Dr. Donald H. Gilden responds:

Because shingles is an infectious condition caused by reactivation of varicella zoster virus (VZV), lightheadedness and generalized weakness might occur as with any viral infection.

Another less likely possibility is that the visual symptoms are secondary to VZV retinal necrosis, which is a viral infection of the retina. The combination of lightheadedness, weakness, and visual symptoms might indicate a transient ischemic attack secondary to a VZV vasculopathy, which is a viral infection of the cerebral arteries. New medications also may be a contributing factor. You should be referred promptly to a neurologist for further evaluation.