It sounds like this must be very unpleasant and uncomfortable for your friend. In general, the chicken pox virus does not typically cause eye symptoms such as you describe. Adults with a chicken pox infection can be very, very uncomfortable, as the symptoms do tend to be more severe and bothersome in adults than in children, but the more typical presentation is the obvious skin manifestations an then feelings of fatigue and malaise. If your friend is experiencing significant eye concerns particularly with any eye pain or changes of vision, it is best that he see his doctor
right away for an evaluation. Hopefully this will turn out to be nothing more serious than a mild allergic reaction or even a benign viral infection (just because someone has one illness doesn't mean they can't catch another!), but one certainly wouldn't want to miss the rare but more serious conditions that can affect the eyes and potentially cause much more serious problems with vision. If your friend's primary care physician
sees anything particularly worrisome on exam or hears about any "red flag" symptoms, he or she can easily refer your friend to an ophthalmologist
if necessary. Hopefully your friend will feel much better soon!