Linear pattern of West Nile virus-associated chorioretinitis is related to retinal nerve fibres organization

PURPOSE: To clarify the reason for the linear pattern of West Nile virus (WNV)-associated chorioretinitis. METHODS: The study included 12 patients (24 eyes) with WNV-associated chorioretinitis. All the patients underwent a complete ophthalmic evaluation, including dilated fundus examination, fundus photography, fluorescein angiography, and indocyanine green angiography. Characteristics of linear streaks, particularly their relationship to the course of retinal and choroidal vessels, and pattern of retinal nerve fibres, were analysed. RESULTS: All patients had bilateral multifocal chorioretinitis with linear clustering of chorioretinal lesions associated with a variable number of scattered lesions. Linear streaks, variable in number and length, originated from the optic disc or its vicinity in most cases. Their course in all cases appeared to closely follow the course of retinal nerve fibres, rather than that of retinal or choroidal vessels. CONCLUSIONS: Results of our study show that the linear pattern of WNV-associated chorioretinitis is related to retinal nerve fibres organization, suggesting a contiguous spread of WNV virus from central nerve system via the optic nerve fibres to the outer retina, retinal pigment epithelium, and choroid.