Okla. Admin. Code § 317:35-5-5
An individual is related to the blind if he/she has central visual acuity of 20/200 or less in the better eye with the use of a correcting lens. When the limitation in the fields of vision is such that the widest diameter of the visual field subtends an angle no greater than 20 degrees, central visual acuity is 20/200 or less. If the individual is to be related to the blind, the exact procedures are followed as are outlined for the disabled. Exception: If a decision on blindness is to be made and current medical information regarding degree of vision is not available to the local office, the individual is referred to an ophthalmologist or optometrist, with payment authorized by the local office, for an examination or existing current medical information. Upon receipt, the local office routes the medical information and the Medical Social Summary to the LOCEU where the decision on blindness is made.
Okla. Admin. Code § 317:35-5-5