A Case of Birdshot Chorioretinopathy following Varicella Zoster Virus-Induced Progressive Retinal Necrosis in the Contralateral Eye

Birdshot chorioretinopathy is an immune-mediated ocular inflammatory disease of the retina. We report a case of birdshot chorioretinopathy in one eye following progressive retinal necrosis caused by varicella zoster virus (VZV) in the contralateral eye. A 79-year-old female patient complained of decreased vision due to anterior chamber inflammation and vitreous opacity in the left eye starting 10 days earlier. Acute retinal necrosis was suspected and polymerase chain reaction analysis was performed using the anterior chamber aqueous. VZV DNA was detected, and antiviral drugs and steroids were systemically administered together with local therapy. As retinal necrotic changes and retinal detachment gradually developed, vitrectomy and silicone oil tamponade were performed. Despite these procedures, retinal necrosis gradually progressed. Eventually, extensive retinochoroidal atrophy resembling progressive outer retinal necrosis was observed. Two years and 4 months after onset, anterior chamber inflammation and white spots of the retina started to appear in the right eye. The number of white spots gradually increased all around the retina, regardless of systemic treatment with acyclovir and prednisolone. The fundus findings seemed consistent with birdshot chorioretinopathy. Diseases exhibiting white dots in the retina, such as sarcoidosis, were excluded. Ss-OCT examination revealed destruction of the layer structure mainly in the outer layers of the retina and a section of a white dot revealed that the retina appeared to be pulled into the RPE. To the best of our knowledge, this is the first report of birdshot chorioretinopathy in one eye after the onset of VZV-induced retinal necrosis in the contralateral eye.