Endophthalmitis after intravitreal injection with or without triamcinolone - A 10-year investigation in a tertiary hospital.

Purpose: Intravitreal injections (IVIs) have been the most important treatment strategies in retinal diseases. With the increasing use of IVIs, the incidence of endophthalmitis has inevitably risen. Triamcinolone acetonide (TA) used in IVIs has been suspected as a risk factor for post-IVI endophthalmitis. This study investigates the incidence, clinical presentations, and microscopic findings of post-IVI endophthalmitis with or without TA, aiming to provide a better understanding of this issue.

Materials and methods: This retrospective study included patients receiving IVIs at a tertiary referral center from September 2010 to August 2020. Injections were performed under sterile conditions, and endophthalmitis was diagnosed based on acute ocular symptoms within 6 weeks postinjection. Statistical analysis was preformed between endophthalmitis with or without TA.

Results: Out of 18,365 IVIs, the incidence of endophthalmitis was 0.038%. The incidence of TA-associated endophthalmitis (TAAE) (5 in 939 IVIs, 0.532%) was significantly higher (P < 0.0001) than that of non-TAAE (2 in 17,426 IVIs, 0.011%). All five TAAE cases were culture negative, while the two non-TAAE cases were culture positive with Staphylococcus epidermidis (P < 0.0001). The outcomes for TAAE were generally good, with patients returning to their preendophthalmitis vision levels. Risk factors for TAAE included prior IVIs and prior TA injections. Microscopy revealed fern-like crystalline materials in the anterior chamber of one TAAE case.

Conclusion: This study highlights that TA is significantly associated with a higher incidence of post-IVI endophthalmitis, which is also significantly associated with culture-negative results. This implies the possibility of a noninfectious cause in TAAE.