This is likely the largest series of consecutive toxic anterior segment syndrome (TASS) cases from a single institution, as well as the first to report long-term outcomes. They found that TASS was uncommon but not rare. Patients responded well to intensive topical anti-inflammatory medication and usually achieved a good visual outcome. Additionally, this study identifies common late complications from TASS.
It was a retrospective analysis that evaluated all cases of post-cataract surgery TASS occurring at the Aravind Eye Hospital in India during a one-year period. Of 26, 000 consecutive surgeries, they found 60 cases for an incidence of 0.22 percent. About half presented as part of two separate clusters. The remaining cases appeared sporadically with no identifiable etiology. About half had moderate TASS and half had severe TASS with hypopyon.
Despite this severity profile, most patients had excellent long-term visual outcomes All 60 eyes had a minimum postoperative follow-up of one month, at which point the mean CDVA was 0.08 ± 0.06 logMAR (range 0.00 to 0.3 logMAR). This improvement over the preoperative mean visual acuity was statistically significant (P<0.001). Two eyes had a CDVA of 0.30 logMAR attributable to early secondarymembrane formation; the membrane appeared to be a sheet of organized fibrin behind the IOL. The remaining 58 eyes had a CDVA of 0.10 logMAR (6/9Snellen) or better. All eyes had significant visual improvement, and none had worse CDVA than preoperatively.
The mean duration to resolution of severe iridocyclitis was 6.11 days. Of the 24 eyes with a follow-up of at least six months (mean, 11.24 months), anterior capsule contraction and PCO were the principal delayed-onset complications. Six had atrophic iris changes, one had cystoid macular edema, three developed anterior capsule phimosis, and four had posterior capsule opacification (PCO).
All eyes with PCO and capsule phimosis were successfully treated at the six-month follow-up with an Nd:YAG laser capsulotomy and had a mean final CDVA of 0.11 logMAR.
Previous studies of TASS outbreaks often identified a cause. Because of reporting bias, the literature may over-represent the frequency and severity of severe long-term complications. As a result, the lower incidence of serious long-term complications found in this study may be more representative of the spectrum of TASS in the general surgical population compared with a referral practice.
The authors also note that the similarity in complications and visual outcomes at one month and six months suggests that significant late or delayed onset complications, such as corneal endothelial decompensation or secondary glaucoma, are uncommon in eyes that recover good vision by one month postoperatively.
While this study found relatively good outcomes, it should not diminish the fact that some cases of TASS can have devastating ocular consequences. Surgical facilities must continue to vigorously adhere to cleaning and sterilization protocols.