Outbreak of TASS reported at Toronto cataract surgery unit

Cataract surgeries were temporarily suspended at a Toronto hospital after a cluster of cases of toxic anterior segment syndrome was detected there, hospital officials said.

On November 15, officials at Scarborough Hospital announced that, "as a precautionary measure," all cataract surgeries at the hospital had been temporarily canceled after "a number of its patients" experienced toxic anterior segment syndrome (TASS) after cataract surgery. TASS is a postoperative inflammatory reaction in the anterior chamber without apparent infectious etiology.

News media in Canada variously described the number of patients affected as "more than a dozen," "dozens," and "30 patients." Despite repeated attempts, Ocular Surgery News was unable to confirm the number of patients affected with Scarborough Hospital officials.

The hospital resumed cataract surgeries on November 22 after bringing in an independent research firm to investigate the outbreak, according to hospital press releases. Scarborough Hospital "has reviewed all of its processes and taken steps, which it believes are appropriate in the circumstances to reduce the risk of any patient developing TASS," officials said in announcing the resumption of cataract surgery.

The findings of the independent research firm were not released.

According to Nick Mamalis, MD, the head of the American Society of Cataract Surgery's ad hoc task force on TASS, the single-center outbreak does not rise above the usual "background incidence" of TASS and is not indicative of another North America-wide rise in the incidence of TASS as was seen earlier this year.

"What we've seen is that we're back down to our baseline level. ... This is definitely an outbreak for their facility that is out of the normal for them, but may not be related to any nationwide or North America-wide outbreak," he said.