1 You have signs of infection, such as: 2  Increased pain, swelling, warmth, or redness around the bite. 3  Red streaks leading from the bite. 4  Pus draining from the bite.  A fever.
A negative index of refraction due to three-dimensional chirality is demonstrated for abilayered metamaterial based on pairs of mutually twisted planar metal patterns in parallel planes, which alsoshows negative electric and magnetic responses and exceptionally strong optical activity and circular dichro-ism.
If your uncorrected vision (without glasses or contact lenses) is normal, then the refractive error is zero (plano) and your vision should be 20/20. A value of 20/20 is normal vision. This means you can read 3/8-inch letters at 20 feet. A small type size is also used to determine normal near vision.