Mid-term safety and effectiveness of intravitreal dexamethasone implant to treat persistent cystoid macular edema in vitrectomized eyes for bacterial endophthalmitis

Purpose To evaluate the mid-term safety and effectiveness of intravitreal dexamethasone implant (DEX-i) for treating unresponsive to medical therapy cystoid macular edema (CME) in vitrectomized eyes for endophthalmitis. Methods Retrospective and interventional case series study conducted on vitrectomized eyes for endophthalmitis that developed a CME that did not adequately respond to medical therapy, who underwent 0.7-mg DEX-i. Main outcome measures were changes in central retinal thickness (CRT) and best corrected visual acuity (BCVA). Results Eleven eyes were included in the study. Microbiological findings of vitreous biopsies were 7 (63.6%) staphylococcus epidermidis; 3 (27.3%) Pseudomonas aeruginosa ; and 1 (9.1%) Propionibacterium acnes . Median (interquartile range, IqR) duration of CME was 4.0 (3.0–4.0) months. Median (IqR) time between vitrectomy and DEX-i was 9.0 (9.0–11.0) months. Median CRT was significantly decreased from 548.0 (412.8–572.5) µm at baseline to 308.0 (281.3–365.5) µm at month 6 ( p = 0.0009, Friedman test). Median BCVA significantly improved from 38.0 (30.5–44.8) letters at baseline to 50.0 (46.8–53.0) letters at month 6 ( p < 0.0001, Friedman), with 9 (81.8%) eyes gaining ≥ 10 letters. Elevation of intraocular pressure was observed in one (9.1%) eye, which was successfully controlled with medical therapy. No recurrence of endophthalmitis or other complications was observed. Eight (72.7%) eyes required an additional DEX-i, while 3 (27.3%) were successfully controlled with only one DEX-i. CME recurrence occurred in 5 (62.5%) Gram-positive and 3 (100.0%) Gram-negative bacteria ( p = 0.2357). Conclusion In vitrectomized eyes for endophthalmitis affected by CME unresponsive to medical therapy, DEX-i had an acceptable safety profile and achieved favorable outcomes. The possibility of suppressing mechanisms for infection control should be taken into account, although correct management of endophthalmitis and long time without reactivation before DEX-i reduce the risk.