April, however.

TASS incidents should be reported to Nick Mamalis, MD, at nick.mamalis@hsc.utah.edu.