Ortho-keratology or Ortho-K is the usage of a specially designed gas permeable contact lens. It is a lens that gently reshapes the cornea or the front surface of the eyeball to reduce or control myopia. Myopia is referred as Shortsightedness or “Rabun jauh”. Some people refer to it as Hard Lens or OK lenses. You wear these lens overnight and you can see clearly when you wake up. After you remove them of course.