Intravitreal Foscarnet for the Treatment of Acyclovir-resistant Acute Retinal Necrosis Caused by Varicella Zoster Virus

Purpose: To report of a case of acute retinal necrosis (ARN), successfully treated with intravitreal foscarnet. Methods: Case report. Results: A 40-year-old man diagnosed with varicella zoster virus (VZV)-induced ARN failed standard acyclovir treatment. He was treated subsequently with intravenous foscarnet, but developed acute renal failure after 1 day of treatment. All systemic anti-viral agents were discontinued, and intravitreal foscarnet was administered weekly. After 5 injections, the retinitis was dramatically improved. Conclusions: Intravitreal foscarnet was efficacious in the treatment of acyclovir-resistant ARN caused by VZV. It may be used as the sole treatment in patients with intolerance to systemic administration.