Contaminated trypan blue solution linked to fungal endophthalmitis outbreak after cataract surgery

A retrospective case series published in JAMA Ophthalmology documents an outbreak of postoperative fungal endophthalmitis in 6 patients who underwent cataract surgery in Japan, with microbiological evidence implicating the off-label use of contaminated trypan blue solution as the causative source.¹ The findings carry immediate implications for surgical teams that prepare or dispense trypan blue from non-pharmaceutical, laboratory-grade reagents, a practice that remains widespread in Japan and may occur in other regions where commercially approved ophthalmic formulations are unavailable.

The report, from investigators at Kyorin University School of Medicine in Tokyo, details how a single lot of trypan blue solution was traced back to the same manufacturer across both referring clinics, and how a rare filamentous fungus, was recovered not only from patient aqueous humor and vitreous samples but also from unopened original vials of the solution, suggesting contamination at the point of manufacture rather than during in-clinic preparation.¹

Study overview

This is a single-center, retrospective case series from 6 patients referred to Kyorin Eye Center following cataract surgery at 2 outpatient clinics (clinic A and clinic B) in Japan during 2025. All patients underwent 25-gauge pars plana vitrectomy at the referral center. The primary objectives were to characterize the clinical presentation, microbiological profile, treatment course, and visual outcomes of postoperative fungal endophthalmitis associated with trypan blue use, and to investigate the source of contamination through culture testing of the dye solution.¹

Key findings

Patient ages ranged from 41 to 84 years (mean, 72.7 years), and 5 of 6 patients (83%) were female. None had severe immunocompromising conditions. The mean interval from initial cataract surgery to presentation at the referral center was 16 days. Mean preoperative best-corrected visual acuity (BCVA) at the time of vitrectomy referral was 1.77 logMAR (Snellen equivalent, approximately 20/120).¹

S kiliense was identified in the aqueous humor of 5 eyes and the vitreous of 5 eyes. All 6 eyes underwent vitrectomy, with anterior chamber irrigation around the intraocular lens followed by intravitreal antibiotic injection. Five eyes received intravitreal voriconazole (50 µg/0.1 mL), and all 6 eyes were treated with topical voriconazole (1%). Systemic therapy included intravenous liposomal amphotericin B or oral voriconazole. Two eyes required reoperation for persistent vitreous opacities, and 1 eye necessitated intraocular lens (IOL) extraction.¹

Despite the severity of infection, vitreous opacities and intraocular inflammation resolved in all 6 cases. Mean postoperative BCVA improved substantially to 0.26 logMAR (Snellen equivalent, 20/30).¹

Microbiological investigation revealed S kiliense in cultures from dispensed trypan blue aliquots used in clinic B, as well as in the original trypan blue bottle from that clinic—including an unopened vial. Growth was also detected in multiple other bacterial isolates from the same source. Crucially, when the dispensed solution from clinic B was refiltered through a 0.22-µm membrane before culture submission, no organisms were recovered, suggesting the fungal burden in the original solution exceeded the sterilizing capacity of standard single-pass filtration.¹

Clinical context

Postoperative endophthalmitis after cataract surgery is a low-incidence but vision-threatening complication, with reported rates generally ranging from less than .05% to approximately .3% depending on surgical setting and prophylaxis practices.² The causative organisms are predominantly gram-positive cocci in acute-onset cases, while late-onset disease is most often attributable to Propionibacterium acnes. Fungal endophthalmitis after cataract surgery is distinctly uncommon; commonly implicated species include Candida albicans, Aspergillus species, and Fusarium species.²

Trypan blue has been employed since the late 1990s as an anterior capsule stain to aid capsulorhexis in mature or dense cataracts, where poor intraoperative visualization poses a technical challenge.³ Although commercially approved ophthalmic formulations exist in the United States and Europe, trypan blue lacks pharmaceutical approval in Japan and is typically prepared off-label from laboratory-grade reagents via filter sterilization before surgical use—a practice flagged by the Japanese Ophthalmological Society in 2025 following earlier reports of S kiliense-associated cases at other institutions.¹

Prior outbreaks of postoperative endophthalmitis linked to contaminated trypan blue have been reported, including a 2005 US case series involving a compounding pharmacy and a subsequent cluster of gram-negative bacterial endophthalmitis attributed to contaminated ophthalmic solution.⁴ The current series is notable in that contamination appears to have originated in the manufacturer's stock solution itself, rather than during downstream preparation.

Interpretation

The clinical trajectory of this outbreak differed from the typical presentation of bacterial postoperative endophthalmitis. Vitreous opacities were confined predominantly to the anterior vitreous in most cases, and anterior chamber inflammation, while present, was relatively mild, with hypopyon observed in only 1 of 6 eyes. The authors propose that trypan blue injected into the anterior chamber may traverse zonular gaps and deposit in the anterior vitreous during surgery, where residual contaminated solution may serve as a nidus for fungal proliferation after the anterior chamber has been irrigated and cleared.¹ Contacted for comment, Makoto Inoue, MD, PhD, Professor of Ophthalmology at Kyorin Eye Center, Kyorin University Hospital, Tokyo, Japan, and a co-author of the study, told Ophthalmology Times that given concerns about trypan blue's potential teratogenicity, the dye should be cleared from the eye as soon as possible: "If the lens capsule becomes visible and capsulotomy is performed, it should be removed promptly. A method involving the mixing of trypan blue with a high-molecular-weight viscoelastic substance has already been reported, and it is a method that we use at our hospital as well."

The finding of S kiliense in an unopened manufacturer vial, combined with the successful sterilization achieved by a second filtration pass, indicates that the original reagent harbored a fungal burden beyond what a single .22-µm filter could reliably eliminate. This has practical implications: off-label preparations relying on single-step filtration of laboratory reagents may not consistently achieve sterility, particularly when source material is heavily contaminated. Surgeons at the reporting institution who used a separately sourced, pre-labeled sterile formulation (Gibco Trypan Blue Solution, Thermo Fisher) did not experience any infections, lending further support to this interpretation.¹

The investigators also underscore the potential role of IOL and capsular bag removal in refractory cases of filamentous fungal endophthalmitis, as demonstrated in 1 patient in this series and consistent with prior reports of Fusarium endophthalmitis following cataract surgery.²

Limitations

Several methodological limitations warrant consideration. This was a single-center, retrospective case series involving only 6 patients, precluding statistical analysis. The follow-up period was relatively short, and long-term visual outcomes were not reported. The absence of microbiological cultures from clinic A's trypan blue supply limits definitive attribution of the source across both referring centers. A multicenter study with a larger case population would be necessary to validate these findings and better characterize the risk profile of off-label trypan blue use.¹

Future research

The authors call for prospective, multicenter investigation to establish the prevalence and incidence of trypan blue-associated endophthalmitis in settings where off-label preparations are routinely used. Inoue noted that no multicenter effort is currently in the works: "To the best of my knowledge, there are currently no plans for a multicenter collaborative study in Japan." In the interim, he said, "it is necessary to conduct regular sterility testing at each facility in accordance with their respective microbiological testing protocols," adding that the current study is "meaningful in raising awareness of the risks involved when using non-pharmaceutical preparations for off-label purposes."

Additional work is needed to define optimal antifungal dosing regimens for S kiliense, given the apparent limited efficacy of single-dose intravitreal voriconazole in some patients in this series. The role of high-molecular-weight viscoelastics in preventing trypan blue entry into the vitreous cavity also merits evaluation. From a regulatory standpoint, the findings reinforce calls for formal pharmaceutical approval of ophthalmic trypan blue formulations in markets where it remains unapproved.¹

Inoue offered a measured view on the regulatory question. "While the Japanese Ophthalmological Society recommends the use of pharmaceutical-grade formulations, it has not made their use mandatory," he said. "Of course, it would be ideal to completely suspend off-label use until domestically approved products become available; however, since it is entirely unclear when such products will be approved, we believe it is essential to take steps to ensure that medical care is not delayed for patients who need ophthalmological treatments."

References

1. Torikai T, Shimasaki T, Keino H, et al. Trypan blue use during cataract surgery and postoperative fungal endophthalmitis. JAMA Ophthalmol. Published online May 21, 2026. doi:10.1001/jamaophthalmol.2026.1471

2. Kim SW, Kim JH, Choi M, et al; Korean Retina Society Members. An outbreak of fungal endophthalmitis after cataract surgery in South Korea. JAMA Ophthalmol. 2023;141(3):226-233. doi:10.1001/jamaophthalmol.2022.5927

3. Melles GR, de Waard PW, Pameyer JH, Houdijn Beekhuis W. Trypan blue capsule staining to visualize the capsulorhexis in cataract surgery. J Cataract Refract Surg. 1999;25(1):7-9. doi:10.1016/S0886-3350(99)80004-2

4. Sunenshine R, Schultz M, Lawrence MG, et al. An outbreak of postoperative gram-negative bacterial endophthalmitis associated with contaminated trypan blue ophthalmic solution. Clin Infect Dis. 2009;48(11):1580-1583. doi:10.1086/598938

5. Low L, Shah V, Norridge CFE, Donachie PHJ, Buchan JC. Royal College of Ophthalmologists' National Ophthalmology Database, report 10: risk factors for post-cataract surgery endophthalmitis. Ophthalmology. 2023;130(11):1228-1230. doi:10.1016/j.ophtha.2023.07.021