How high is the refractive error in a contact?

Ref error. No limits as long as the health of the eye is fine. There are also specialty contact lenses for unusual cases.

Related Questions

How high or low is the refractive error in a contact lens?

Depends on the brand. On average, can range from minus 20 to plus 10 in quarter or half diopter steps. Depends on soft vs. Hard contact lens, astigmatism correction, etc. Plus custom lenses can be made. Read more...
For almost all. Contact lenses are available to correct almost every refractive error, including various levels of myopia, hyperopia, and astigmatism. Read more...