Intravitreal Dexamethasone Implants for Macular Edema Secondary to Acute Retinal Necrosis

PURPOSE: To assess the effectiveness and risk of intravitreal injection of dexamethasone implants in treating macular edema (ME) secondary to acute retinal necrosis (ARN). METHODS: In this retrospective, noncomparative case series study, five patients who developed secondary ME after ARN and received an intravitreal dexamethasone implant injection were enrolled. The features of secondary ME on OCT and the outcomes of dexamethasone intravitreal implanting were presented. RESULTS: The mean age of the patients was 59 years (range, 51-61 years). All patients had unilateral involvement, and all 5 eyes showed mild to moderate anterior uveitis, retinal necrosis, and vasculitis. Herpes zoster virus was detected in all eyes using PCR, and timely antiviral and anti-inflammatory treatment was performed. Aqueous humor samples were negative for herpes zoster virus DNA, and resolution of viral retinitis was noted upon the occurrence of ME. Additionally, three eyes received pars plana vitrectomy with silicone oil prior to ME development. All eyes presented with intraretinal fluid, hyper-reflective foci, and impairments of the external limiting membrane/ellipsoid zone at varying degrees on OCT images. Epiretinal membrane was exhibited in 80% of eyes, but no vitreoretinal traction was detected. Subretinal fluid was visible in 60% of eyes. ME was relieved effectively in all eyes after intravitreal dexamethasone implanting. One of these patients experienced three episodes of ME. No recurrence of retinal necrosis or corticosteroid-associated ocular hypertension was observed during the follow-up period. CONCLUSION: Intravitreal injection of dexamethasone implants can effectively alleviate ME secondary to ARN and improve visual acuity with no adverse reactions.