Section 506. Reexamination of licensees

1.  If  the  commissioner  has
  reasonable grounds to believe that a person  holding  a  license  issued
  pursuant  to this article is not qualified to drive a motor vehicle, the
  commissioner may require such person to  submit  to  an  examination  to
  determine his qualifications.
    2.  The commissioner may require every person holding a license issued
  pursuant to this article to submit to such an examination  as  shall  be
  determined  by him to be appropriate if such person has been involved in
  three accidents while driving a motor vehicle  or  motorcycle  within  a
  period  of  eighteen  months,  if  such  accidents  were  required to be
  reported by section six hundred five of this chapter.
    3. If the licensee satisfactorily  passes  any  such  examination,  he
  shall  be  so informed and his license shall continue to be valid. If he
  fails to pass, the commissioner shall take such reasonable action as may
  be required.  Such action may consist of imposing  restrictions  on  the
  use  of  the  license  of  such person, in suspending such license for a
  definite or indefinite period, or in revoking such license. If any  such
  person  fails  after  reasonable  notice  or  refuses  to  submit  to an
  examination, the commissioner may revoke his license or suspend  it  for
  an indefinite period solely because of such failure or refusal.
    4.  Any  person  holding a license issued pursuant to this chapter who
  suffers permanent loss of use of one or both hands or arms or of one  or
  both  feet or legs, or one eye shall, before operating any motor vehicle
  or motorcycle make report thereof to the commissioner,  who  shall  take
  such  reasonable  action  as  may be proper under the provisions of this
  section.
    5. Upon the permanent loss of use of both eyes a license issued  under
  this article shall be null and void.