LASIK is used to treat farsightedness, nearsightedness and astigmatism. However, not everyone with these vision problems will be able to get the surgery. Extremes in cornea shape and thinness often mean an individual will not be a proper candidate for LASIK.
Additionally, certain conditions and medications can be relative or absolute contraindications for the surgery. LASIK is contraindicated for individuals with collagen vascular, autoimmune or immune deficiency diseases; signs of keratoconus or abnormal corneal topography (shape). The same goes for individuals taking Accutane or Amiodarone. LASIK should not be performed on pregnant women or nursing mothers, either.