Okla. Stat. tit. 59, § 59-521: Exceptions

No health care services may be performed under this act in any

of the following areas:

(a) The measurement of the powers or range of human vision, or

the determination of the accommodation and refractive states of the

human eye or the scope of its functions in general, or the fitting

or adaptation of lenses or frames for the aid thereof.

(b) The prescribing or directing the use of, or using, any

optical device in connection with ocular exercises, visual training,

vision training or orthoptics.

(c) The prescribing of contact lenses for, or the fitting or

adaptation of contact lenses to, the human eye.

Nothing in this section shall preclude the performance of

routine visual screening.