No person who is either blind or deaf shall be required to pay the poll tax specified in the Constitution as a prerequisite to voting in Alabama; but, on the contrary, every blind or deaf person shall be exempt from the payment of all poll taxes which have accrued and have not been paid or which hereafter may accrue. The term "blind person" as used herein includes any person who has a vision with or without adjusted glasses suitable to the eye or to the individual not greater than what is known as 2/100 vision. The term "deaf person" as used herein means any person who is wholly deprived of his sense of hearing. The judge of probate shall issue a certificate of exemption to any person exempt from the payment of poll tax by reason of this amendment. This amendment shall be self-executing and retroactive; but the legislature may enact laws designed to carry out the purposes of this amendment.