No fee shall be charged for any sport fishing license issued under this chapter to any blind person, and such license shall be a lifetime license not subject to the expiration provisions of section 26-35. Proof of such blindness shall be furnished, in the case of a veteran, by the United States Veterans’ Administration and, in the case of any other person, by the State Board of Education of the Blind. For the purpose of this section, a person shall be blind only if his central visual acuity does not exceed 20/200 in the better eye with correcting lenses, or if his visual acuity is greater than 20/200 but is accompanied by a limitation in the fields of vision such that the widest diameter of the visual field subtends an angle no greater than twenty degrees.