Preventing Infection After Cataract Surgery

Efficacy of Intracameral Moxifloxacin in Prevention of Postcataract Surgery Endophthalmitis: Randomized Control Trial

Sharma N, Sen A, Sharma M, et al¹
Industry sponsorship for this study: None

ABSTRACT SUMMARY

This prospective randomized controlled trial (RCT) of 60,000 patients compared the incidence of postoperative endophthalmitis (POE) in a control group that received only pre- and postoperative topical antibiotics to that of a treatment group that also received 500 µg (0.1 mL of a 0.5% solution) of intracameral (IC) moxifloxacin at the end of cataract surgery. 

Between 2018 and 2024, the patients were randomly assigned 1:1 to receive either IC moxifloxacin prophylaxis (ICMP) or no IC antibiotic; they were not informed of their group assignment. All patients received the same regimen of pre- and postoperative topical moxifloxacin drops, and all of them underwent phaco cataract surgery, performed by one of eight surgeons. The study excluded combined surgeries, procedures performed by trainees, patients with open globe injuries, and patients younger than 40 years of age. The two groups were statistically similar. 

The odds of developing POE were two and a half times lower in the ICMP group; 0.02% and 0.05% of the ICMP and control eyes, respectively, developed POE (P = .04). The posterior capsule ruptured in approximately 1.5% of eyes in each group, but the rate of POE was seven times higher in eyes that experienced this complication. Among eyes that developed POE, the incidence of posterior capsular rupture was 50% and 38% in the ICMP and control groups, respectively. 

DISCUSSION

The landmark 2007 ESCRS RCT was the first major study of the use of IC antibiotics—specifically cefuroxime—for infection prophylaxis after cataract surgery.² That study divided patients into four equal treatment groups: (1) IC + topical antibiotics, (2) IC antibiotics only, (3) topical antibiotics only, and (4) control (no antibiotic prophylaxis). The trial was halted early after 16,000 patients had been treated because an almost fivefold reduction in POE rates was observed in the IC + topical group (0.07% vs 0.34% in the control group). It was deemed unethical to withhold IC cefuroxime from half the patients. The 2007 ESCRS RCT also indicated that sutureless clear corneal incisions, as constructed at the time, and silicone IOLs might increase the rate of POE, but those were not prespecified trial endpoints. Several smaller trials and retrospective studies subsequently confirmed the protective effect of IC cefuroxime. 

A major limitation of the 2007 ESCRS RCT was the need to obtain an intravenous formulation of cefuroxime and then dilute and buffer it appropriately for intraocular use. This obstacle was addressed in 2012 when a commercial formulation of cefuroxime for ophthalmic use was approved in Europe.

Because cefuroxime is not globally available in an ophthalmic formulation, preservative-free topical moxifloxacin 0.5% was adopted for IC use, initially in India around 2011. A large retrospective study conducted at the Aravind Eye Hospital system in India was published in 2017.³ In more than 600,000 cases, the incidence of POE decreased by a factor of 3.5 (from 0.07% to 0.02%) after IC moxifloxacin was introduced. A 2019 update of that study included more than 2 million cataract operations, both phacoemulsification and manual small-incision cataract surgery, performed between 2011 and 2018.⁴ The updated results supported the initial study findings; the incidence of POE was reduced by a factor of 3.5 overall, and there was a statistically significant decrease in the rate of occurrence for the eyes that underwent phacoemulsification alone, the eyes that received manual small-incision cataract surgery alone, and those from either group in which the posterior capsule ruptured during surgery. 

The huge amount of data notwithstanding, the main limitation of these earlier studies of IC moxifloxacin was their retrospective design. The more recent cases received ICMP but might also have benefited from improved surgical techniques, such as smaller incisions and preloaded IOLs. The current study by Sharma et al¹ addressed that uncertainty by confirming a highly significant reduction in POE risk with the use of ICMP. This study did not, however, evaluate the performance of ICMP alone without perioperative topical antibiotics.

Neither Sharma et al¹ nor other published trials of ICMP discussed the narrow therapeutic window or the potential for corneal toxicity or toxic anterior segment syndrome (TASS) if an incorrect formulation or concentration of moxifloxacin is used. A 2023 ASCRS clinical advisory on ICMP after cataract surgery⁵ noted that two concentrations of preservative-free moxifloxacin are available in the United States: 0.5% (5 mg/mL, the same as the commercial preparation) and 0.1% (1 mg/mL). The current study¹ and most others published to date have used 0.1 mL of the 0.5% solution for a total dose of 500 µg, a concentration that has been shown to be safe and effective. Some published evidence has indicated that 0.1 mL of the 0.1% solution (100 µg) might be inadequate,⁵ so the ASCRS clinical advisory committee recommended using 0.5 mL of the lower concentration to achieve the same total dose of 500 µg. There have, however, been documented cases of corneal endothelial toxicity when 0.5 mL of the 0.5% solution was used (total dose of 2,500 µg).⁶ It is therefore critical that surgeons know what concentration of moxifloxacin is being used and adjust dosing accordingly. Also, any commercial preparation of topical moxifloxacin that may contain an additive (such as xanthan gum) should not be used intracamerally due to a high risk of TASS.⁵

As more jurisdictions and individual surgeons begin offering immediately sequential bilateral cataract surgery, minimizing the risk of POE and the incidence of other sight-threatening complications such as TASS becomes increasingly important.

The study by Sharma et al¹ serves as a cautionary reminder to surgeons that, although POE is rare and usually responds well to treatment, it can have devastating consequences. In this RCT, the rate of phthisis after POE was 18% despite timely and aggressive treatment.

Incidence of Toxic Anterior Segment Syndrome and Endophthalmitis in 190 000 Eyes in a High-Volume, Multisurgeon, National Network of Ambulatory Surgical Centers Using Uniform Perioperative Protocols

Wallerstein A, Lekhi V, Ahmed IK, et al⁷
Industry sponsorship of this study: None

ABSTRACT SUMMARY

This retrospective analysis of the incidence of TASS and endophthalmitis over a 3-year period (from 2022 to 2025) included more than 190,000 cases of cataract surgery or refractive lens exchange in a Canadian network of 54 commercial outpatient ambulatory surgical centers. About 60% of the procedures were performed as immediately sequential bilateral surgery (ISBS), and approximately 40% were performed as either delayed sequential bilateral surgery or unilateral surgery. Standardized perioperative protocols were followed, including all current ASCRS TASS Task Force recommendations. Separate instrument sets, separate lot numbers of IC medications, and individual surgical preparation and draping were used for each eye in ISBS cases. Phacoemulsification was performed through sutureless clear corneal incisions in all cases. A standardized mandatory reporting structure was used, with individual surgeon follow-up to ensure compliance. In total, there were 10 TASS cases (incidence of 5.3/100,000 or 0.0053%), and all were managed successfully with topical steroids. This incidence was significantly lower than has been reported in the peer-reviewed literature (0.023%–0.22%).⁸ One TASS case was bilateral, but whether it occurred in an ISBS patient was not stated.

All patients received topical moxifloxacin infection prophylaxis, and 73% received IC moxifloxacin as well. There were three cases of POE, and none was bilateral (overall incidence rate, 1.6/100,000 or 0.0016%). The numbers were too small to detect a meaningful difference between ICMP and non-ICMP. The incidence of POE was much lower than the average reported in the peer-reviewed literature (0.07%).⁸

DISCUSSION

The study by Wallerstein and colleagues is noteworthy because it reported the lowest rates of both TASS and POE in the literature to date. For comparison, a forthcoming IRIS (Intelligent Research in Sight) Registry analysis found the current POE rate in a large cross-section of US adults after cataract surgery to be 0.038%, a respectably low number.⁹ The study by Wallerstein et al yielded a POE rate that was more than 20 times lower.⁷ It was not stated how many patients had a ruptured posterior capsule, so it is impossible to determine the effect of this established risk factor on the low rate of POE observed. It was not specified whether any of the IOLs were preloaded. Nor was the rate of any other intraoperative complications stated. 

The study demonstrated that, compared to expected rates, the incidence of TASS and POE could be reduced at least 10-fold through rigorous adherence to current established best practices for preventing infection and TASS during cataract and refractive lens exchange surgery in a real-world, diverse, ambulatory surgical center setting.