Real-world data on toxic anterior segment syndrome

An ounce of prevention is worth a pound of cure. —Benjamin Franklin Toxic anterior segment syndrome (TASS) is defined as a sterile postoperative inflammatory reaction caused by a noninfectious agent that gains access to the anterior segment.1 The toxic inflammatory process typically starts 12 to 48 hours after anterior segment surgery of any kind, is limited to the anterior segment of the eye, is always Gram stain and culture negative, and usually improves with steroid treatment. The primary differential diagnosis of TASS is infectious endophthalmitis. Studies demonstrate that TASS can be caused by different factors related to solutions used in conjunction with anterior segment surgery (eg, solutions containing preservatives used intraocularly), processing of surgical instruments, and intraocular devices implanted during surgery, among many others.1–5 The bulk of the literature available on TASS is represented by case series describing specific TASS outbreaks, as well as results from questionnaires issued from such outbreaks, which were submitted for analysis of possible causality.2–5 Large-scale, real-world data on TASS remain limited, especially from high-volume ambulatory surgical centers (ASCs). In this issue, a Correspondence by Wallerstein et al. (page 406) describes a retrospective study assessing the incidence of TASS across nonhospital ASCs in Canada. Data included 190 005 consecutive eyes from 109 121 patients. Refractive lens exchange (RLE) and cataract surgery procedures were performed by 172 surgeons across 54 surgical centers from January 2022 to April 2025, including sites contracted to perform publicly funded cataract surgery. TASS reporting followed standardized protocols, which were implemented across all facilities, with data extracted from a centralized electronic medical record and risk management system. A comprehensive survey was also sent to all surgeons requesting confirmation of any TASS case. At the time of the study analysis, 59 275 (54.32%) patients underwent immediate sequential bilateral cataract surgery or RLE, 22 020 (20.18%) had delayed sequential bilateral surgery, and 27 826 (25.50%) had unilateral surgery or were pending the second procedure. In this study, there were 10 confirmed TASS cases, observed in 9 patients (1 bilateral case), for an incidence of 5.3 cases per 100 000 eyes (0.0053%). They included 3 cases in eyes undergoing RLE, as well as 2 private and 5 public cataract cases, which were all managed successfully with intensive topical corticosteroids. The authors attributed the relatively low TASS rate to implementation of sterilization guidelines by the ASCRS, such as elimination of enzymatic detergents, use of distilled water during instrument reprocessing, and standardized autoclaving and maintenance routines.6,7 The aforementioned Correspondence correlates well with a recent study designed to identify trends in the reporting of TASS to the ASCRS TASS Task Force from 2012 to 2022.3 Data from 77 questionnaires (68 from the United States, 5 from Canada, and 1 each from Slovenia, Mexico, Colombia, and Malaysia) were analyzed in this study. The reporting centers performed 56 319 cataract surgeries and reported 539 cases of TASS during this period. Common practices associated with the TASS outbreaks in the surveys included reuse of single-use cannulas, phacoemulsification, and irrigation/aspiration tips; use of enzymatic cleaners; inadequate flushing of phacoemulsification and irrigation/aspiration handpieces; reuse of phacoemulsification tubing; use of preservative-containing intracameral anesthetic; and addition of antibiotics to a balanced salt solution. These data were compared with data from 2007 up to 2012 obtained in a similar manner.4,5 The comparison showed that the frequency of TASS outbreaks has dramatically decreased in the past decade (a 10-fold decrease of cases per year). Real-world data are defined as data relating to patient health status and/or the delivery of health care routinely collected from a variety of sources, such as electronic health records, medical claims, data from product or disease registries, and data gathered from other sources (eg, digital health technologies) that can inform on health status.8 These types of data keep gaining ground as a way to efficiently answer research questions relevant to patients outside of a formal clinical trial setting. It is important to keep in mind though that these are ultimately large-scale retrospective cohort studies, carrying therefore possible inherent limitations, such as lack of control groups, incomplete or absent data points, and selection bias, among others.8,9 However, in the context of an entity such as TASS, which can stem from multiple sources, tapping into significant amounts of existing clinical practice data may be a valuable tool to gain insight into rate trends. It is appropriate to remind readers that help assessing causes of TASS during outbreaks is still available through the ASCRS TASS Task Force. Recommended practices for cleaning and sterilizing intraocular surgical instruments were published in 2007 in this journal, and updated in 2018.6,7 They are also available in the ASCRS website, together with other TASS registry tools: a form for voluntary report to the U.S. Food and Drug Administration, an instrument reprocessing and product questionnaire, and a questionnaire focused on sterilization practices.10 Once completed, the questionnaires are sent to members of the Task Force, led by Nick Mamalis, MD, who will analyze the answers and provide a complete report with recommendations to the submitting center. Although pinpointing the exact cause(s) of TASS may be quite difficult or even not possible in many cases, going through the questionnaires still is an excellent exercise for practices to review and update their overall operating room protocols to current standards. It is noteworthy that the main “treatment” for TASS continues to be centered on prevention because once the toxic agent enters the eye and causes damage, there is little the clinician can do other than suppress the secondary inflammatory response.1 Therefore, promoting awareness of this condition and appropriate measures to prevent its occurrence was demonstrated to be the most important tool in decreasing TASS rates.