Herpes simplex virus type 1 replicates in the lens and induces cataracts in mice

In a mouse model, cataracts were produced after corneal inoculation with herpes simplex virus type 1 (HSV-1) strain F. Viral antigen was detected in vivo by the immunoperoxidase technique in lens fibers and occasionally in lens epithelial cell nuclei at 4 and 5 days postinoculation. HSV-1 replication within the lens was further demonstrated by virus isolation from lenses that had been inoculated in vitro. Lens lesions in mice were present as early as 4 days postinoculation and by later times (23 to 60 days postinoculation), severe degenerative changes typical of cataracts were present in many of the lenses examined histologically. Viral DNA was detected in extracts of lenses from infected animals at 5 and 11 days postinoculation. In contrast to HSV-1 F, the KOS strain of HSV-1 produced intraocular infection and cataracts at a much lower frequency in mice. Lens lesions appear to be induced directly by viral replication within the lens; however, other mechanisms involving inflammation in adjacent eye structures may also be involved in the pathogenesis of these lesions. Based upon these data, it is reasonable to consider the possibility that HSV-1 may be involved in the production of cataracts in humans in some cases.