Intravitreal Foscarnet Therapy for Acyclovir-Resistant Acute Retinal Necrosis After Herpes Simplex Encephalitis

The development of acute retinal necrosis (ARN) is not uncommon among individuals with a history of herpes simplex encephalitis, as the virus may be capable of transport via axonal cells to the neuroretina. Though it is known that ARN severely threatens vision, timely initiation of effective therapy can help save a patient's vision and retina. In this case report, clinical resistance to acyclovir was found. Subsequent treatment with intravitreal foscarnet resulted in immediate clinical improvement. This case suggests that patients with acute retinal necrosis can be considered for treatment with intravitreal foscarnet in the setting of systemic acyclovir resistance.